Dong Shengyang, Wang Yi, Chen Chenglong, Shen Laifa, Zhang Xiaogang
School of Chemistry and Materials Science, Institute of Advanced Materials and Flexible Electronics (IAMFE), Nanjing University of Information Science and Technology, Nanjing, 210044, People's Republic of China.
Jiangsu Key Laboratory of Electrochemical Energy Storage Technologies, College of Materials Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, People's Republic of China.
Nanomicro Lett. 2020 Aug 18;12(1):168. doi: 10.1007/s40820-020-00508-z.
Aqueous hybrid supercapacitors are attracting increasing attention due to their potential low cost, high safety and eco-friendliness. However, the narrow operating potential window of aqueous electrolyte and the lack of suitable negative electrode materials seriously hinder its future applications. Here, we explore high concentrated lithium acetate with high ionic conductivity of 65.5 mS cm as a green "water-in-salt" electrolyte, providing wide voltage window up to 2.8 V. It facilitates the reversible function of niobium tungsten oxide, NbWO, that otherwise only operations in organic electrolytes previously. The NbWO with lithium-ion intercalation pseudocapacitive behavior exhibits excellent rate performance, high areal capacity, and ultra-long cycling stability. An aqueous lithium-ion hybrid capacitor is developed by using NbWO as negative electrode combined with graphene as positive electrode in lithium acetate-based "water-in-salt" electrolyte, delivering a high energy density of 41.9 W kg, high power density of 20,000 W kg and unexceptionable stability of 50,000 cycles.
水系混合超级电容器因其潜在的低成本、高安全性和环境友好性而受到越来越多的关注。然而，水系电解质狭窄的工作电位窗口以及缺乏合适的负极材料严重阻碍了其未来的应用。在此，我们探索了具有65.5 mS cm高离子电导率的高浓度醋酸锂作为一种绿色的“盐包水”电解质，可提供高达2.8 V的宽电压窗口。这促进了铌钨氧化物NbWO的可逆功能，否则它以前只能在有机电解质中运行。具有锂离子嵌入赝电容行为的NbWO表现出优异的倍率性能、高面积容量和超长的循环稳定性。通过在基于醋酸锂的“盐包水”电解质中使用NbWO作为负极并与石墨烯作为正极相结合，开发了一种水系锂离子混合电容器，其具有41.9 W kg的高能量密度、20,000 W kg的高功率密度和50,000次循环的出色稳定性。
