Li-O₂ batteries with high energy density hold significant promise as next-generation energy storage systems. However, Li-O₂ batteries have poor cycling performance at high current densities and large capacities, primarily due to the high impedance caused by the instability of the lithium anode and the sluggish kinetics in the discharge products decomposition on the cathode. Herein, we investigated a bifunctional nitrile additive (2-methoxy benzonitrile (2-MBN)) with good chemical/electrochemical stability to improve the performances of Li-O₂ batteries. The 2-MBN could actively modify the anode by ensuring uniform Li⁺ deposition and optimizing the composition of solid electrolyte interphase (SEI). Meanwhile, it could also facilitate the decomposition of discharge products by inducing the formation of sheet-like Li₂O₂, significantly reducing the battery charge overpotential. The bifunctional effects of 2-MBN for the anode and cathode enable Li-O₂ batteries to achieve a stable lifetime of 97 cycles at a current density of 600 mA·g⁻¹ with a fixed capacity of 2000 mAh·g⁻¹, much better than that of Li-O₂ batteries without 2-MBN (28 cycles). The inclusion of 2-MBN provides an effective approach for attaining high-performance Li-O₂ batteries.

Li-O₂ batteries with extremely high specific energy density have been regarded as a kind of promising successor to current Li-ion batteries. However, the high charge overpotential for the decomposition of Li₂O₂ discharge product reduces the energy efficiency and triggers a series of side reactions that cause the Li-O₂ batteries to have a limited lifetime. Herein, Co-doped C₃N₄ (Co-C₃N₄) photocatalysts were designed by an in situ thermal evaporation method to take advantage of the photo-assisted charging technology to conquer the shortcomings of Li-O₂ batteries encountered in the charge process. Different from the commonly used photocatalysts, the Co-C₃N₄ photocatalysts perform well no matter with and without illumination, owing to the Co doping induced conductivity and electrocatalytic ability enhancement. This makes the Co-C₃N₄ reduce the charge and discharge overpotentials and improve the cycling performance of Li-O₂ batteries (from 20 to 106 cycles) without illumination. While introducing illumination, the performance can be further improved: Charge voltage reduces to 3.3 V, and the energy efficiency increases to 84.84%, indicating that the Co-C₃N₄ could behave as a suitable photocathode for Li-O₂ batteries. Besides, the low charge voltage and the continuous illumination together weaken the corrosion of the Li anode, making the long-term high-efficiency operation of Li-O₂ batteries no longer just extravagant hope.

Electrochemical CO₂ reduction reaction (CO₂RR) into value-added chemicals/fuels is crucial for realizing the sustainable carbon cycle while mitigating the energy crisis. However, it is impeded by the relatively high overpotential and low energy efficiency due to the lack of efficient electrocatalysts. Herein, we develop an isolated single-atom Ni catalyst regulated strategy to activate and stabilize the iron phthalocyanine molecule (Ni SA@FePc) toward a highly efficient CO₂RR process at low overpotential. The well-defined and homogenous catalytic centers with unique structures confer Ni SA@FePc with a significantly enhanced CO₂RR performance compared to single-atom Ni catalyst and FePc molecule and afford the atomic understanding on active sites and catalytic mechanism. As expected, Ni SA@FePc exhibits a high selectivity of more significant Faraday efficiency (≥ 95%) over a wide potential range, a high current density of ~ 252 mA·cm⁻² at low overpotential (390 mV), and excellent long-term stability for CO₂RR to CO. X-ray absorption spectroscopy measurement and theoretical calculation indicate the formation of NiN₄-O₂-FePc heterogeneous structure for Ni SA@FePc. And CO₂RR prefers to occur at the raised N centers of NiN₄-O₂-FePc heterogeneous structure for Ni SA@FePc, which enables facilitated adsorption of *COOH and desorption of CO, and thus accelerated overall reaction kinetics.

Carbon dioxide reduction (CO₂RR) has become a promising way to address the energy and environmental crisis, of which the fundamental development of the optimal electrocatalysts is the crucial part. Herein, we develop Fe and N doping porous carbon nematosphere (FeNPCN) as an excellent CO₂RR electrocatalyst in aqueous electrolyte. Featuring with the high conductivity, pore structure and abundant Fe and N doping, FeNPCN exhibits high catalytic activity with a high faradaic selectivity of CO (94%) and long-term durability. Moreover, the ratio of CO and H₂ can be changed by the applied potential for the different syngas related industry. Density functional theory (DFT) calculation results also reveal that the excellent catalytic activity is likely attributed to C and N hybrid coordination with atomic Fe.

Rechargeable lithium-oxygen (Li-O₂) batteries have received intensive research interest due to its ultrahigh energy density, while its cycle stability is still hindered by the high reactivity of the Li anode with oxygen and moisture. To alleviate the corrosion of the metallic lithium anodes for achieving a stable Li-O₂ battery, and as a proof-of-concept experiment, a distinctive hybrid electrolyte system with an organic/ceramic/organic electrolyte (OCOE) architecture is designed. Importantly, the cycle number of Li-O₂ batteries with OCOE is significantly improved compared with batteries with an organic electrolyte (OE). This might be attributed to the effective suppression of the lithium anode corrosion caused by the OE degradation and the crossover of oxygen from the cathode. We consider that our facile, low-cost, and highly effective lithium protection strategy presents a new avenue to address the daunting corrosion problem of lithium metal anodes in Li-O₂ batteries. In addition, the proposed strategy can be easily extended to other metal-O₂ battery systems, such as Na-O₂ batteries.

Efficient oxygen electrocatalysts are the key elements of numerous energy storage and conversion devices, including fuel cells and metal–air batteries. In order to realize their practical applications, highly efficient and inexpensive non-noble metal-based oxygen electrocatalysts are urgently required. Herein, we report a novel iron-chelated urea-formaldehyde resin hydrogel for the synthesis of Fe-N-C electrocatalysts. This novel hydrogel is prepared using a new instantaneous (20 s) one-step scalable strategy, which theoretically ensures the atomic-level dispersion of Fe ions in the urea-formaldehyde resin, guaranteeing the microstructural homogeneity of the electrocatalyst. Consequently, the prepared electrocatalyst exhibits higher catalytic activity and durability in the oxygen reduction (ORR) and evolution (OER) reactions than the commercial Pt/C catalyst. Furthermore, the above catalyst also shows a much better performance in rechargeable Zn–air batteries, including higher power density and better cycling stability. The developed synthetic approach opens up new avenues toward the development of sustainable active electrocatalysts for electrochemical energy devices.

Hierarchical Co₃O₄ porous nanowires (NWs) have been synthesized using a hydrothermal method followed by calcination. When employed as a cathode catalyst in non-aqueous Li-oxygen batteries, the Co₃O₄ NWs effectively improve both the round-trip efficiency and cycling stability, which can be attributed to the high catalytic activities of Co₃O₄ NWs for the oxygen reduction reaction and the oxygen evolution reaction during discharge and charge processes, respectively.