Liu Xizheng, Lei Xiaofeng, Wang Yong-Gang, Ding Yi
Tianjin Key Laboratory of Advanced Functional Porous Materials, Institute for New Energy Materials and Low-Carbon Technologies, School of Materials Science and Engineering, Tianjin University of Technology, Binshui Xi dao 391, Xiqing District, 300384 Tianjin, China.
Department of Chemistry and Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Institute of New Energy, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, 200433 Shanghai, China.
ACS Cent Sci. 2021 Feb 24;7(2):335-344. doi: 10.1021/acscentsci.0c01560. Epub 2021 Jan 18.
Rechargeable Na-air batteries (NABs) based on abundant Na resources are generating great interest due to their high energy density and low cost. However, Na anode corrosion in ambient air and the growth of abnormal dendrites lead to insufficient cycle performance and safety hazards. Effectively protecting the Na anode from corrosion and inducing the uniform Na plating and stripping are therefore of vital importance for practical application. We herein report a NAB with in situ formed gel electrolyte and Na anode with trace residual Li. The gel electrolyte is obtained within cells through cross-linking Li ethylenediamine at the anode surface with tetraethylene glycol dimethyl ether (G4) from the liquid electrolyte. The gel can effectively prevent HO and O crossover, thus delaying Na anode corrosion and electrolyte decomposition. Na dendrite growth was suppressed by the electrostatic shield effect of Li from the modified Li layer. Benefiting from these improvements, the NAB achieves a robust cycle performance over 2000 h in opened ambient air, which is superior to previous results. Gelation of the electrolyte prevents liquid leakage during battery bending, facilitating greater cell flexibility, which could lead to the development of NABs suitable for wearable electronic devices in ambient air.
基于丰富钠资源的可充电钠-空气电池（NABs）因其高能量密度和低成本而备受关注。然而，钠阳极在环境空气中的腐蚀以及异常枝晶的生长导致循环性能不足和安全隐患。因此，有效保护钠阳极免受腐蚀并诱导均匀的钠电镀和剥离对于实际应用至关重要。我们在此报告一种具有原位形成凝胶电解质和含微量残余锂的钠阳极的钠-空气电池。凝胶电解质是通过在阳极表面使乙二胺锂与来自液体电解质的四甘醇二甲醚（G4）交联在电池内部获得的。该凝胶可有效防止HO和O的交叉，从而延缓钠阳极腐蚀和电解质分解。来自改性锂层的锂的静电屏蔽效应抑制了钠枝晶的生长。受益于这些改进，该钠-空气电池在开放环境空气中实现了超过2000小时的稳健循环性能，优于先前的结果。电解质的凝胶化防止了电池弯曲过程中的液体泄漏，提高了电池的柔韧性，这可能会推动适用于环境空气中可穿戴电子设备的钠-空气电池的发展。
