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Polyoxometalates (POMs) have attracted extensive interests as solid-state proton conductors due to their high conductivity and good thermal stability. However, the low humidity stability and poor mechanical property of crystalline POMs greatly hinder their practical application. Herein, on the basis of the remarkable improvement of the humidity stability that can be achieved by hybridizing POMs with organic components, we prepared a new POM-based inorganic–organic hybrid, H[Zn(Hapca)3][PW12O40]·7H2O 1 (Hapca = 3-aminopyrazine-2-carboxylic acid), composed of Keggin-type PW12O403− anions and Zn(Hapca)32+ cations. Compound 1 exhibits a proton conductivity of 1.16 × 10−4 S·cm−1 at 55 °C, which remains stable at a relative humidity of 95%. To construct POM-based conductive materials with good mechanical property, we introduced 1 into a poly(vinyl alcohol) (PVA)/glycerol (Gly) hydrogel and obtained the hydrogel composites 1@PVA/Gly-x (x = 20%, 30%, and 40%, where x is the percentage of the mass of 1 to the total mass of 1 and PVA). Remarkably, the hydrogel composites 1@PVA/Gly-x combine the merits of their components. The proton conductivity of 1@PVA/Gly-40% reaches 1.11 × 10−2 S·cm−1 at ambient humidity and 75 °C, outperforming most POM-based composite materials reported to date. Moreover, 1@PVA/Gly-40% displays good elasticity and toughness and high strain sensitivity. Additionally, we assembled 1@PVA/Gly-40% into a strain sensor for the effective monitoring of various human activities. This work provides a new platform for the transformation of crystalline POM-based inorganic–organic hybrids into materials with good mechanical properties.


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Construction of hydrogel composites with superior proton conduction and flexibility using a new POM-based inorganic–organic hybrid

Show Author's information Yuxin WangYing Lu ( )Wensha ZhangTianyi DangYanli YangXue BaiShuxia Liu ( )
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education, College of Chemistry, Northeast Normal University, Changchun 130024, China

Abstract

Polyoxometalates (POMs) have attracted extensive interests as solid-state proton conductors due to their high conductivity and good thermal stability. However, the low humidity stability and poor mechanical property of crystalline POMs greatly hinder their practical application. Herein, on the basis of the remarkable improvement of the humidity stability that can be achieved by hybridizing POMs with organic components, we prepared a new POM-based inorganic–organic hybrid, H[Zn(Hapca)3][PW12O40]·7H2O 1 (Hapca = 3-aminopyrazine-2-carboxylic acid), composed of Keggin-type PW12O403− anions and Zn(Hapca)32+ cations. Compound 1 exhibits a proton conductivity of 1.16 × 10−4 S·cm−1 at 55 °C, which remains stable at a relative humidity of 95%. To construct POM-based conductive materials with good mechanical property, we introduced 1 into a poly(vinyl alcohol) (PVA)/glycerol (Gly) hydrogel and obtained the hydrogel composites 1@PVA/Gly-x (x = 20%, 30%, and 40%, where x is the percentage of the mass of 1 to the total mass of 1 and PVA). Remarkably, the hydrogel composites 1@PVA/Gly-x combine the merits of their components. The proton conductivity of 1@PVA/Gly-40% reaches 1.11 × 10−2 S·cm−1 at ambient humidity and 75 °C, outperforming most POM-based composite materials reported to date. Moreover, 1@PVA/Gly-40% displays good elasticity and toughness and high strain sensitivity. Additionally, we assembled 1@PVA/Gly-40% into a strain sensor for the effective monitoring of various human activities. This work provides a new platform for the transformation of crystalline POM-based inorganic–organic hybrids into materials with good mechanical properties.

Keywords: hydrogel, proton conduction, polyoxometalates, inorganic–organic hybrid

References(42)

[1]

Kim, J.; Sengodan, S.; Kim, S.; Kwon, O.; Bu, Y.; Kim, G. Proton conducting oxides: A review of materials and applications for renewable energy conversion and storage. Renew. Sust. Energy Rev. 2019, 109, 606–618.

[2]

Lei, L. B.; Zhang, J. H.; Guan, R. F.; Liu, J. P.; Chen, F. L.; Tao, Z. T. Energy storage and hydrogen production by proton conducting solid oxide electrolysis cells with a novel heterogeneous design. Energy Convers. Manage. 2020, 218, 113044.

[3]

Duan, C. C.; Huang, J.; Sullivan, N.; O'Hayre, R. Proton-conducting oxides for energy conversion and storage. Appl. Phys. Rev. 2020, 7, 011314.

[4]

Zhou, S. Y.; Guan, J. Y.; Li, Z. Q.; Huang, L.; Zheng, J. F.; Li, S. H.; Zhang, S. B. Alkaline polymers of intrinsic microporosity: High-conduction and low-loss anhydrous proton exchange membranes for energy conversion. J. Mater. Chem. A 2021, 9, 3925–3930.

[5]

Jiang, G. P.; Goledzinowski, M.; Comeau, F. J. E.; Zarrin, H.; Lui, G.; Lenos, J.; Veileux, A.; Liu, G. H.; Zhang, J.; Hemmati, S. et al. Free-standing functionalized graphene oxide solid Electrolytes in electrochemical gas sensors. Adv. Funct. Mater. 2016, 26, 1729–1736.

[6]

Kalyakin, A. S.; Medvedev, D. A.; Volkov, A. N. Electrochemical sensors based on proton-conducting electrolytes for determination of concentration and diffusion coefficient of CO2 in inert gases. Chem. Eng. Sci. 2021, 229, 116046.

[7]

Chen, Y.; Guo, Z. W.; Chen, Y. P.; Zhuang, Z. Y.; Wang, G. Q.; Li, X. X.; Zheng, S. T.; Yang, G. Y. Two novel nickel cluster substituted polyoxometalates: Syntheses, structures and their photocatalytic activities, magnetic behaviors, and proton conduction properties. Inorg. Chem. Front. 2021, 8, 1303–1311.

[8]

Liu, J. C.; Han, Q.; Chen, L. J.; Zhao, J. W.; Streb, C.; Song, Y. F. Aggregation of giant cerium-bismuth tungstate clusters into a 3D porous framework with high proton conductivity. Angew. Chem., Int. Ed. 2018, 57, 8416–8420.

[9]

Wang, S. Y.; Tong, H.; Li, H. N.; Shi, X.; Liu, D.; Li, J. H.; Guo, K. X.; Zhao, L.; Song, S. J.; Chen, L. D. et al. Synthesis of a phosphomolybdic acid/nanocrystalline titanium silicalite-1 catalyst in the presence of hydrogen peroxide for effective adsorption-oxidative desulfurization. New J. Chem. 2022, 46, 2559–2568.

[10]

Osamu, N.; Teruo, K.; Isao, O.; Yoshizo, M. High-conductivity solid proton conductors: Dodecamolybdophosphoric acid and dodecatungstophosphoric acid crystals. Chem. Lett. 1979, 8, 17–18.

[11]

Wei, M. L.; Zhuang, P. F.; Li, H. H.; Yang, Y. H. Crystal structures and conductivities of two organic-inorganic hybrid complexes based on poly-keggin-anion chains. Eur. J. Inorg. Chem. 2011, 2011, 1473–1478.

[12]

Yin, P. C.; Bayaguud, A.; Cheng, P.; Haso, F.; Hu, L.; Wang, J.;Vezenov, D.; Winans, R. E.; Hao, J.; Li, T. et al. Spontaneous stepwise self-assembly of a polyoxometalate-organic hybrid into catalytically active one-dimensional anisotropic structures. Chem.—Eur. J. 2014, 20, 9589–9595.

[13]

Ogiwara, N.; Iwano, T.; Ito, T.; Uchida, S. Proton conduction in ionic crystals based on polyoxometalates. Coord. Chem. Rev. 2022, 462, 214524.

[14]

Zhang, J. W.; Huang, Y. C.; Li, G.; Wei, Y. G. Recent advances in alkoxylation chemistry of polyoxometalates: From synthetic strategies, structural overviews to functional applications. Coord. Chem. Rev. 2019, 378, 395–414.

[15]

Hu, S. M.; Li, K. Q.; Yu, X. J.; Jin, Z. X.; Xiao, B. X.; Yang, R. R.; Pang, H. J.; Ma, H. Y.; Wang, X. M.; Tan, L. C. et al. Enhancing the electrochemical capacitor performance of Keggin polyoxometalates by anchoring cobalt-triazole complexes. J. Mol. Struct. 2022, 1250, 131753.

[16]

Wang, X.; Lin, J. F.; Li, H.; Wang, C. Y.; Wang, X. L. Carbazole-based bis-imidazole ligand-involved synthesis of inorganic-organic hybrid polyoxometalates as electrochemical sensors for detecting bromate and efficient catalysts for selective oxidation of thioether. RSC Adv. 2022, 12, 4437–4445.

[17]

Cao, X. L.; Xie, S. L.; Li, S. L.; Dong, L. Z.; Liu, J.; Liu, X. X.; Wang, W. B.; Su, Z. M.; Guan, W.; Lan, Y. Q. A well-established POM-based single-crystal proton-conducting model incorporating multiple weak interactions. Chem.—Eur. J. 2018, 24, 2365–2369.

[18]

Yang, H.; Duan, X. Y.; Lai, J. J.; Wei, M. L. Proton-conductive Keggin-type clusters decorated by the complex moieties of Cu(II) 2,2'-bipyridine-4,4'-dicarboxylate/diethyl analogues. Inorg. Chem. 2019, 58, 1020–1029.

[19]

Chakraborty, P.; Das, S.; Nandi, A. K. Conducting gels: A chronicle of technological advances. Prog. Polym. Sci. 2019, 88, 189–219.

[20]

Liu, J.; Huang, J. W.; Cai, Q. P.; Yang, Y. X.; Luo, W. A.; Zeng, B. R.; Xu, Y. T.; Yuan, C. H.; Dai, L. Z. Design of slidable polymer networks: A rational strategy to stretchable, rapid self-healing hydrogel electrolytes for flexible supercapacitors. ACS Appl. Mater. Interfaces 2020, 12, 20479–20489.

[21]

Wang, L. R.; Xu, T. L.; Zhang, X. J. Multifunctional conductive hydrogel-based flexible wearable sensors. TrAC Trends Anal. Chem. 2021, 134, 116130.

[22]

Wang, Q. H.; Guo, J. J.; Lu, X. M.; Ma, X. J.; Cao, S. L.; Pan, X. F.; Ni, Y. B. Wearable lignin-based hydrogel electronics: A mini-review. Int. J. Biol. Macromol. 2021, 181, 45–50.

[23]

Ying, B. B.; Liu, X. Y. Skin-like hydrogel devices for wearable sensing, soft robotics and beyond. iScience 2021, 24, 103174.

[24]

Bae, J.; Park, J.; Kim, S.; Cho, H.; Kim, H. J.; Park, S.; Shin, D. S. Tailored hydrogels for biosensor applications. J. Ind. Eng. Chem. 2020, 89, 1–12.

[25]

Chan, D.; Chien, J. C.; Axpe, E.; Blankemeier, L.; Baker, S. W.; Swaminathan, S.; Piunova, V. A.; Zubarev, D. Y.; Maikawa, C. L.; Grosskopf, A. K. et al. Combinatorial polyacrylamide hydrogels for preventing biofouling on implantable biosensors. Adv. Mater. 2022, 34, 2109764.

[26]

Yang, G. G.; Zhu, K. H.; Guo, W.; Wu, D. R.; Quan, X. L.; Huang, X.; Liu, S. Y.; Li, Y. Y.; Fang, H.; Qiu, Y. Q. et al. Adhesive and hydrophobic bilayer hydrogel enabled on-skin biosensors for high-fidelity classification of human emotion. Adv. Funct. Mater. 2022, 32, 2200457.

[27]

Wan, X. J.; Xie, Q. R.; Song, H. Q.; Li, C. M.; Wang, J. W. Borax-crosslinked hydrogel electrolyte membranes for quasi-solid state aqueous energy storage devices. J. Membr. Sci. 2022, 655, 120606.

[28]

Wang, C. J.; Zhai, S. L.; Yuan, Z. W.; Chen, J. S.; Yu, Z. X.; Pei, Z. X.; Liu, F.; Li, X. Z.; Wei, L.; Chen, Y. Drying graphene hydrogel fibers for capacitive energy storage. Carbon 2020, 164, 100–110.

[29]

Zhang, W.; Feng, P.; Chen, J.; Sun, Z. M.; Zhao, B. X. Electrically conductive hydrogels for flexible energy storage systems. Prog. Polym. Sci. 2019, 88, 220–240.

[30]

Li, B.; Xuan, L. Y.; Wu, L. X. Polyoxometalate-containing supramolecular gels. Macromol. Rapid Commun. 2022, 43, 2200019.

[31]

Gao, H.; Lian, K. A H5BW12O40-polyvinyl alcohol polymer electrolyte and its application in solid supercapacitors. J. Mater. Chem. A 2016, 4, 9585–9592.

[32]

Guo, H. K.; Zeng, M. H.; Li, X.; He, H. B.; Wu, L. X.; Li, H. L. Multifunctional enhancement of proton-conductive, stretchable, and adhesive performance in hybrid polymer electrolytes by polyoxometalate nanoclusters. ACS Appl. Mater. Interfaces 2021, 13, 30039–30050.

[33]

Cheng, D. M.; Li, B.; Sun, S.; Zhu, L. J.; Li, Y.; Wu, X. L.; Zang, H. Y. Proton-conducting polyoxometalates as redox electrolytes synergistically boosting the performance of self-healing solid-state supercapacitors with polyaniline. CCS Chem. 2021, 3, 1649–1658.

[34]

Wei, X. R.; Ma, K.; Cheng, Y. B.; Sun, L. Y.; Chen, D. J.; Zhao, X. L.; Lu, H.; Song, B. T.; Yang, K. W.; Jia, P. X. Adhesive, conductive, self-healing, and antibacterial hydrogel based on chitosan-polyoxometalate complexes for wearable strain sensor. ACS Appl. Polym. Mater. 2020, 2, 2541–2549.

[35]

Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A. K.; Puschmann, H. OLEX2:A complete structure solution, refinement and analysis program. J. Appl. Crystallogr. 2009, 42, 339–341.

[36]

Sheldrick, G. M. SHELXT - Integrated space-group and crystal-structure determination. Acta Crystallogr. Sect. A 2015, 71, 3–8.

[37]

Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Crystallogr. Sect. C-Struct. Chem. 2015, 71, 3–8.

[38]

Ji, N. N.; Shi, Z. Q.; Xie, X. X.; Li, G. Polyoxometalate-based hydrogen-bonded organic frameworks as a new class of proton conducting materials. CrystEngComm 2020, 22, 8161–8165.

[39]

Wei, M. L.; Wang, X. X.; Sun, J. J.; Duan, X. Y. A 3D POM-MOF composite based on Ni(ΙΙ) ion and 2,2′-bipyridyl-3,3′-dicarboxylic acid: Crystal structure and proton conductivity. J. Solid State Chem. 2013, 202, 200–206.

[40]

Qi, X.; Wu, W. W.; Qin, L.; Zhang, R. X.; Zhu, X.; Zhang, X. R.; Lun, H. J.; Li, Y. M. Three Keggin POMs-based coordination polymers constructed by linear N-heterocyclic ligand for proton conduction, photocatalytic activity and magnetic property. J. Solid State Chem. 2022, 312, 123167.

[41]

Zheng, Z.; Zhou, Q. J.; Li, M.; Yin, P. C. Poly(ethylene glycol) nanocomposites of sub-nanometer metal oxide clusters for dynamic semi-solid proton conductive electrolytes. Chem. Sci. 2019, 10, 7333–7339.

[42]

He, H. B.; Wang, G.; Chai, S. C.; Li, X.; Zhai, L.; Wu, L. X.; Li, H. L. Self-assembled lamellar nanochannels in polyoxometalate-polymer nanocomposites for proton conduction. Chin. Chem. Lett. 2021, 32, 2013–2016.

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Received: 07 July 2022
Revised: 12 August 2022
Accepted: 25 August 2022
Published: 15 September 2022
Issue date: September 2022

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© The Author(s) 2022. Polyoxometalates published by Tsinghua University Press.

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