Journal Home > Volume 12 , Issue 8

Reliable and economical energy storage technologies are urgently required to ensure sustainable energy supply. Hydrogen (H2) is an energy carrier that can be produced environment-friendly by renewable power to split water (H2O) via electrochemical cells. By this way, electric energy is stored as chemical energy of H2, and the storage can be large-scale and economical. Among the electrochemical technologies for H2O electrolysis, solid oxide electrolysis cells (SOECs) operated at temperatures above 500 ℃ have the benefits of high energy conversion efficiency and economic feasibility. In addition to the H2O electrolysis, SOECs can also be employed for CO2 electrolysis and H2O–CO2 co-electrolysis to produce value-added chemicals of great economic and environmental significance. However, the SOEC technology is not yet fully ready for commercial deployment because of material limitations of the key components, such as electrolytes, air electrodes, and fuel electrodes. As is well known, the reactions in SOEC are, in principle, inverse to the reactions in solid oxide fuel cells (SOFCs). Component materials of SOECs are currently adopted from SOFC materials. However, their performance stability issues are evident, and need to be overcome by materials development in line with the unique requirements of the SOEC materials. Key topics discussed in this review include SOEC critical materials and their optimization, material degradation and its safeguards, future research directions, and commercialization challenges, from both traditional oxygen ion (O2−)-conducting SOEC (O-SOEC) and proton (H+)-conducting SOEC (H-SOEC) perspectives. It is worth to believe that H2O or/and CO2 electrolysis by SOECs provides a viable solution for future energy storage and conversion.


menu
Abstract
Full text
Outline
About this article

Materials of solid oxide electrolysis cells for H2O and CO2 electrolysis: A review

Show Author's information Peng Qiua,bCheng LiaBo LiuaDong YanaJian LiaLichao Jiaa( )
Center for Fuel Cell Innovation, School of Materials Science and Engineering, State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
School of Materials Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China

Abstract

Reliable and economical energy storage technologies are urgently required to ensure sustainable energy supply. Hydrogen (H2) is an energy carrier that can be produced environment-friendly by renewable power to split water (H2O) via electrochemical cells. By this way, electric energy is stored as chemical energy of H2, and the storage can be large-scale and economical. Among the electrochemical technologies for H2O electrolysis, solid oxide electrolysis cells (SOECs) operated at temperatures above 500 ℃ have the benefits of high energy conversion efficiency and economic feasibility. In addition to the H2O electrolysis, SOECs can also be employed for CO2 electrolysis and H2O–CO2 co-electrolysis to produce value-added chemicals of great economic and environmental significance. However, the SOEC technology is not yet fully ready for commercial deployment because of material limitations of the key components, such as electrolytes, air electrodes, and fuel electrodes. As is well known, the reactions in SOEC are, in principle, inverse to the reactions in solid oxide fuel cells (SOFCs). Component materials of SOECs are currently adopted from SOFC materials. However, their performance stability issues are evident, and need to be overcome by materials development in line with the unique requirements of the SOEC materials. Key topics discussed in this review include SOEC critical materials and their optimization, material degradation and its safeguards, future research directions, and commercialization challenges, from both traditional oxygen ion (O2−)-conducting SOEC (O-SOEC) and proton (H+)-conducting SOEC (H-SOEC) perspectives. It is worth to believe that H2O or/and CO2 electrolysis by SOECs provides a viable solution for future energy storage and conversion.

Keywords: electrode, electrolytes, CO2 electrolysis, solid oxide electrolysis cells (SOECs), water (H2O) electrolysis

References(415)

[1]
Balakrishnan P, Shabbir MS, Siddiqi AF, et al. Current status and future prospects of renewable energy: A case study. Energ Source Part A 2020, 42: 2698–2703.
[2]
Franco A, Salza P. Strategies for optimal penetration of intermittent renewables in complex energy systems based on techno-operational objectives. Renew Energ 2011, 36: 743–753.
[3]
Moriarty P, Honnery D. Can renewable energy power the future? Energ Policy 2016, 93: 3–7.
[4]
Larcher D, Tarascon JM. Towards greener and more sustainable batteries for electrical energy storage. Nat Chem 2015, 7: 19–29.
[5]
Scrosati B, Garche J. Lithium batteries: Status, prospects and future. J Power Sources 2010, 195: 2419–2430.
[6]
Gür TM. Review of electrical energy storage technologies, materials and systems: Challenges and prospects for large-scale grid storage. Energ Environ Sci 2018, 11: 2696–2767.
[7]
Lv WG, Wang ZH, Cao HB, et al. A critical review and analysis on the recycling of spent lithium-ion batteries. ACS Sustainable Chem Eng 2018, 6: 1504–1521.
[8]
Edwards PP, Kuznetsov VL, David WIF, et al. Hydrogen and fuel cells: Towards a sustainable energy future. Energ Policy 2008, 36: 4356–4362.
[9]
Bhandari R, Shah RR. Hydrogen as energy carrier: Techno-economic assessment of decentralized hydrogen production in Germany. Renew Energ 2021, 177: 915–931.
[10]
Mayyas A, Wei M, Levis G. Hydrogen as a long-term, large-scale energy storage solution when coupled with renewable energy sources or grids with dynamic electricity pricing schemes. Int J Hydrogen Energ 2020, 45: 16311–16325.
[11]
Venkataraman V, Pérez-Fortes M, Wang LG, et al. Reversible solid oxide systems for energy and chemical applications—Review & perspectives. J Energy Storage 2019, 24: 100782.
[12]
Mogensen MB. Materials for reversible solid oxide cells. Curr Opin Electrochem 2020, 21: 265–273.
[13]
Mogensen MB, Chen M, Frandsen HL, et al. Reversible solid-oxide cells for clean and sustainable energy. Clean Energy 2019, 3: 175–201.
[14]
Lei LB, Zhang JH, Yuan ZH, et al. Progress report on proton conducting solid oxide electrolysis cells. Adv Funct Mater 2019, 29: 1903805.
[15]
Götz M, Lefebvre J, Mörs F, et al. Renewable Power-to-gas: A technological and economic review. Renew Energ 2016, 85: 1371–1390.
[16]
Duan XC, Xu JT, Wei ZX, et al. Metal-free carbon materials for CO2 electrochemical reduction. Adv Mater 2017, 29: 1701784.
[17]
Soeder DJ. Fossil fuels and climate change. In: Fracking and the Environment. Soeder DJ, Ed. Cham, Switzerland: Springer Cham, 2020: 155–185.
DOI
[18]
Norhasyima RS, Mahlia TMI. Advances in CO2 utilization technology: A patent landscape review. J CO2 Util 2018, 26: 323–335.
[19]
Cannone SF, Lanzini A, Santarelli M. A review on CO2 capture technologies with focus on CO2-enhanced methane recovery from hydrates. Energies 2021, 14: 387.
[20]
Atanda L, Wahab MA, Beltramini J. Recent progress on catalyst development for CO2 conversion into value-added chemicals by photo- and electroreduction. In: Engineering Solutions for CO2 Conversion. Reina TR, Arellano-Garcia H, Odriozola JA, Eds. Weinheim, Germany: Wiley-VEH, 2021: 335–360.
DOI
[21]
Sun MY, Zhao BH, Chen FP, et al. Thermally-assisted photocatalytic CO2 reduction to fuels. Chem Eng J 2021, 408: 127280.
[22]
Alam MI, Cheula R, Moroni G, et al. Mechanistic and multiscale aspects of thermo-catalytic CO2 conversion to C1 products. Catal Sci Technol 2021, 11: 6601–6629.
[23]
Saravanan A, Senthil Kumar P, Vo DVN, et al. A comprehensive review on different approaches for CO2 utilization and conversion pathways. Chem Eng Sci 2021, 236: 116515.
[24]
Song YF, Zhang XM, Xie K, et al. High-temperature CO2 electrolysis in solid oxide electrolysis cells: Developments, challenges, and prospects. Adv Mater 2019, 31: 1902033.
[25]
Yin Z, Gao DF, Yao SY, et al. Highly selective palladium-copper bimetallic electrocatalysts for the electrochemical reduction of CO2 to CO. Nano Energy 2016, 27: 35–43.
[26]
Dinh CT, Burdyny T, Kibria MG, et al. CO2 electroreduction to ethylene via hydroxide-mediated copper catalysis at an abrupt interface. Science 2018, 360: 783–787.
[27]
Weng W, Tang LZ, Xiao W. Capture and electro-splitting of CO2 in molten salts. J Energy Chem 2019, 28: 128–143.
[28]
Song YF, Zhou ZW, Zhang XM, et al. Pure CO2 electrolysis over an Ni/YSZ cathode in a solid oxide electrolysis cell. J Mater Chem A 2018, 6: 13661–13667.
[29]
Ebbesen SD, Jensen SH, Hauch A, et al. High temperature electrolysis in alkaline cells, solid proton conducting cells, and solid oxide cells. Chem Rev 2014, 114: 10697–10734.
[30]
Wang Y, Liu T, Lei LB, et al. High temperature solid oxide H2O/CO2 co-electrolysis for syngas production. Fuel Process Technol 2017, 161: 248–258.
[31]
Fu QX, Mabilat C, Zahid M, et al. Syngas production via high-temperature steam/CO2 co-electrolysis: An economic assessment. Energ Environ Sci 2010, 3: 1382–1397.
[32]
Graves C, Ebbesen SD, Mogensen M. Co-electrolysis of CO2 and H2O in solid oxide cells: Performance and durability. Solid State Ionics 2011, 192: 398–403.
[33]
Hauch A, Küngas R, Blennow P, et al. Recent advances in solid oxide cell technology for electrolysis. Science 2020, 370: eaba6118.
[34]
Laguna-Bercero MA. Recent advances in high temperature electrolysis using solid oxide fuel cells: A review. J Power Sources 2012, 203: 4–16.
[35]
Hussain S, Li YP. Review of solid oxide fuel cell materials: Cathode, anode, and electrolyte. Energy Trans 2020, 4: 113–126.
[36]
Ni M, Leung MKH, Leung DYC. Technological development of hydrogen production by solid oxide electrolyzer cell (SOEC). Int J Hydrogen Energ 2008, 33: 2337–2354.
[37]
Zhang LX, Hu SQ, Zhu XF, et al. Electrochemical reduction of CO2 in solid oxide electrolysis cells. J Energy Chem 2017, 26: 593–601.
[38]
Kwon OH, Choi GM. Electrical conductivity of thick film YSZ. Solid State Ionics 2006, 177: 3057–3062.
[39]
Coduri M, Checchia S, Longhi M, et al. Rare earth doped ceria: The complex connection between structure and properties. Front Chem 2018, 6: 526.
[40]
Shi HG, Su C, Ran R, et al. Electrolyte materials for intermediate-temperature solid oxide fuel cells. Prog Nat Sci 2020, 30: 764–774.
[41]
Yin SL, Zeng YW, Li CM, et al. Investigation of Sm0.2Ce0.8O1.9/Na2CO3 nanocomposite electrolytes: Preparation, interfacial microstructures, and ionic conductivities. ACS Appl Mater Interfaces 2013, 5: 12876–12886.
[42]
Kuo YL, Su YM, Chou HL. A facile synthesis of high quality nanostructured CeO2 and Gd2O3-doped CeO2 solid electrolytes for improved electrochemical performance. Phys Chem Chem Phys 2015, 17: 14193–14200.
[43]
Chen YH, Cheng ZX, Yang Y, et al. Novel quasi-symmetric solid oxide fuel cells with enhanced electrochemical performance. J Power Sources 2016, 310: 109–117.
[44]
He YJ, Fan LD, Afzal M, et al. Cobalt oxides coated commercial Ba0.5Sr0.5Co0.8Fe0.2O3−δ as high performance cathode for low-temperature SOFCs. Electrochim Acta 2016, 191: 223–229.
[45]
Singh B, Ghosh S, Aich S, et al. Low temperature solid oxide electrolytes (LT-SOE): A review. J Power Sources 2017, 339: 103–135.
[46]
Sun WP, Shi Z, Qian J, et al. In-situ formed Ce0.8Sm0.2O2−δ@Ba(Ce,Zr)1−x(Sm,Y)xO3−δ core/shell electron-blocking layer towards Ce0.8Sm0.2O2−δ-based solid oxide fuel cells with high open circuit voltages. Nano Energy 2014, 8: 305–311.
[47]
Eguchi K, Hatagishi T, Arai H. Power generation and steam electrolysis characteristics of an electrochemical cell with a zirconia- or ceria-based electrolyte. Solid State Ionics 1996, 86–88: 1245–1249.
[48]
Sumi H, Suda E, Mori M. Blocking layer for prevention of current leakage for reversible solid oxide fuel cells and electrolysis cells with ceria-based electrolyte. Int J Hydrogen Energ 2017, 42: 4449–4455.
[49]
Kostogloudis GC, Tsiniarakis G, Ftikos C. Chemical reactivity of perovskite oxide SOFC cathodes and yttria stabilized zirconia. Solid State Ionics 2000, 135: 529–535.
[50]
Adijanto L, Küngas R, Bidrawn F, et al. Stability and performance of infiltrated La0.8Sr0.2CoxFe1−xO3 electrodes with and without Sm0.2Ce0.8O1.9 interlayers. J Power Sources 2011, 196: 5797–5802.
[51]
Ishihara T, Matsuda H, Takita Y. Doped LaGaO3 perovskite type oxide as a new oxide ionic conductor. J Am Chem Soc 1994, 116: 3801–3803.
[52]
Lv HF, Lin L, Zhang XM, et al. In situ exsolved FeNi3 nanoparticles on nickel doped Sr2Fe1.5Mo0.5O6−δ perovskite for efficient electrochemical CO2 reduction reaction. J Mater Chem A 2019, 7: 11967–11975.
[53]
Ishihara T, Jirathiwathanakul N, Zhong H. Intermediate temperature solid oxide electrolysis cell using LaGaO3 based perovskite electrolyte. Energ Environ Sci 2010, 3: 665–672.
[54]
Park S, Kim Y, Han H, et al. In situ exsolved Co nanoparticles on Ruddlesden–Popper material as highly active catalyst for CO2 electrolysis to CO. Appl Catal B-Environ 2019, 248: 147–156.
[55]
Kharton VV, Marques FMB, Atkinson A. Transport properties of solid oxide electrolyte ceramics: A brief review. Solid State Ionics 2004, 174: 135–149.
[56]
Wei T, Ji Y, Meng XW, et al. Sr2NiMoO6−δ as anode material for LaGaO3-based solid oxide fuel cell. Electrochem Commun 2008, 10: 1369–1372.
[57]
Gao Z, Miller EC, Barnett SA. A high power density intermediate-temperature solid oxide fuel cell with thin (La0.9Sr0.1)0.98(Ga0.8Mg0.2)O3−δ electrolyte and nano-scale anode. Adv Funct Mater 2014, 24: 5703–5709.
[58]
Bi ZH, Yi BL, Wang ZW, et al. A high-performance anode-supported SOFC with LDC–LSGM bilayer electrolytes. Electrochem Solid-State Lett 2004, 7: A105–A107.
[59]
Wan JH, Yan JQ, Goodenough JB. LSGM-based solid oxide fuel cell with 1.4 W/cm2 power density and 30 day long-term stability. J Electrochem Soc 2005, 152: A1511–A1515.
[60]
Yang ZB, Jin C, Yang CH, et al. Ba0.9Co0.5Fe0.4Nb0.1O3−δ as novel oxygen electrode for solid oxide electrolysis cells. Int J Hydrogen Energ 2011, 36: 11572–11577.
[61]
Du YH, Sammes NM, Tompsett GA, et al. Extruded tubular strontium- and magnesium-doped lanthanum gallate, gadolinium-doped ceria, and yttria-stabilized zirconia electrolytes. J Electrochem Soc 2003, 150: A74–A78.
[62]
Azad AM, Larose S, Akbar SA. Bismuth oxide-based solid electrolytes for fuel cells. J Mater Sci 1994, 29: 4135–4151.
[63]
Takahashi T, Iwahara H, Nagai Y. High oxide ion conduction in sintered Bi2O3 containing SrO, CaO or La2O3. J Appl Electrochem 1972, 2: 97–104.
[64]
Conflant P, Boivin JC, Thomas D. Le diagramme des phases solides du systeme Bi2O3–CaO. J Solid State Chem 1976, 18: 133–140. (in French)
[65]
Levin EM, Roth RS. Polymorphism of bismuth sesquioxide. I. Pure Bi2O3. J Res Natl Bur Stand A Phys Chem 1964, 68A: 189–195.
[66]
Verkerk MJ, Keizer K, Burggraaf AJ. High oxygen ion conduction in sintered oxides of the Bi2O3–Er2O3 system. J Appl Electrochem 1980, 10: 81–90.
[67]
Jung DW, Lee KT, Wachsman ED. Terbium and tungsten co-doped bismuth oxide electrolytes for low temperature solid oxide fuel cells. J Korean Ceram Soc 2014, 51: 260–264.
[68]
Aguadero A, Fawcett L, Taub S, et al. Materials development for intermediate-temperature solid oxide electrochemical devices. J Mater Sci 2012, 47: 3925–3948.
[69]
Yaremchenko AA, Kharton VV, Naumovich EN, et al. Stability of δ-Bi2O3-based solid electrolytes. Mater Res Bull 2000, 35: 515–520.
[70]
Ayhan YS, Buyukaksoy A. Impact of fabrication temperature on the stability of yttria doped bismuth oxide ceramics. Solid State Ionics 2019, 338: 66–73.
[71]
Seo DJ, Ryu KO, Park SB, et al. Synthesis and properties of Ce1−xGdxO2−x/2 solid solution prepared by flame spray pyrolysis. Mater Res Bull 2006, 41: 359–366.
[72]
Xin XS, Lü Z, Ding ZH, et al. Synthesis and characteristics of nanocrystalline YSZ by homogeneous precipitation and its electrical properties. J Alloys Compd 2006, 425: 69–75.
[73]
Peck DH, Song RH, Kim JH, et al. Electrical conductivity of scandia stabilized zirconia for membranes in solid oxide fuel cells. Proc Vol 2005, 2005–2007: 947–953.
[74]
Jasinski P. Electrical properties of nanocrystalline Sm-doped ceria ceramics. Solid State Ionics 2006, 177: 2509–2512.
[75]
Rambabu B, Ghosh S, Zhao WC, et al. Innovative processing of dense LSGM electrolytes for IT-SOFC’s. J Power Sources 2006, 159: 21–28.
[76]
Khan MS, Xu XY, Li MR, et al. Evaluation of SrCo0.8Nb0.2O3−δ, SrCo0.8Ta0.2O3−δ and SrCo0.8Nb0.1Ta0.1O3−δ as air electrode materials for solid oxide electrolysis and reversible solid oxide cells. Electrochim Acta 2019, 321: 134654.
[77]
Zheng Y, Wang JC, Yu B, et al. A review of high temperature co-electrolysis of H2O and CO2 to produce sustainable fuels using solid oxide electrolysis cells (SOECs): Advanced materials and technology. Chem Soc Rev 2017, 46: 1427–1463.
[78]
Zheng Y, Chen ZW, Zhang JJ. Solid oxide electrolysis of H2O and CO2 to produce hydrogen and low-carbon fuels. Electrochem Energy R 2021, 4: 508–517.
[79]
Tao ZT, Bi L, Yan LT, et al. A novel single phase cathode material for a proton-conducting SOFC. Electrochem Commun 2009, 11: 688–690.
[80]
Heidari D, Javadpour S, Chan SH. Optimization of BSCF–SDC composite air electrode for intermediate temperature solid oxide electrolyzer cell. Energ Convers Manage 2017, 136: 78–84.
[81]
Laurencin J, Hubert M, Sanchez DF, et al. Degradation mechanism of La0.6Sr0.4Co0.2Fe0.8O3−δ/Gd0.1Ce0.9O2−δ composite electrode operated under solid oxide electrolysis and fuel cell conditions. Electrochim Acta 2017, 241: 459–476.
[82]
Hjalmarsson P, Sun XF, Liu YL, et al. Influence of the oxygen electrode and inter-diffusion barrier on the degradation of solid oxide electrolysis cells. J Power Sources 2013, 223: 349–357.
[83]
Heidari D, Javadpour S, Chan SH. An evaluation of electrochemical performance of a solid oxide electrolyzer cell as a function of co-sintered YSZ–SDC bilayer electrolyte thickness. Energ Convers Manage 2017, 150: 567–573.
[84]
Zhang WQ, Yu B, Xu JM. Investigation of single SOEC with BSCF anode and SDC barrier layer. Int J Hydrogen Energ 2012, 37: 837–842.
[85]
Zhang SL, Wang HQ, Lu MY, et al. Cobalt-substituted SrTi0.3Fe0.7O3−δ: A stable high-performance oxygen electrode material for intermediate-temperature solid oxide electrochemical cells. Energ Environ Sci 2018, 11: 1870–1879.
[86]
Song YF, Chen YB, Xu MG, et al. A cobalt-free multi-phase nanocomposite as near-ideal cathode of intermediate-temperature solid oxide fuel cells developed by smart self-assembly. Adv Mater 2020, 32: 1906979.
[87]
Chen YB, Zhou W, Ding D, et al. Advances in cathode materials for solid oxide fuel cells: Complex oxides without alkaline earth metal elements. Adv Energy Mater 2015, 5: 1500537.
[88]
Niemczyk A, Zheng K, Cichy K, et al. High Cu content LaNi1−xCuxO3−δ perovskites as candidate air electrode materials for Reversible Solid Oxide Cells. Int J Hydrogen Energ 2020, 45: 29449–29464.
[89]
Ma QL, Balaguer M, Pérez-Coll D, et al. Characterization and optimization of La0.97Ni0.5Co0.5O3–−δ-based air-electrodes for solid oxide cells. ACS Appl Energy Mater 2018, 1: 2784–2792.
[90]
Chrzan A, Ovtar S, Jasinski P, et al. High performance LaNi1−xCoxO3−δ (x = 0.4 to 0.7) infiltrated oxygen electrodes for reversible solid oxide cells. J Power Sources 2017, 353: 67–76.
[91]
Liu Q, Dong XH, Xiao GL, et al. A novel electrode material for symmetrical SOFCs. Adv Mater 2010, 22: 5478–5482.
[92]
Liu Q, Yang CH, Dong XH, et al. Perovskite Sr2Fe1.5Mo0.5O6−δ as electrode materials for symmetrical solid oxide electrolysis cells. Int J Hydrogen Energ 2010, 35: 10039–10044.
[93]
Park S, Choi S, Shin J, et al. A collaborative study of sintering and composite effects for a PrBa0.5Sr0.5Co1.5Fe0.5O5+δ IT-SOFC cathode. RSC Adv 2014, 4: 1775–1781.
[94]
Li J, Zhang Q, Qiu P, et al. A CO2-tolerant La2NiO4+δ-coated PrBa0.5Sr0.5Co1.5Fe0.5O5+δ cathode for intermediate temperature solid oxide fuel cells. J Power Sources 2017, 342: 623–628.
[95]
Jun A, Kim J, Shin J, et al. Achieving high efficiency and eliminating degradation in solid oxide electrochemical cells using high oxygen-capacity perovskite. Angew Chem Int Ed 2016, 55: 12512–12515.
[96]
Tian YF, Li J, Liu YY, et al. Preparation and properties of PrBa0.5Sr0.5Co1.5Fe0.5O5+δ as novel oxygen electrode for reversible solid oxide electrochemical cell. Int J Hydrogen Energ 2018, 43: 12603–12609.
[97]
Tian YF, Liu Y, Wang WJ, et al. High performance and stability of double perovskite-type oxide NdBa0.5Ca0.5Co1.5Fe0.5O5+δ as an oxygen electrode for reversible solid oxide electrochemical cell. J Energy Chem 2020, 43: 108–115.
[98]
Tian YF, Wang WJ, Liu Y, et al. Achieving strong coherency for a composite electrode via one-pot method with enhanced electrochemical performance in reversible solid oxide cells. ACS Catal 2021, 11: 3704–3714.
[99]
Li GD, Gou YJ, Cheng XJ, et al. Enhanced electrochemical performance of the Fe-based layered perovskite oxygen electrode for reversible solid oxide cells. ACS Appl Mater Interfaces 2021, 13: 34282–34291.
[100]
Zheng YF, Yang H, Pan ZH, et al. A Ca and Fe co-doped layered perovskite as stable air electrode in solid oxide electrolyzer cells under high-current electrolysis. Electrochim Acta 2017, 251: 581–587.
[101]
Huan Y, Chen SX, Zeng R, et al. Intrinsic effects of Ruddlesden–Popper-based bifunctional catalysts for high-temperature oxygen reduction and evolution. Adv Energy Mater 2019, 9: 1901573.
[102]
Ogier T, Bassat JM, Mauvy F, et al. Enhanced performances of structured oxygen electrodes for high temperature steam electrolysis. Fuel Cells 2013, 13: 536–541.
[103]
Chauveau F, Mougin J, Bassat JM, et al. A new anode material for solid oxide electrolyser: The neodymium nickelate Nd2NiO4+δ. J Power Sources 2010, 195: 744–749.
[104]
Tong X, Zhou F, Yang SB, et al. Performance and stability of Ruddlesden–Popper La2NiO4+δ oxygen electrodes under solid oxide electrolysis cell operation conditions. Ceram Int 2017, 43: 10927–10933.
[105]
Laguna-Bercero MA, Monzón H, Larrea A, et al. Improved stability of reversible solid oxide cells with a nickelate-based oxygen electrode. J Mater Chem A 2016, 4: 1446–1453.
[106]
Liang FY, He GH, Jia LJ, et al. Cobalt-free dual-phase oxygen transporting membrane reactor for the oxidative dehydrogenation of ethane. Sep Purif Technol 2019, 211: 966–971.
[107]
Jiang HG, Lu ZM, Qian B, et al. Bi-doped La1.5Sr0.5Ni0.5Mn0.5O4+δ as an efficient air electrode material for SOEC. Int J Hydrogen Energ 2021, 46: 36037–36045.
[108]
Vibhu V, Vinke IC, Eichel RA, et al. Cobalt substituted Pr2Ni1−xCoxO4+δ (x = 0, 0.1, 0.2) oxygen electrodes: Impact on electrochemical performance and durability of solid oxide electrolysis cells. J Power Sources 2021, 482: 228909.
[109]
Vibhu V, Vinke IC, Eichel RA, et al. La2Ni1−xCoxO4+δ (x = 0.0, 0.1 and 0.2) based efficient oxygen electrode materials for solid oxide electrolysis cells. J Power Sources 2019, 444: 227292.
[110]
Zheng YF, Jiang HG, Wang S, et al. Mn-doped Ruddlesden–Popper oxide La1.5Sr0.5NiO4+δ as a novel air electrode material for solid oxide electrolysis cells. Ceram Int 2021, 47: 1208–1217.
[111]
Liu SM, Yu B, Zhang WQ, et al. Electrochemical performance of Co-containing mixed oxides as oxygen electrode materials for intermediate-temperature solid oxide electrolysis cells. Int J Hydrogen Energ 2016, 41: 15952–15959.
[112]
Li PZ, Yang W, Tian CJ, et al. Electrochemical performance of La2NiO4+δ–Ce0.55La0.45O2−δ as a promising bifunctional oxygen electrode for reversible solid oxide cells. J Adv Ceram 2021, 10: 328–337.
[113]
Li M, Hua B, Chen J, et al. Charge transfer dynamics in RuO2/perovskite nanohybrid for enhanced electrocatalysis in solid oxide electrolyzers. Nano Energy 2019, 57: 186–194.
[114]
Chen KF, Ai N, Jiang SP. Performance and structural stability of Gd0.2Ce0.8O1.9 infiltrated La0.8Sr0.2MnO3 nano-structured oxygen electrodes of solid oxide electrolysis cells. Int J Hydrogen Energ 2014, 39: 10349–10358.
[115]
Shahrokhi S, Babaei A, Zamani C. Reversible operation of La0.8Sr0.2MnO3 oxygen electrode infiltrated with Ruddlesden–Popper and perovskite lanthanum nickel cobaltite. Int J Hydrogen Energ 2018, 43: 23091–23100.
[116]
Chen KF, Ai N, Jiang SP. Enhanced electrochemical performance and stability of (La,Sr)MnO3–(Gd,Ce)O2 oxygen electrodes of solid oxide electrolysis cells by palladium infiltration. Int J Hydrogen Energ 2012, 37: 1301–1310.
[117]
Ai N, Li N, He S, et al. Highly active and stable Er0.4Bi1.6O3 decorated La0.76Sr0.19MnO3+δ nanostructured oxygen electrodes for reversible solid oxide cells. J Mater Chem A 2017, 5: 12149–12157.
[118]
Yang TR, Kollasch SL, Grimes J, et al. (La0.8Sr0.2)0.98MnO3−δ–Zr0.92Y0.16O2−δ:PrOx for oxygen electrode supported solid oxide cells. Appl Catal B-Environ 2022, 306: 121114.
[119]
Almar L, Andreu T, Morata A, et al. High-surface-area ordered mesoporous oxides for continuous operation in high temperature energy applications. J Mater Chem A 2014, 2: 3134–3141.
[120]
Wang YQ, Yang ZB, Han MF, et al. Optimization of Sm0.5Sr0.5CoO3−δ-infiltrated YSZ electrodes for solid oxide fuel cell/electrolysis cell. RSC Adv 2016, 6: 112253–112259.
[121]
Almar L, Morata A, Torrell M, et al. A durable electrode for solid oxide cells: Mesoporous Ce0.8Sm0.2O1.9 scaffolds infiltrated with a Sm0.5Sr0.5CoO3−δ catalyst. Electrochim Acta 2017, 235: 646–653.
[122]
Hernández E, Baiutti F, Morata A, et al. Infiltrated mesoporous oxygen electrodes for high temperature co-electrolysis of H2O and CO2 in solid oxide electrolysis cells. J Mater Chem A 2018, 6: 9699–9707.
[123]
Torrell M, Almar L, Morata A, et al. Synthesis of mesoporous nanocomposites for their application in solid oxide electrolysers cells: Microstructural and electrochemical characterization. Faraday Discuss 2015, 182: 423–435.
[124]
Song YF, Zhou S, Dong Q, et al. Oxygen evolution reaction over the Au/YSZ interface at high temperature. Angew Chem Int Ed 2019, 58: 4617–4621.
[125]
Wu T, Zhang WQ, Li YF, et al. Micro-/nanohoneycomb solid oxide electrolysis cell anodes with ultralarge current tolerance. Adv Energy Mater 2018, 8: 1802203.
[126]
Shimada H, Yamaguchi T, Kishimoto H, et al. Nanocomposite electrodes for high current density over 3 A·cm−2 in solid oxide electrolysis cells. Nat Commun 2019, 10: 5432.
[127]
Ebbesen SD, Mogensen M. Electrolysis of carbon dioxide in Solid Oxide Electrolysis Cells. J Power Sources 2009, 193: 349–358.
[128]
Sun X, Bonaccorso AD, Graves C, et al. Performance characterization of solid oxide cells under high pressure. Fuel Cells 2015, 15: 697–702.
[129]
Sun XF, Chen M, Liu YL, et al. Durability of solid oxide electrolysis cells for syngas production. J Electrochem Soc 2013, 160: F1074–F1080.
[130]
Chen XB, Guan CZ, Xiao GP, et al. Syngas production by high temperature steam/CO2 coelectrolysis using solid oxide electrolysis cells. Faraday Discuss 2015, 182: 341–351.
[131]
Zhao Z, Qi HY, Tang S, et al. A highly active and stable hybrid oxygen electrode for reversible solid oxide cells. Int J Hydrogen Energ 2021, 46: 36012–36022.
[132]
Li YY, Yang LL, Li WL, et al. A promising strontium and cobalt-free air electrode Pr1−xCaxFeO3−δ for solid oxide electrolysis cell. Int J Hydrogen Energ 2021, 46: 30230–30238.
[133]
Zhou N, Yin YM, Li JC, et al. A robust high performance cobalt-free oxygen electrode La0.5Sr0.5Fe0.8Cu0.15Nb0.05O3−δ for reversible solid oxide electrochemical cell. J Power Sources 2017, 340: 373–379.
[134]
Prasopchokkul P, Seeharaj P, Kim-Lohsoontorn P. Ba0.5Sr0.5(Co0.8Fe0.2)1−xTaxO3−δ perovskite anode in solid oxide electrolysis cell for hydrogen production from high-temperature steam electrolysis. Int J Hydrogen Energ 2021, 46: 7023–7036.
[135]
Meng XX, Shen YC, Xie MH, et al. Novel solid oxide cells with SrCo0.8Fe0.1Ga0.1O3−δ oxygen electrode for flexible power generation and hydrogen production. J Power Sources 2016, 306: 226–232.
[136]
Pan ZH, Liu QL, Zhang L, et al. Experimental and thermodynamic study on the performance of water electrolysis by solid oxide electrolyzer cells with Nb-doped Co-based perovskite anode. Appl Energy 2017, 191: 559–567.
[137]
Choi MB, Singh B, Wachsman ED, et al. Performance of La0.1Sr0.9Co0.8Fe0.2O3−δ and La0.1Sr0.9Co0.8Fe0.2O3−δ–Ce0.9Gd0.1O2 oxygen electrodes with Ce0.9Gd0.1O2 barrier layer in reversible solid oxide fuel cells. J Power Sources 2013, 239: 361–373.
[138]
Kim YD, Yang JY, Saqib M, et al. Cobalt-free perovskite Ba1−xNdxFeO3−δ air electrode materials for reversible solid oxide cells. Ceram Int 2021, 47: 7985–7993.
[139]
Tian YF, Wang WJ, Liu Y, et al. Cobalt-free perovskite oxide La0.6Sr0.4Fe0.8Ni0.2O3−δ as active and robust oxygen electrode for reversible solid oxide cells. ACS Appl Energy Mater 2019, 2: 3297–3305.
[140]
Yan JB, Zhao Z, Shang L, et al. Co-synthesized Y-stabilized Bi2O3 and Sr-substituted LaMnO3 composite anode for high performance solid oxide electrolysis cell. J Power Sources 2016, 319: 124–130.
[141]
Chen ML, Cheng Y, He S, et al. Active, durable bismuth oxide–manganite composite oxygen electrodes: Interface formation induced by cathodic polarization. J Power Sources 2018, 397: 16–24.
[142]
Yang LL, Li YY, Hou ZY, et al. La1−xCaxFeO3−δ air electrode fabricated by glycine–nitrate combustion method for solid oxide electrolysis cell. Ceram Int 2021, 47: 32318–32323.
[143]
Song YF, Zhang XM, Zhou YJ, et al. Promoting oxygen evolution reaction by RuO2 nanoparticles in solid oxide CO2 electrolyzer. Energy Storage Mater 2018, 13: 207–214.
[144]
Chen T, Liu MQ, Yuan C, et al. High performance of intermediate temperature solid oxide electrolysis cells using Nd2NiO4+δ impregnated scandia stabilized zirconia oxygen electrode. J Power Sources 2015, 276: 1–6.
[145]
Yang CH, Jin C, Coffin A, et al. Characterization of infiltrated (La0.75Sr0.25)0.95MnO3 as oxygen electrode for solid oxide electrolysis cells. Int J Hydrogen Energ 2010, 35: 5187–5193.
[146]
Li J, Zhong C, Meng X, et al. Sr2Fe1.5Mo0.5O6−δ–Zr0.84Y0.16O2−δ materials as oxygen electrodes for solid oxide electrolysis cells. Fuel Cells 2014, 14: 1046–1049.
[147]
Song YF, Zhang XM, Zhou YJ, et al. Improving the performance of solid oxide electrolysis cell with gold nanoparticles-modified LSM–YSZ anode. J Energy Chem 2019, 35: 181–187.
[148]
Tan Y, Duan NQ, Wang A, et al. Performance enhancement of solution impregnated nanostructured La0.8Sr0.2Co0.8Ni0.2O3−δ oxygen electrode for intermediate temperature solid oxide electrolysis cells. J Power Sources 2016, 305: 168–174.
[149]
Zheng HY, Tian YF, Zhang LL, et al. La0.8Sr0.2Co0.8Ni0.2O3−δ impregnated oxygen electrode for H2O/CO2 co-electrolysis in solid oxide electrolysis cells. J Power Sources 2018, 383: 93–101.
[150]
Ge L, Sun KQ, Gu YH, et al. Boosting the performance of conventional air electrodes for solid oxide cells by in-situ loading of nano praseodymium oxide. Energ Convers Manage 2021, 249: 114873.
[151]
Ai N, Chen ML, He S, et al. High performance nanostructured bismuth oxide-cobaltite as a durable oxygen electrode for reversible solid oxide cells. J Mater Chem A 2018, 6: 6510–6520.
[152]
Zheng MH, Wang S, Yang Y, et al. Barium carbonate as a synergistic catalyst for the H2O/CO2 reduction reaction at Ni–yttria stabilized zirconia cathodes for solid oxide electrolysis cells. J Mater Chem A 2018, 6: 2721–2729.
[153]
Lay-Grindler E, Laurencin J, Villanova J, et al. Degradation study by 3D reconstruction of a nickel–yttria stabilized zirconia cathode after high temperature steam electrolysis operation. J Power Sources 2014, 269: 927–936.
[154]
Usseglio-Viretta F, Laurencin J, Delette G, et al. Quantitative microstructure characterization of a Ni–YSZ bi-layer coupled with simulated electrode polarisation. J Power Sources 2014, 256: 394–403.
[155]
Jin C, Yang CH, Chen FL. Effects on microstructure of NiO–YSZ anode support fabricated by phase-inversion method. J Membrane Sci 2010, 363: 250–255.
[156]
Yang CL, Li W, Zhang SQ, et al. Fabrication and characterization of an anode-supported hollow fiber SOFC. J Power Sources 2009, 187: 90–92.
[157]
Droushiotis N, Doraswami U, Kanawka K, et al. Characterization of NiO–yttria stabilised zirconia (YSZ) hollow fibres for use as SOFC anodes. Solid State Ionics 2009, 180: 1091–1099.
[158]
Wang JJ, Wang TP, Yu LB, et al. Catalytic CeO2 washcoat over microchanneled supporting cathodes of solid oxide electrolysis cells for efficient and stable CO2 reduction. J Power Sources 2019, 412: 344–349.
[159]
Dong DH, Xu SS, Shao X, et al. Hierarchically ordered porous Ni-based cathode-supported solid oxide electrolysis cells for stable CO2 electrolysis without safe gas. J Mater Chem A 2017, 5: 24098–24102.
[160]
Singh V, Muroyama H, Matsui T, et al. Feasibility of alternative electrode materials for high temperature CO2 reduction on solid oxide electrolysis cell. J Power Sources 2015, 293: 642–648.
[161]
Kim-Lohsoontorn P, Bae J. Electrochemical performance of solid oxide electrolysis cell electrodes under high-temperature coelectrolysis of steam and carbon dioxide. J Power Sources 2011, 196: 7161–7168.
[162]
Lang M, Raab S, Lemcke MS, et al. Long term behavior of solid oxide electrolyser (SOEC) stacks. ECS Trans 2019, 91: 2713–2725.
[163]
Holtappels P, de Haart LGJ, Stimming U, et al. Reaction of CO/CO2 gas mixtures on Ni–YSZ cermet electrodes. J Appl Electrochem 1999, 29: 561–568.
[164]
Ioannidou E, Neofytidis C, Sygellou L, et al. Au-doped Ni/GDC as an improved cathode electrocatalyst for H2O electrolysis in SOECs. Appl Catal B-Environ 2018, 236: 253–264.
[165]
Li YH, Li P, Hu BB, et al. A nanostructured ceramic fuel electrode for efficient CO2/H2O electrolysis without safe gas. J Mater Chem A 2016, 4: 9236–9243.
[166]
Yang CH, Li J, Newkirk J, et al. Co-electrolysis of H2O and CO2 in a solid oxide electrolysis cell with hierarchically structured porous electrodes. J Mater Chem A 2015, 3: 15913–15919.
[167]
Zhang XM, Song YF, Guan F, et al. (La0.75Sr0.25)0.95(Cr0.5Mn0.5)O3−δ–Ce0.8Gd0.2O1.9 scaffolded composite cathode for high temperature CO2 electroreduction in solid oxide electrolysis cell. J Power Sources 2018, 400: 104–113.
[168]
Huang ZD, Qi HY, Zhao Z, et al. Efficient CO2 electroreduction on a solid oxide electrolysis cell with La0.6Sr0.4Co0.2Fe0.8O3−δ–Gd0.2Ce0.8O2−δ infiltrated electrode. J Power Sources 2019, 434: 226730.
[169]
Kumari N, Haider MA, Tiwari PK, et al. Carbon dioxide reduction on the composite of copper and praseodymium-doped ceria electrode in a solid oxide electrolysis cells. Ionics 2019, 25: 3165–3177.
[170]
Wang WY, Gan LZ, Lemmon JP, et al. Enhanced carbon dioxide electrolysis at redox manipulated interfaces. Nat Commun 2019, 10: 1550.
[171]
Qi WT, Xie K, Liu M, et al. Single-phase nickel-doped ceria cathode with in situ grown nickel nanocatalyst for direct high-temperature carbon dioxide electrolysis. RSC Adv 2014, 4: 40494–40504.
[172]
Jin C, Yang CH, Zhao F, et al. La0.75Sr0.25Cr0.5Mn0.5O3 as hydrogen electrode for solid oxide electrolysis cells. Int J Hydrogen Energ 2011, 36: 3340–3346.
[173]
Xi XA, Liu JW, Luo WZ, et al. Unraveling the enhanced kinetics of Sr2Fe1+xMo1−xO6−δ electrocatalysts for high-performance solid oxide cells. Adv Energy Mater 2021, 11: 2102845.
[174]
Li YH, Chen XR, Yang Y, et al. Mixed-conductor Sr2Fe1.5Mo0.5O6−δ as robust fuel electrode for pure CO2 reduction in solid oxide electrolysis cell. ACS Sustainable Chem Eng 2017, 5: 11403–11412.
[175]
Qi WT, Gan Y, Yin D, et al. Remarkable chemical adsorption of manganese-doped titanate for direct carbon dioxide electrolysis. J Mater Chem A 2014, 2: 6904–6915.
[176]
Li YX, Zhou JE, Dong DH, et al. Composite fuel electrode La0.2Sr0.8TiO3−δ–Ce0.8Sm0.2O2−δ for electrolysis of CO2 in an oxygen-ion conducting solid oxide electrolyser. Phys Chem Chem Phys 2012, 14: 15547–15553.
[177]
Hou YT, Wang LJ, Bian LZ, et al. Effect of high-valence elements doping at B site of La0.5Sr0.5FeO3−δ. Ceram Int 2022, 48: 4223–4229.
[178]
Peña MA, Fierro JLG. Chemical structures and performance of perovskite oxides. Chem Rev 2001, 101: 1981–2017.
[179]
Xu XM, Zhong YJ, Shao ZP. Double perovskites in catalysis, electrocatalysis, and photo(electro)catalysis. Trends Chem 2019, 1: 410–424.
[180]
Hu SQ, Zhang LX, Liu HY, et al. Alkaline-earth elements (Ca, Sr and Ba) doped LaFeO3−δ cathodes for CO2 electroreduction. J Power Sources 2019, 443: 227268.
[181]
Sun C, Bian LZ, Qi J, et al. Boosting CO2 directly electrolysis by electron doping in Sr2Fe1.5Mo0.5O6−δ double perovskite cathode. J Power Sources 2022, 521: 230984.
[182]
Jiang YN, Yang Y, Xia CR, et al. Sr2Fe1.4Mn0.1Mo0.5O6−δ perovskite cathode for highly efficient CO2 electrolysis. J Mater Chem A 2019, 7: 22939–22949.
[183]
Zhou YJ, Zhou ZW, Song YF, et al. Enhancing CO2 electrolysis performance with vanadium-doped perovskite cathode in solid oxide electrolysis cell. Nano Energy 2018, 50: 43–51.
[184]
Yajima T, Takeiri F, Aidzu K, et al. A labile hydride strategy for the synthesis of heavily nitridized BaTiO3. Nat Chem 2015, 7: 1017–1023.
[185]
Su F, Xia CR, Peng RR. Novel fluoride-doped barium cerate applied as stable electrolyte in proton conducting solid oxide fuel cells. J Eur Ceram Soc 2015, 35: 3553–3558.
[186]
Zhang ZB, Zhu YL, Zhong YJ, et al. Anion doping: A new strategy for developing high-performance perovskite-type cathode materials of solid oxide fuel cells. Adv Energy Mater 2017, 7: 1700242.
[187]
Li GD, Gou YJ, Ren RZ, et al. Fluorination intensifying oxygen evolution reaction for high-temperature steam electrolysis. Energy Material Advances 2023, 4: 0029.
[188]
Wang Y, Wang H, Liu T, et al. Improving the chemical stability of BaCe0.8Sm0.2O3−δ electrolyte by Cl doping for proton-conducting solid oxide fuel cell. Electrochem Commun 2013, 28: 87–90.
[189]
Li YH, Li Y, Wan YH, et al. Perovskite oxyfluoride electrode enabling direct electrolyzing carbon dioxide with excellent electrochemical performances. Adv Energy Mater 2019, 9: 1803156.
[190]
Park S, Han H, Yoon W, et al. Improving a sulfur-tolerant Ruddlesden–Popper catalyst by fluorine doping for CO2 electrolysis reaction. ACS Sustainable Chem Eng 2020, 8: 6564–6571.
[191]
Wei T, Qiu P, Jia LC, et al. Power and carbon monoxide co-production by a proton-conducting solid oxide fuel cell with La0.6Sr0.2Cr0.85Ni0.15O3−δ for on-cell dry reforming of CH4 by CO2. J Mater Chem A 2020, 8: 9806–9812.
[192]
Neagu D, Oh TS, Miller DN, et al. Nano-socketed nickel particles with enhanced coking resistance grown in situ by redox exsolution. Nat Commun 2015, 6: 8120.
[193]
Wei T, Jia LC, Zheng HY, et al. LaMnO3-based perovskite with in situ exsolved Ni nanoparticles: A highly active, performance stable and coking resistant catalyst for CO2 dry reforming of CH4. Appl Catal A-Gen 2018, 564: 199–207.
[194]
Wei T, Jia LC, Luo JL, et al. CO2 dry reforming of CH4 with Sr and Ni co-doped LaCrO3 perovskite catalysts. Appl Surf Sci 2020, 506: 144699.
[195]
Li C, Deng YT, Yang LP, et al. An active and stable hydrogen electrode of solid oxide cells with exsolved Fe–Co–Ni nanoparticles from Sr2FeCo0.2Ni0.2Mo0.6O6−δ double-perovskite. Adv Powder Mater 2023, 2: 100133.
[196]
Liu SB, Liu QX, Luo JL. CO2-to-CO conversion on layered perovskite with in situ exsolved Co–Fe alloy nanoparticles: An active and stable cathode for solid oxide electrolysis cells. J Mater Chem A 2016, 4: 17521–17528.
[197]
Cho A, Ko J, Kim BK, et al. Electrocatalysts with increased activity for coelectrolysis of steam and carbon dioxide in solid oxide electrolyzer cells. ACS Catal 2019, 9: 967–976.
[198]
Zhu CL, Hou LX, Li SS, et al. Efficient carbon dioxide electrolysis with metal nanoparticles loaded La0.75Sr0.25Cr0.5Mn0.5O3−δ cathodes. J Power Sources 2017, 363: 177–184.
[199]
Zhang XM, Song YF, Guan F, et al. Enhancing electrocatalytic CO2 reduction in solid oxide electrolysis cell with Ce0.9Mn0.1O2−δ nanoparticles-modified LSCM–GDC cathode. J Catal 2018, 359: 8–16.
[200]
Lee S, Woo SH, Shin TH, et al. Pd and GDC co-infiltrated LSCM cathode for high-temperature CO2 electrolysis using solid oxide electrolysis cells. Chem Eng J 2021, 420: 127706.
[201]
Xing RM, Wang YR, Zhu YQ, et al. Co-electrolysis of steam and CO2 in a solid oxide electrolysis cell with La0.75Sr0.25Cr0.5Mn0.5O3−δ–Cu ceramic composite electrode. J Power Sources 2015, 274: 260–264.
[202]
Lv HF, Zhou YJ, Zhang XM, et al. Infiltration of Ce0.8Gd0.2O1.9 nanoparticles on Sr2Fe1.5Mo0.5O6−δ cathode for CO2 electroreduction in solid oxide electrolysis cell. J Energy Chem 2019, 35: 71–78.
[203]
Xu SS, Li SS, Yao WT, et al. Direct electrolysis of CO2 using an oxygen-ion conducting solid oxide electrolyzer based on La0.75Sr0.25Cr0.5Mn0.5O3−δ electrode. J Power Sources 2013, 230: 115–121.
[204]
Liu SB, Liu QX, Luo JL. The excellence of La(Sr)Fe(Ni)O3 as an active and efficient cathode for direct CO2 electrochemical reduction at elevated temperatures. J Mater Chem A 2017, 5: 2673–2680.
[205]
Addo PK, Molero-Sanchez B, Chen M, et al. CO/CO2 study of high performance La0.3Sr0.7Fe0.7Cr0.3O3−δ reversible SOFC electrodes. Fuel Cells 2015, 15: 689–696.
[206]
Hu SQ, Zhang LX, Cao ZW, et al. Cathode activation process and CO2 electroreduction mechanism on LnFeO3−δ (Ln = La, Pr and Gd) perovskite cathodes. J Power Sources 2021, 485: 229343.
[207]
Xi XA, Liu JW, Fan Y, et al. Reducing d–p band coupling to enhance CO2 electrocatalytic activity by Mg-doping in Sr2FeMoO6−δ double perovskite for high performance solid oxide electrolysis cells. Nano Energy 2021, 82: 105707.
[208]
Zhang YQ, Li JH, Sun YF, et al. Highly active and redox-stable Ce-doped LaSrCrFeO-based cathode catalyst for CO2 SOECs. ACS Appl Mater Interfaces 2016, 8: 6457–6463.
[209]
Ye LT, Zhang MY, Huang P, et al. Enhancing CO2 electrolysis through synergistic control of non-stoichiometry and doping to tune cathode surface structures. Nat Commun 2017, 8: 14785.
[210]
Yang XX, Sun W, Ma MJ, et al. Achieving highly efficient carbon dioxide electrolysis by in situ construction of the heterostructure. ACS Appl Mater Interfaces 2021, 13: 20060–20069.
[211]
Choi J, Park S, Han H, et al. Highly efficient CO2 electrolysis to CO on Ruddlesden–Popper perovskite oxide with in situ exsolved Fe nanoparticles. J Mater Chem A 2021, 9: 8740–8748.
[212]
Liu CY, Li ST, Gao JQ, et al. Enhancing CO2 catalytic adsorption on an Fe nanoparticle-decorated LaSrFeO4+δ cathode for CO2 electrolysis. ACS Appl Mater Interfaces 2021, 13: 8229–8238.
[213]
Sun YF, Zhang YQ, Chen J, et al. New opportunity for in situ exsolution of metallic nanoparticles on perovskite parent. Nano Lett 2016, 16: 5303–5309.
[214]
Lv HF, Liu TF, Zhang XM, et al. Atomic-scale insight into exsolution of CoFe alloy nanoparticles in La0.4Sr0.6Co0.2Fe0.7Mo0.1O3−δ with efficient CO2 electrolysis. Angew Chem Int Ed 2020, 59: 15968–15973.
[215]
Park S, Kim Y, Noh Y, et al. A sulfur-tolerant cathode catalyst fabricated with in situ exsolved CoNi alloy nanoparticles anchored on a Ruddlesden–Popper support for CO2 electrolysis. J Mater Chem A 2020, 8: 138–148.
[216]
Wang SJ, Tsuruta H, Asanuma M, et al. Ni–Fe–La(Sr)Fe(Mn)O3 as a new active cermet cathode for intermediate-temperature CO2 electrolysis using a LaGaO3-based electrolyte. Adv Energy Mater 2015, 5: 1401003.
[217]
Liu SB, Liu QX, Luo JL. Highly stable and efficient catalyst with in situ exsolved Fe–Ni alloy nanospheres socketed on an oxygen deficient perovskite for direct CO2 electrolysis. ACS Catal 2016, 6: 6219–6228.
[218]
Li YH, Hu BB, Xia CR, et al. A novel fuel electrode enabling direct CO2 electrolysis with excellent and stable cell performance. J Mater Chem A 2017, 5: 20833–20842.
[219]
Laguna-Bercero MA, Campana R, Larrea A, et al. Electrolyte degradation in anode supported microtubular yttria stabilized zirconia-based solid oxide steam electrolysis cells at high voltages of operation. J Power Sources 2011, 196: 8942–8947.
[220]
Laguna-Bercero MA, Campana R, Larrea A, et al. Performance and aging of microtubular YSZ-based solid oxide regenerative fuel cells. Fuel Cells 2011, 11: 116–123.
[221]
Knibbe R, Traulsen ML, Hauch A, et al. Solid oxide electrolysis cells: Degradation at high current densities. J Electrochem Soc 2010, 157: B1209–B1217.
[222]
Chen KF, Jiang SP. Review—Materials degradation of solid oxide electrolysis cells. J Electrochem Soc 2016, 163: F3070–F3083.
[223]
Chen KF, Jiang SP. Failure mechanism of (La,Sr)MnO3 oxygen electrodes of solid oxide electrolysis cells. Int J Hydrogen Energ 2011, 36: 10541–10549.
[224]
Laguna-Bercero MA, Orera VM. Micro-spectroscopic study of the degradation of scandia and ceria stabilized zirconia electrolytes in solid oxide electrolysis cells. Int J Hydrogen Energ 2011, 36: 13051–13058.
[225]
Omar S, Belda A, Escardino A, et al. Ionic conductivity ageing investigation of 1Ce10ScSZ in different partial pressures of oxygen. Solid State Ionics 2011, 184: 2–5.
[226]
De Vero JC, Develos-Bagarinao K, Kishimoto H, et al. Effect of cathodic polarization on the La0.6Sr0.4Co0.2Fe0.8O3−δ-cathode/Gd-doped ceria-interlayer/YSZ electrolyte interfaces of solid oxide fuel cells. J Electrochem Soc 2017, 164: F259–F269.
[227]
Kim SJ, Kim KJ, Choi GM. Effect of Ce0.43Zr0.43Gd0.1Y0.04O2−δ contact layer on stability of interface between GDC interlayer and YSZ electrolyte in solid oxide electrolysis cell. J Power Sources 2015, 284: 617–622.
[228]
Tietz F, Sebold D, Brisse A, et al. Degradation phenomena in a solid oxide electrolysis cell after 9000 h of operation. J Power Sources 2013, 223: 129–135.
[229]
Fan H, Keane M, Singh P, et al. Electrochemical performance and stability of lanthanum strontium cobalt ferrite oxygen electrode with gadolinia doped ceria barrier layer for reversible solid oxide fuel cell. J Power Sources 2014, 268: 634–639.
[230]
Virkar AV, Nachlas J, Joshi AV, et al. Internal precipitation of molecular oxygen and electromechanical failure of zirconia solid electrolytes. J Am Ceram Soc 1990, 73: 3382–3390.
[231]
Mawdsley JR, Carter JD, Kropf AJ, et al. Post-test evaluation of oxygen electrodes from solid oxide electrolysis stacks. Int J Hydrogen Energ 2009, 34: 4198–4207.
[232]
Jacobsen T, Mogensen M. The course of oxygen partial pressure and electric potentials across an oxide electrolyte cell. ECS Trans 2008, 13: 259–273.
[233]
Zhang YX, Chen KF, Xia CR, et al. A model for the delamination kinetics of La0.8Sr0.2MnO3 oxygen electrodes of solid oxide electrolysis cells. Int J Hydrogen Energ 2012, 37: 13914–13920.
[234]
Rashkeev SN, Glazoff MV. Atomic-scale mechanisms of oxygen electrode delamination in solid oxide electrolyzer cells. Int J Hydrogen Energ 2012, 37: 1280–1291.
[235]
Laguna-Bercero MA, Kilner JA, Skinner SJ. Performance and characterization of (La,Sr)MnO3/YSZ and La0.6Sr0.4Co0.2Fe0.8O3 electrodes for solid oxide electrolysis cells. Chem Mater 2010, 22: 1134–1141.
[236]
Mahata A, Datta P, Basu RN. Microstructural and chemical changes after high temperature electrolysis in solid oxide electrolysis cell. J Alloys Compd 2015, 627: 244–250.
[237]
Chen KF, Ai N, Jiang SP. Performance and stability of (La,Sr)MnO3–Y2O3–ZrO2 composite oxygen electrodes under solid oxide electrolysis cell operation conditions. Int J Hydrogen Energ 2012, 37: 10517–10525.
[238]
Keane M, Mahapatra MK, Verma A, et al. LSM–YSZ interactions and anode delamination in solid oxide electrolysis cells. Int J Hydrogen Energ 2012, 37: 16776–16785.
[239]
Ai N, He S, Li N, et al. Suppressed Sr segregation and performance of directly assembled La0.6Sr0.4Co0.2Fe0.8O3−δ oxygen electrode on Y2O3–ZrO2 electrolyte of solid oxide electrolysis cells. J Power Sources 2018, 384: 125–135.
[240]
Pan ZH, Liu QL, Ni M, et al. Activation and failure mechanism of La0.6Sr0.4Co0.2Fe0.8O3−δ air electrode in solid oxide electrolyzer cells under high-current electrolysis. Int J Hydrogen Energ 2018, 43: 5437–5450.
[241]
Al Daroukh M, Tietz F, Sebold D, et al. Post-test analysis of electrode-supported solid oxide electrolyser cells. Ionics 2015, 21: 1039–1043.
[242]
Mahmoud A, Al Daroukh M, Lipinska-Chwalek M, et al. A Mössbauer spectral study of degradation in La0.58Sr0.4Fe0.5Co0.5O3−x after long-term operation in solid oxide electrolysis cells. Solid State Ionics 2017, 312: 38–43.
[243]
The D, Grieshammer S, Schroeder M, et al. Microstructural comparison of solid oxide electrolyser cells operated for 6100 h and 9000 h. J Power Sources 2015, 275: 901–911.
[244]
Zheng YF, Li QS, Chen T, et al. Comparison of performance and degradation of large-scale solid oxide electrolysis cells in stack with different composite air electrodes. Int J Hydrogen Energ 2015, 40: 2460–2472.
[245]
Kim-Lohsoontorn P, Brett DJL, Laosiripojana N, et al. Performance of solid oxide electrolysis cells based on composite La0.8Sr0.2MnO3−δ–yttria stabilized zirconia and Ba0.5Sr0.5Co0.8Fe0.2O3−δ oxygen electrodes. Int J Hydrogen Energ 2010, 35: 3958–3966.
[246]
Aphale A, Liang CY, Hu BX, et al. Cathode degradation from airborne contaminants in solid oxide fuel cells: A review. In: Solid Oxide Fuel Cell Lifetime and Reliability. Brandon NP, Ruiz-Trejo E, Boldrin P, Eds. London, UK: Academic Press, 2017: 101–119.
DOI
[247]
Hilpert K, Das D, Miller M, et al. Chromium vapor species over solid oxide fuel cell interconnect materials and their potential for degradation processes. J Electrochem Soc 1996, 143: 3642–3647.
[248]
Falk-Windisch H, Svensson JE, Froitzheim J. The effect of temperature on chromium vaporization and oxide scale growth on interconnect steels for Solid Oxide Fuel Cells. J Power Sources 2015, 287: 25–35.
[249]
Pei K, Zhou YC, Xu K, et al. Enhanced Cr-tolerance of an SOFC cathode by an efficient electro-catalyst coating. Nano Energy 2020, 72: 104704.
[250]
Niu YH, Zhou YC, Lv WQ, et al. Enhancing oxygen reduction activity and Cr tolerance of solid oxide fuel cell cathodes by a multiphase catalyst coating. Adv Funct Mater 2021, 31: 2100034.
[251]
Chen Y, Yoo S, Li XX, et al. An effective strategy to enhancing tolerance to contaminants poisoning of solid oxide fuel cell cathodes. Nano Energy 2018, 47: 474–480.
[252]
Taniguchi S, Kadowaki M, Kawamura H, et al. Degradation phenomena in the cathode of a solid oxide fuel cell with an alloy separator. J Power Sources 1995, 55: 73–79.
[253]
Li J, Yan D, Zhang WY, et al. The investigation of Cr deposition and poisoning effect on Sr-doped lanthanum manganite cathode induced by cathodic polarization for intermediate temperature solid oxide fuel cell. Electrochim Acta 2017, 255: 31–40.
[254]
Jiang SP, Zhang JP, Foger K. Deposition of chromium species at Sr-doped LaMnO3 electrodes in solid oxide fuel cells II. Effect on O2 reduction reaction. J Electrochem Soc 2000, 147: 3195–3205.
[255]
Jiang SP, Zhang JP, Apateanu L, et al. Deposition of chromium species at Sr-doped LaMnO3 electrodes in solid oxide fuel cells. I. Mechanism and kinetics. J Electrochem Soc 2000, 147: 4013–4022.
[256]
Jiang SP, Zhang JP, Foger K. Deposition of chromium species at Sr-doped LaMnO3 electrodes in solid oxide fuel cells: III. Effect of air flow. J Electrochem Soc 2001, 148: C447–C455.
[257]
Horita T, Xiong YP, Yoshinaga M, et al. Determination of chromium concentration in solid oxide fuel cell cathodes: (La,Sr)MnO3 and (La,Sr)FeO3. Electrochem Solid-State Lett 2009, 12: B146–B149.
[258]
Horita T, Xiong YP, Kishimoto H, et al. Chromium poisoning and degradation at (La,Sr)MnO3 and (La,Sr)FeO3 cathodes for solid oxide fuel cells. J Electrochem Soc 2010, 157: B614–B620.
[259]
Badwal SPS, Deller R, Foger K, et al. Interaction between chromia forming alloy interconnects and air electrode of solid oxide fuel cells. Solid State Ionics 1997, 99: 297–310.
[260]
Ni N, Wang CC, Jiang SP, et al. Synergistic effects of temperature and polarization on Cr poisoning of La0.6Sr0.4Co0.2Fe0.8O3−δ solid oxide fuel cell cathodes. J Mater Chem A 2019, 7: 9253–9262.
[261]
Qiu P, Li J, Jia LC, et al. LaCoO3−δ coated Ba0.5Sr0.5Co0.8Fe0.2O3−δ cathode for intermediate temperature solid oxide fuel cells. Electrochim Acta 2019, 319: 981–989.
[262]
Qiu P, Lin J, Lei LB, et al. Evaluation of Cr-tolerance of the Sr2Fe1.5Mo0.5O6−δ cathode for solid oxide fuel cells. ACS Appl Energy Mater 2019, 2: 7619–7627.
[263]
Wang JL, Yang ZB, Yang KC, et al. Chromium deposition and poisoning on Ba0.9Co0.7Fe0.2Nb0.1O3−δ cathode of solid oxide fuel cells. Electrochim Acta 2018, 289: 503–515.
[264]
Konysheva E, Penkalla H, Wessel E, et al. Chromium poisoning of perovskite cathodes by the ODS alloy Cr5Fe1Y2O3 and the high chromium ferritic steel Crofer22APU. J Electrochem Soc 2006, 153: A765–A773.
[265]
Qiu P, Yang X, Zou L, et al. LaCrO3-coated La0.6Sr0.4Co0.2Fe0.8O3−δ core–shell structured cathode with enhanced Cr tolerance for intermediate-temperature solid oxide fuel cells. ACS Appl Mater Interfaces 2020, 12: 29133–29142.
[266]
Xiong CY, Taillon JA, Pellegrinelli C, et al. Long-term Cr poisoning effect on LSCF–GDC composite cathodes sintered at different temperatures. J Electrochem Soc 2016, 163: F1091–F1099.
[267]
Wongpromrat W, Berthomé G, Parry V, et al. Reduction of chromium volatilisation from stainless steel interconnector of solid oxide electrochemical devices by controlled preoxidation. Corros Sci 2016, 106: 172–178.
[268]
Mah JCW, Muchtar A, Somalu MR, et al. Metallic interconnects for solid oxide fuel cell: A review on protective coating and deposition techniques. Int J Hydrogen Energ 2017, 42: 9219–9229.
[269]
Yang ZG, Xia GG, Li XH, et al. (Mn,Co)3O4 spinel coatings on ferritic stainless steels for SOFC interconnect applications. Int J Hydrogen Energ 2007, 32: 3648–3654.
[270]
Komatsu T, Arai H, Chiba R, et al. Cr poisoning suppression in solid oxide fuel cells using LaNi(Fe)O3 electrodes. Electrochem Solid-State Lett 2006, 9: A9–A12.
[271]
Zhen YD, Tok AIY, Jiang SP, et al. La(Ni,Fe)O3 as a cathode material with high tolerance to chromium poisoning for solid oxide fuel cells. J Power Sources 2007, 170: 61–66.
[272]
Yang M, Bucher E, Sitte W. Effects of chromium poisoning on the long-term oxygen exchange kinetics of the solid oxide fuel cell cathode materials La0.6Sr0.4CoO3 and Nd2NiO4. J Power Sources 2011, 196: 7313–7317.
[273]
Chen XB, Jiang SP. Highly active and stable (La0.24Sr0.16Ba0.6)(Co0.5Fe0.44Nb0.06)O3−δ (LSBCFN) cathodes for solid oxide fuel cells prepared by a novel mixing synthesis method. J Mater Chem A 2013, 1: 4871–4878.
[274]
Zhao L, Cheng Y, Jiang SP. A new, high electrochemical activity and chromium tolerant cathode for solid oxide fuel cells. Int J Hydrogen Energ 2015, 40: 15622–15631.
[275]
Yan AY, Liu B, Dong YL, et al. A temperature programmed desorption investigation on the interaction of Ba0.5Sr0.5Co0.8Fe0.2O3−δ perovskite oxides with CO2 in the absence and presence of H2O and O2. Appl Catal B-Environ 2008, 80: 24–31.
[276]
Yu Y, Luo H, Cetin D, et al. Effect of atmospheric CO2 on surface segregation and phase formation in La0.6Sr0.4Co0.2Fe0.8O3−δ thin films. Appl Surf Sci 2014, 323: 71–77.
[277]
Zhang Y, Yang GM, Chen G, et al. Evaluation of the CO2 poisoning effect on a highly active cathode SrSc0.175Nb0.025Co0.8O3−δ in the oxygen reduction reaction. ACS Appl Mater Interfaces 2016, 8: 3003–3011.
[278]
Wang JL, Yang ZB, Ba LM, et al. Effects of CO2 and H2O on Ba0.9Co0.7Fe0.2Nb0.1O3−δ cathode and modification by a Ce0.9Gd0.1O2−δ coating. J Electroanal Chem 2018, 827: 79–84.
[279]
Li M, Niu HJ, Druce J, et al. A CO2-tolerant perovskite oxide with high oxide ion and electronic conductivity. Adv Mater 2020, 32: 1905200.
[280]
Ding XF, Gao ZP, Ding D, et al. Cation deficiency enabled fast oxygen reduction reaction for a novel SOFC cathode with promoted CO2 tolerance. Appl Catal B-Environ 2019, 243: 546–555.
[281]
Lu Y, Zhao XY, Wang ZH, et al. Trade-off between oxygen reduction reaction activity and CO2 stability in a cation doped Ba0.9Co0.7Fe0.3O3−δ perovskite cathode for solid oxide fuel cells. Sustainable Energy Fuels 2020, 4: 5229–5237.
[282]
Ding D, Li XX, Lai SY, et al. Enhancing SOFC cathode performance by surface modification through infiltration. Energ Environ Sci 2014, 7: 552–575.
[283]
Qiu P, Wang A, Zheng HY, et al. LaCoO3−δ-coated Ba0.5Sr0.5Co0.8Fe0.2O3−δ: A promising cathode material with remarkable performance and CO2 resistance for intermediate temperature solid oxide fuel cells. Int J Hydrogen Energ 2018, 43: 20696–20703.
[284]
Wang CC, He S, Chen KF, et al. Effect of SO2 poisoning on the electrochemical activity of La0.6Sr0.4Co0.2Fe0.8O3−δ cathodes of solid oxide fuel cells. J Electrochem Soc 2017, 164: F514–F524.
[285]
Wang CC, Chen KF, Jiang SP. Mechanism and kinetics of SO2 poisoning on the electrochemical activity of La0.8Sr0.2MnO3 cathodes of solid oxide fuel cells. J Electrochem Soc 2016, 163: F771–F780.
[286]
Wang CC, Chen KF, Jiang T, et al. Sulphur poisoning of solid oxide electrolysis cell anodes. Electrochim Acta 2018, 269: 188–195.
[287]
Kushi T. Effects of sulfur poisoning on degradation phenomena in oxygen electrodes of solid oxide electrolysis cells and solid oxide fuel cells. Int J Hydrogen Energ 2017, 42: 9396–9405.
[288]
Chen KF, Hyodo J, Ai N, et al. Boron deposition and poisoning of La0.8Sr0.2MnO3 oxygen electrodes of solid oxide electrolysis cells under accelerated operation conditions. Int J Hydrogen Energ 2016, 41: 1419–1431.
[289]
Chen K, Ai N, Jiang SP. Chemical compatibility between boron oxides and electrolyte and cathode materials of solid oxide fuel cells. Fuel Cells 2013, 13: 1101–1108.
[290]
Holzer L, Iwanschitz B, Hocker T, et al. Microstructure degradation of cermet anodes for solid oxide fuel cells: Quantification of nickel grain growth in dry and in humid atmospheres. J Power Sources 2011, 196: 1279–1294.
[291]
Sehested J, Gelten JAP, Helveg S. Sintering of nickel catalysts: Effects of time, atmosphere, temperature, nickel-carrier interactions, and dopants. Appl Catal A-Gen 2006, 309: 237–246.
[292]
Osinkin DA, Kuzin BL, Bogdanovich NM. Effect of oxygen activity and water partial pressure to degradation rate of Ni cermet electrode contacting Zr0.84Y0.16O1.92 electrolyte. Russ J Electrochem 2010, 46: 41–48.
[293]
Hauch A, Ebbesen SD, Jensen SH, et al. Solid oxide electrolysis cells: Microstructure and degradation of the Ni/yttria-stabilized zirconia electrode. J Electrochem Soc 2008, 155: B1184–B1193.
[294]
Kim-Lohsoontorn P, Kim YM, Laosiripojana N, et al. Gadolinium doped ceria-impregnated nickel–yttria stabilised zirconia cathode for solid oxide electrolysis cell. Int J Hydrogen Energ 2011, 36: 9420–9427.
[295]
Keane M, Fan H, Han MF, et al. Role of initial microstructure on nickel–YSZ cathode degradation in solid oxide electrolysis cells. Int J Hydrogen Energ 2014, 39: 18718–18726.
[296]
Duboviks V, Lomberg M, Maher RC, et al. Carbon deposition behaviour in metal-infiltrated gadolinia doped ceria electrodes for simulated biogas upgrading in solid oxide electrolysis cells. J Power Sources 2015, 293: 912–921.
[297]
Shi YX, Luo Y, Cai NS, et al. Experimental characterization and modeling of the electrochemical reduction of CO2 in solid oxide electrolysis cells. Electrochim Acta 2013, 88: 644–653.
[298]
Tao YK, Ebbesen SD, Mogensen MB. Carbon deposition in solid oxide cells during co-electrolysis of H2O and CO2. J Electrochem Soc 2014, 161: F337–F343.
[299]
Yan JB, Chen H, Dogdibegovic E, et al. High-efficiency intermediate temperature solid oxide electrolyzer cells for the conversion of carbon dioxide to fuels. J Power Sources 2014, 252: 79–84.
[300]
Skafte TL, Guan ZX, Machala ML, et al. Selective high-temperature CO2 electrolysis enabled by oxidized carbon intermediates. Nat Energy 2019, 4: 846–855.
[301]
Xing RM, Wang YR, Liu SH, et al. Preparation and characterization of La0.75Sr0.25Cr0.5Mn0.5O3−δ–yttria stabilized zirconia cathode supported solid oxide electrolysis cells for hydrogen generation. J Power Sources 2012, 208: 276–281.
[302]
Xie K, Zhang YQ, Meng GY, et al. Direct synthesis of methane from CO2/H2O in an oxygen-ion conducting solid oxide electrolyser. Energ Environ Sci 2011, 4: 2218–2222.
[303]
Bernuy-Lopez C, Knibbe R, He ZM, et al. Electrochemical characterisation of solid oxide cell electrodes for hydrogen production. J Power Sources 2011, 196: 4396–4403.
[304]
Hauch A, Jensen SH, Bilde-Sørensen JB, et al. Silica segregation in the Ni/YSZ electrode. J Electrochem Soc 2007, 154: A619–A626.
[305]
Jacobson NS, Opila EJ, Myers DL, et al. Thermodynamics of gas phase species in the Si–O–H system. J Chem Thermodyn 2005, 37: 1130–1137.
[306]
Mahapatra MK, Lu K. Glass-based seals for solid oxide fuel and electrolyzer cells—A review. Mater Sci Eng R 2010, 67: 65–85.
[307]
O’Brien JE, Stoots CM, Herring JS, et al. The high-temperature electrolysis program at the Idaho National Laboratory: Observations on performance degradation. Idaho National Laboratory (INL), 2009.
[308]
Jeanmonod G, Diethelm S, Van Herle J. The effect of SO2 on the Ni–YSZ electrode of a solid oxide electrolyzer cell operated in co-electrolysis. J Phys Energy 2020, 2: 034002.
[309]
Skafte TL, Blennow P, Hjelm J, et al. Carbon deposition and sulfur poisoning during CO2 electrolysis in nickel-based solid oxide cell electrodes. J Power Sources 2018, 373: 54–60.
[310]
Zhang L, Jiang SP, He HQ, et al. A comparative study of H2S poisoning on electrode behavior of Ni/YSZ and Ni/GDC anodes of solid oxide fuel cells. Int J Hydrogen Energ 2010, 35: 12359–12368.
[311]
Riegraf M, Zekri A, Knipper M, et al. Sulfur poisoning of Ni/Gadolinium-doped ceria anodes: A long-term study outlining stable solid oxide fuel cell operation. J Power Sources 2018, 380: 26–36.
[312]
Mehran MT, Khan MZ, Lee SB, et al. Improving sulfur tolerance of Ni–YSZ anodes of solid oxide fuel cells by optimization of microstructure and operating conditions. Int J Hydrogen Energ 2018, 43: 11202–11213.
[313]
Jeanmonod G, Diethelm S, van herle J. Poisoning effects of chlorine on a solid oxide cell operated in co-electrolysis. J Power Sources 2021, 506: 230247.
[314]
Kreuer KD. Proton conductivity:  Materials and applications. Chem Mater 1996, 8: 610–641.
[315]
Fabbri E, Pergolesi D, Traversa E. Materials challenges toward proton-conducting oxide fuel cells: A critical review. Chem Soc Rev 2010, 39: 4355–4369.
[316]
Zhang Y, Knibbe R, Sunarso J, et al. Recent progress on advanced materials for solid-oxide fuel cells operating below 500 ℃. Adv Mater 2017, 29: 1700132.
[317]
Wang W, Medvedev D, Shao ZP. Gas humidification impact on the properties and performance of perovskite-type functional materials in proton-conducting solid oxide cells. Adv Funct Mater 2018, 28: 1802592.
[318]
Kreuer KD. Proton-conducting oxides. Annu Rev Mater Res 2003, 33: 333–359.
[319]
Hibino T, Mizutani K, Yajima T, et al. Evaluation of proton conductivity in SrCeO3, BaCeO3, CaZrO3 and SrZrO3 by temperature programmed desorption method. Solid State Ionics 1992, 57: 303–306.
[320]
Iwahara H, Uchida H, Ono K, et al. Proton conduction in sintered oxides based on BaCeO3. J Electrochem Soc 1988, 135: 529–533.
[321]
Malavasi L, Fisher CAJ, Islam MS. Oxide-ion and proton conducting electrolyte materials for clean energy applications: Structural and mechanistic features. Chem Soc Rev 2010, 39: 4370–4387.
[322]
Kim J, Sengodan S, Kim S, et al. Proton conducting oxides: A review of materials and applications for renewable energy conversion and storage. Renew Sust Energ Rev 2019, 109: 606–618.
[323]
Bohn HG, Schober T, Mono T, et al. The high temperature proton conductor Ba3Ca1.18Nb1.82O9−δ. I. Electrical conductivity. Solid State Ionics 1999, 117: 219–228.
[324]
Tsai CL, Schmidt VH. Fabrication, performance, and model for proton conductive solid oxide fuel cell. J Electrochem Soc 2011, 158: B885–B898.
[325]
Nowick AS, Du Y. High-temperature protonic conductors with perovskite-related structures. Solid State Ionics 1995, 77: 137–146.
[326]
Yang XF, Jia LC, Pan BC, et al. Mechanism of proton conduction in doped barium cerates: A first-principles study. J Phys Chem C 2020, 124: 8024–8033.
[327]
Somalu MR, Norman NW, Muchtar A. A short review on the proton conducting electrolytes for solid oxide fuel cell applications. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 2018, 52: 115–122.
[328]
Tanner CW, Virkar AV. Instability of BaCeO3 in  H2O-containing atmospheres. J Electrochem Soc 1996, 143: 1386–1389.
[329]
Bhide SV, Virkar AV. Stability of BaCeO3‐based proton conductors in water-containing atmospheres. J Electrochem Soc 1999, 146: 2038–2044.
[330]
Tong JH, Clark D, Bernau L, et al. Solid-state reactive sintering mechanism for large-grained yttrium-doped barium zirconate proton conducting ceramics. J Mater Chem 2010, 20: 6333–6341.
[331]
Sun WP, Yan LT, Shi Z, et al. Fabrication and performance of a proton-conducting solid oxide fuel cell based on a thin BaZr0.8Y0.2O3−δ electrolyte membrane. J Power Sources 2010, 195: 4727–4730.
[332]
Ricote S, Bonanos N, Manerbino A, et al. Effects of the fabrication process on the grain-boundary resistance in BaZr0.9Y0.1O3−δ. J Mater Chem A 2014, 2: 16107–16115.
[333]
Fabbri E, D’Epifanio A, Di Bartolomeo E, et al. Tailoring the chemical stability of Ba(Ce0.8−xZrx)Y0.2O3−δ protonic conductors for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Solid State Ionics 2008, 179: 558–564.
[334]
Yang L, Wang SZ, Blinn K, et al. Enhanced sulfur and coking tolerance of a mixed ion conductor for SOFCs: BaZr0.1Ce0.7Y0.2−xYbxO3−δ. Science 2009, 326: 126–129.
[335]
Duan CC, Kee R, Zhu HY, et al. Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production. Nat Energy 2019, 4: 230–240.
[336]
Wu W, Wang LC, Hu HQ, et al. Electrochemically engineered, highly energy-efficient conversion of ethane to ethylene and hydrogen below 550 ℃ in a protonic ceramic electrochemical cell. ACS Catal 2021, 11: 12194–12202.
[337]
Hua B, Yan N, Li M, et al. Novel layered solid oxide fuel cells with multiple-twinned Ni0.8Co0.2 nanoparticles: The key to thermally independent CO2 utilization and power-chemical cogeneration. Energ Environ Sci 2016, 9: 207–215.
[338]
Hua B, Yan N, Li M, et al. Anode-engineered protonic ceramic fuel cell with excellent performance and fuel compatibility. Adv Mater 2016, 28: 8922–8926.
[339]
Wu W, Ding HP, Zhang YY, et al. 3D self-architectured steam electrode enabled efficient and durable hydrogen production in a proton-conducting solid oxide electrolysis cell at temperatures lower than 600 ℃. Adv Sci 2018, 5: 1800370.
[340]
Duan CC, Tong JH, Shang M, et al. Readily processed protonic ceramic fuel cells with high performance at low temperatures. Science 2015, 349: 1321–1326.
[341]
Zhou R, Yin YR, Dai HL, et al. Attempted preparation of La0.5Ba0.5MnO3−δ leading to an in-situ formation of manganate nanocomposites as a cathode for proton-conducting solid oxide fuel cells. J Adv Ceram 2023, 12: 1189–1200.
[342]
Xu YS, Xu X, Bi L. A high-entropy spinel ceramic oxide as the cathode for proton-conducting solid oxide fuel cells. J Adv Ceram 2022, 11: 794–804.
[343]
Xu YS, Yu SF, Yin YR, et al. Taking advantage of Li-evaporation in LiCoO2 as cathode for proton-conducting solid oxide fuel cells. J Adv Ceram 2022, 11: 1849–1859.
[344]
He F, Song D, Peng RR, et al. Electrode performance and analysis of reversible solid oxide fuel cells with proton conducting electrolyte of BaCe0.5Zr0.3Y0.2O3−δ. J Power Sources 2010, 195: 3359–3364.
[345]
Huan DM, Wang WH, Xie Y, et al. Investigation of real polarization resistance for electrode performance in proton-conducting electrolysis cells. J Mater Chem A 2018, 6: 18508–18517.
[346]
Slodczyk A, Sharp MD, Upasen S, et al. Combined bulk and surface analysis of the BaCe0.5Zr0.3Y0.16Zn0.04O3−δ (BCZYZ) ceramic proton-conducting electrolyte. Solid State Ionics 2014, 262: 870–874.
[347]
Hakim M, Yoo CY, Joo JH, et al. Enhanced durability of a proton conducting oxide fuel cell with a purified yttrium-doped barium zirconate–cerate electrolyte. J Power Sources 2015, 278: 320–324.
[348]
Choi S, Kucharczyk CJ, Liang YG, et al. Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells. Nat Energy 2018, 3: 202–210.
[349]
Yoo CY, Yun DS, Joo JH, et al. The effects of NiO addition on the structure and transport properties of proton conducting BaZr0.8Y0.2O3−δ. J Alloys Compd 2015, 621: 263–267.
[350]
Sun ZQ, Fabbri E, Bi L, et al. Lowering grain boundary resistance of BaZr0.8Y0.2O3−δ with LiNO3 sintering-aid improves proton conductivity for fuel cell operation. Phys Chem Chem Phys 2011, 13: 7692–7700.
[351]
Tao SW, Irvine JTS. A stable, easily sintered proton-conducting oxide electrolyte for moderate-temperature fuel cells and electrolyzers. Adv Mater 2006, 18: 1581–1584.
[352]
Han DL, Uemura S, Hiraiwa C, et al. Detrimental effect of sintering additives on conducting ceramics: Yttrium-doped barium zirconate. ChemSusChem 2018, 11: 4102–4113.
[353]
Zhu HY, Ricote S, Kee RJ. Faradaic efficiency in protonic-ceramic electrolysis cells. J Phys Energy 2022, 4: 014002.
[354]
Fabbri E, Bi L, Tanaka H, et al. Chemically stable Pr and Y co-doped barium zirconate electrolytes with high proton conductivity for intermediate-temperature solid oxide fuel cells. Adv Funct Mater 2011, 21: 158–166.
[355]
Sun WP, Shi Z, Liu MF, et al. An easily sintered, chemically stable, barium zirconate-based proton conductor for high-performance proton-conducting solid oxide fuel cells. Adv Funct Mater 2014, 24: 5695–5702.
[356]
Liu Y, Guo YM, Ran R, et al. A new neodymium-doped BaZr0.8Y0.2O3−δ as potential electrolyte for proton-conducting solid oxide fuel cells. J Membrane Sci 2012, 415–416: 391–398.
[357]
Sun WP, Liu MF, Liu W. Chemically stable yttrium and tin co-doped barium zirconate electrolyte for next generation high performance proton-conducting solid oxide fuel cells. Adv Energy Mater 2013, 3: 1041–1050.
[358]
Xu X, Bi L, Zhao XS. Highly-conductive proton-conducting electrolyte membranes with a low sintering temperature for solid oxide fuel cells. J Membrane Sci 2018, 558: 17–25.
[359]
Pergolesi D, Fabbri E, D’Epifanio A, et al. High proton conduction in grain-boundary-free yttrium-doped barium zirconate films grown by pulsed laser deposition. Nat Mater 2010, 9: 846–852.
[360]
Shim JH, Gür TM, Prinz FB. Proton conduction in thin film yttrium-doped barium zirconate. Appl Phys Lett 2008, 92: 253115.
[361]
Bi L, Fabbri E, Sun ZQ, et al. A novel ionic diffusion strategy to fabricate high-performance anode-supported solid oxide fuel cells (SOFCs) with proton-conducting Y-doped BaZrO3 films. Energ Environ Sci 2011, 4: 409–412.
[362]
Choi S, Davenport TC, Haile SM. Protonic ceramic electrochemical cells for hydrogen production and electricity generation: Exceptional reversibility, stability, and demonstrated faradaic efficiency. Energ Environ Sci 2019, 12: 206–215.
[363]
Kobayashi T, Kuroda K, Jeong S, et al. Analysis of the anode reaction of solid oxide electrolyzer cells with BaZr0.4Ce0.4Y0.2O3−δ electrolytes and Sm0.5Sr0.5CoO3−δ anodes. J Electrochem Soc 2018, 165: F342–F349.
[364]
Iwahara H, Esaka T, Uchida H, et al. Proton conduction in sintered oxides and its application to steam electrolysis for hydrogen production. Solid State Ionics 1981, 3–4: 359–363.
[365]
Matsumoto H, Sakai T, Okuyama Y. Proton-conducting oxide and applications to hydrogen energy devices. Pure Appl Chem 2012, 85: 427–435.
[366]
Wang RF, Byrne C, Tucker MC. Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells. Solid State Ionics 2019, 332: 25–33.
[367]
Bi L, Shafi SP, Traversa E. Y-doped BaZrO3 as a chemically stable electrolyte for proton-conducting solid oxide electrolysis cells (SOECs). J Mater Chem A 2015, 3: 5815–5819.
[368]
Lei LB, Tao ZT, Wang XM, et al. Intermediate-temperature solid oxide electrolysis cells with thin proton-conducting electrolyte and a robust air electrode. J Mater Chem A 2017, 5: 22945–22951.
[369]
Li SS, Xie K. Composite oxygen electrode based on LSCF and BSCF for steam electrolysis in a proton-conducting solid oxide electrolyzer. J Electrochem Soc 2013, 160: F224–F233.
[370]
Kim J, Jun A, Gwon O, et al. Hybrid-solid oxide electrolysis cell: A new strategy for efficient hydrogen production. Nano Energy 2018, 44: 121–126.
[371]
Yin YR, Zhou YB, Gu YY, et al. Successful preparation of BaCo0.5Fe0.5O3−δ cathode oxide by rapidly cooling allowing for high-performance proton-conducting solid oxide fuel cells. J Adv Ceram 2023, 12: 587–597.
[372]
Zhao Z, Liu L, Zhang XM, et al. High- and low-temperature behaviors of La0.6Sr0.4Co0.2Fe0.8O3−δ cathode operating under CO2/H2O-containing atmosphere. Int J Hydrogen Energ 2013, 38: 15361–15370.
[373]
Bausá N, Solís C, Strandbakke R, et al. Development of composite steam electrodes for electrolyzers based on barium zirconate. Solid State Ionics 2017, 306: 62–68.
[374]
Huan DM, Shi N, Zhang L, et al. New, efficient, and reliable air electrode material for proton-conducting reversible solid oxide cells. ACS Appl Mater Interfaces 2018, 10: 1761–1770.
[375]
Shi N, Xie Y, Huan DM, et al. Controllable CO2 conversion in high performance proton conducting solid oxide electrolysis cells and the possible mechanisms. J Mater Chem A 2019, 7: 4855–4864.
[376]
Yang SJ, Zhang SP, Sun C, et al. Lattice incorporation of Cu2+ into the BaCe0.7Zr0.1Y0.1Yb0.1O3−δ electrolyte on boosting its sintering and proton-conducting abilities for reversible solid oxide cells. ACS Appl Mater Interfaces 2018, 10: 42387–42396.
[377]
Sun C, Yang SJ, Lu Y, et al. Tailoring a micro-nanostructured electrolyte–oxygen electrode interface for proton-conducting reversible solid oxide cells. J Power Sources 2020, 449: 227498.
[378]
Vøllestad E, Strandbakke R, Tarach M, et al. Mixed proton and electron conducting double perovskite anodes for stable and efficient tubular proton ceramic electrolysers. Nat Mater 2019, 18: 752–759.
[379]
Lyagaeva J, Danilov N, Vdovin G, et al. A new Dy-doped BaCeO3–BaZrO3 proton-conducting material as a promising electrolyte for reversible solid oxide fuel cells. J Mater Chem A 2016, 4: 15390–15399.
[380]
Li WY, Guan B, Ma L, et al. High performing triple-conductive Pr2NiO4+δ anode for proton-conducting steam solid oxide electrolysis cell. J Mater Chem A 2018, 6: 18057–18066.
[381]
Hui Z, Michèle P. Preparation, chemical stability, and electrical properties of Ba(Ce1−xBix)O3 (x = 0.0–0.5). J Mater Chem 2002, 12: 3787–3791.
[382]
Fabbri E, Bi L, Pergolesi D, et al. High-performance composite cathodes with tailored mixed conductivity for intermediate temperature solid oxide fuel cells using proton conducting electrolytes. Energ Environ Sci 2011, 4: 4984–4993.
[383]
Fabbri E, Oh TK, Licoccia S, et al. Mixed protonic/electronic conductor cathodes for intermediate temperature SOFCs based on proton conducting electrolytes. J Electrochem Soc 2009, 156: B38–B45.
[384]
Mukundan R, Davies PK, Worrell WL. Electrochemical characterization of mixed conducting Ba(Ce0.8−yPryGd0.2)O2.9 cathodes. J Electrochem Soc 2001, 148: A82–A86.
[385]
Grimaud A, Mauvy F, Bassat JM, et al. Hydration properties and rate determining steps of the oxygen reduction reaction of perovskite-related oxides as H+-SOFC cathodes. J Electrochem Soc 2012, 159: B683–B694.
[386]
Wang N, Toriumi H, Sato Y, et al. La0.8Sr0.2Co1−xNixO3−δ as the efficient triple conductor air electrode for protonic ceramic cells. ACS Appl Energy Mater 2021, 4: 554–563.
[387]
Ding HP, Wu W, Jiang C, et al. Self-sustainable protonic ceramic electrochemical cells using a triple conducting electrode for hydrogen and power production. Nat Commun 2020, 11: 1907.
[388]
Ren RZ, Sun JX, Wang GG, et al. Rational design of Sr2Fe1.5Mo0.4Y0.1O6−δ oxygen electrode with triple conduction for hydrogen production in protonic ceramic electrolysis cell. Sep Purif Technol 2022, 299: 121780.
[389]
Grimaud A, Mauvy F, Bassat JM, et al. Hydration and transport properties of the Pr2−xSrxNiO4+δ compounds as H+-SOFC cathodes. J Mater Chem 2012, 22: 16017–16025.
[390]
Danilov N, Lyagaeva J, Vdovin G, et al. Electricity/hydrogen conversion by the means of a protonic ceramic electrolysis cell with Nd2NiO4+δ-based oxygen electrode. Energ Convers Manage 2018, 172: 129–137.
[391]
Li WY, Guan B, Yang T, et al. Layer-structured triple-conducting electrocatalyst for water-splitting in protonic ceramic electrolysis cells: Conductivities vs. activity. J Power Sources 2021, 495: 229764.
[392]
Tian HC, Li WY, Ma L, et al. Deconvolution of water-splitting on the triple-conducting Ruddlesden–Popper-phase anode for protonic ceramic electrolysis cells. ACS Appl Mater Interfaces 2020, 12: 49574–49585.
[393]
Yang SJ, Wen YB, Zhang JC, et al. Electrochemical performance and stability of cobalt-free Ln1.2Sr0.8NiO4 (Ln = La and Pr) air electrodes for proton-conducting reversible solid oxide cells. Electrochim Acta 2018, 267: 269–277.
[394]
Xia YP, Xu X, Teng Y, et al. A novel BaFe0.8Zn0.1Bi0.1O3−δ cathode for proton conducting solid oxide fuel cells. Ceram Int 2020, 46: 25453–25459.
[395]
Wu S, Liu YH, Wang C, et al. Cobalt-free LaNi0.4Zn0.1Fe0.5O3−δ as a cathode for solid oxide fuel cells using proton-conducting electrolyte. Int J Hydrogen Energ 2021, 46: 38482–38489.
[396]
Xu X, Xu YS, Ma JM, et al. Tailoring electronic structure of perovskite cathode for proton-conducting solid oxide fuel cells with high performance. J Power Sources 2021, 489: 229486.
[397]
Muñoz-García AB, Pavone M. First-principles design of new electrodes for proton-conducting solid-oxide electrochemical cells: A-site doped Sr2Fe1.5Mo0.5O6−δ perovskite. Chem Mater 2016, 28: 490–500.
[398]
Muñoz-García AB, Pavone M. K-doped Sr2Fe1.5Mo0.5O6−δ predicted as a bifunctional catalyst for air electrodes in proton-conducting solid oxide electrochemical cells. J Mater Chem A 2017, 5: 12735–12739.
[399]
Yang Y, Shi N, Xie Y, et al. K doping as a rational method to enhance the sluggish air-electrode reaction kinetics for proton-conducting solid oxide cells. Electrochim Acta 2021, 389: 138453.
[400]
Zhu K, Yang Y, Huan DM, et al. Theoretical and experimental investigations on K-doped SrCo0.9Nb0.1O3−δ as a promising cathode for proton-conducting solid oxide fuel cells. ChemSusChem 2021, 14: 3876–3886.
[401]
Liu B, Li ZB, Yang XW, et al. Novel mixed H+/e/O2− conducting cathode material PrBa0.9K0.1Fe1.9Zn0.1O5+δ for proton-conducting solid oxide fuel cells. J Mater Chem A 2022, 10: 17425–17433.
[402]
Qiu P, Liu B, Wu L, et al. K-doped BaCo0.4Fe0.4Zr0.2O3−δ as a promising cathode material for protonic ceramic fuel cells. J Adv Ceram 2022, 11: 1988–2000.
[403]
Ge L, Verma A, Goettler R, et al. Oxide scale morphology and chromium evaporation characteristics of alloys for balance of plant applications in solid oxide fuel cells. Metall Mater Trans A 2013, 44: 193–206.
[404]
Yoo Y, Lim N. Performance and stability of proton conducting solid oxide fuel cells based on yttrium-doped barium cerate–zirconate thin-film electrolyte. J Power Sources 2013, 229: 48–57.
[405]
Gan Y, Zhang J, Li YX, et al. Composite oxygen electrode based on LSCM for steam electrolysis in a proton conducting solid oxide electrolyzer. J Electrochem Soc 2012, 159: F763–F767.
[406]
Leonard K, Okuyama Y, Takamura Y, et al. Efficient intermediate-temperature steam electrolysis with Y:SrZrO3–SrCeO3 and Y:BaZrO3–BaCeO3 proton conducting perovskites. J Mater Chem A 2018, 6: 19113–19124.
[407]
Rao YY, Zhong SH, He F, et al. Cobalt-doped BaZrO3: A single phase air electrode material for reversible solid oxide cells. Int J Hydrogen Energ 2012, 37: 12522–12527.
[408]
Yang SJ, Lu Y, Wang Q, et al. Effects of porous support microstructure enabled by the carbon microsphere pore former on the performance of proton-conducting reversible solid oxide cells. Int J Hydrogen Energ 2018, 43: 20050–20058.
[409]
Lee JI, Park KY, Park H, et al. Triple perovskite structured Nd1.5Ba1.5CoFeMnO9−δ oxygen electrode materials for highly efficient and stable reversible protonic ceramic cells. J Power Sources 2021, 510: 230409.
[410]
Xie K, Zhang YQ, Meng GY, et al. Electrochemical reduction of CO2 in a proton conducting solid oxide electrolyser. J Mater Chem 2011, 21: 195–198.
[411]
Pan ZH, Duan CC, Pritchard T, et al. High-yield electrochemical upgrading of CO2 into CH4 using large-area protonic ceramic electrolysis cells. Appl Catal B-Environ 2022, 307: 121196.
[412]
Tucker MC. Progress in metal-supported solid oxide fuel cells: A review. J Power Sources 2010, 195: 4570–4582.
[413]
Wu SH, Lin JK, Shiu WH, et al. Performance test for anode-supported and metal-supported solid oxide electrolysis cell under different current densities. In: Proceedings of the 42nd International Conference on Advanced Ceramics and Composites. Salem J, Koch D, Mechnich P, et al. Eds. Hoboken, USA: John Wiley & Sons, Inc., 2019: 139–148.
[414]
Ishihara T, Kusaba H, Kim HH, et al. Preparation of La0.9Sr0.1Ga0.8Mg0.2O3 film by pulse laser deposition (PLD) method on porous Ni–Fe metal substrate for CO2 electrolysis. ISIJ Int 2019, 59: 613–618.
[415]
Wang RF, Lau GY, Ding D, et al. Approaches for co-sintering metal-supported proton-conducting solid oxide cells with Ba(Zr,Ce,Y,Yb)O3−δ electrolyte. Int J Hydrogen Energ 2019, 44: 13768–13776.
Publication history
Copyright
Acknowledgements
Rights and permissions

Publication history

Received: 11 April 2023
Revised: 13 May 2023
Accepted: 16 May 2023
Published: 28 July 2023
Issue date: August 2023

Copyright

© The Author(s) 2023.

Acknowledgements

We acknowledge for the support by the National Key R&D Program of China (2018YFE0124700), the National Natural Science Foundation of China (52102279, 52072134, and 51972128), Natural Science Foundation of Shandong Province (ZR2021QE283), and Department of Science and Technology of Hubei Province (2021CBA149 and 2021CFA072).

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Return