Wan Fang, Zhang Yan, Zhang Linlin, Liu Daobin, Wang Changda, Song Li, Niu Zhiqiang, Chen Jun
Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
National Synchrotron Radiation Laboratory, School of Chemistry and Materials Science, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, 230026, P. R. China.
Angew Chem Int Ed Engl. 2019 May 20;58(21):7062-7067. doi: 10.1002/anie.201902679. Epub 2019 Apr 17.
Rechargeable aqueous zinc-ion batteries (ZIBs) are promising energy-storage devices owing to their low cost and high safety. However, their energy-storage mechanisms are complex and not well established. Recent energy-storage mechanisms of ZIBs usually depend on cationic redox processes. Anionic redox processes have not been observed owing to the limitations of cathodes and electrolytes. Herein, we describe highly reversible aqueous ZIBs based on layered VOPO cathodes and a water-in-salt electrolyte. Such batteries display reversible oxygen redox chemistry in a high-voltage region. The oxygen redox process not only provides about 27 % additional capacity, but also increases the average operating voltage to around 1.56 V, thus increasing the energy density by approximately 36 %. Furthermore, the oxygen redox process promotes the reversible crystal-structure evolution of VOPO during charge/discharge processes, thus resulting in enhanced rate capability and cycling performance.
可充电水系锌离子电池（ZIBs）因其低成本和高安全性而成为很有前景的储能装置。然而，它们的储能机制复杂且尚未完全确立。近期ZIBs的储能机制通常依赖于阳离子氧化还原过程。由于阴极和电解质的限制，尚未观察到阴离子氧化还原过程。在此，我们描述了基于层状VOPO阴极和盐包水电解质的高度可逆水系ZIBs。这种电池在高压区域显示出可逆的氧氧化还原化学。氧氧化还原过程不仅提供了约27%的额外容量，还将平均工作电压提高到约1.56 V，从而使能量密度提高了约36%。此外，氧氧化还原过程促进了VOPO在充放电过程中可逆的晶体结构演变，从而提高了倍率性能和循环性能。
