Yang Gongzheng, Wei Tongye, Wang Chengxin
ACS Appl Mater Interfaces. 2018 Oct 17;10(41):35079-35089. doi: 10.1021/acsami.8b10849. Epub 2018 Oct 8.
Rechargeable aqueous zinc-ion batteries have been considered one of the promising alternative energy-storage systems to lithium ion-batteries owing to their low cost and high safety. However, there is lack of long-life positive materials, which severely restricts the development of zinc-ion batteries. The strong interactions present between the intercalated multivalent cations and host materials inevitably cause structural distortions and create large migration barriers for the diffusion of cations, resulting in poor cycling stability and limited rate performance. Here, we report the application of bilayered ammonium vanadium oxide (NHVO) as the cathode material for zinc-ion batteries. A self-healing lamellar structure, which combines a macroscopically reversible morphological transformation and a microscopically adjustable interlayer spacing to accommodate the strong interactions, is observed upon insertion and release of cations. This stable architecture enables a specific capacity of 147 mA h g at a current density of 200 mA g (voltage window: 1.7-0.8 V vs Zn/Zn) and a capacity retention of more than 70.3% over 5000 cycles (5000 mA g). Our finding provides a new alternative for zinc-ion batteries and inspiration for how to further develop advanced positive electrodes by employing materials with flexible microarchitectures.
由于成本低和安全性高，可充电水系锌离子电池被认为是锂离子电池有前景的替代储能系统之一。然而，缺乏长寿命的正极材料严重限制了锌离子电池的发展。嵌入的多价阳离子与主体材料之间存在的强相互作用不可避免地会导致结构畸变，并为阳离子扩散产生较大的迁移障碍，从而导致循环稳定性差和倍率性能受限。在此，我们报道了双层铵钒氧化物（NHVO）作为锌离子电池正极材料的应用。在阳离子嵌入和脱嵌时，观察到一种自修复层状结构，它结合了宏观上可逆的形态转变和微观上可调节的层间距以适应强相互作用。这种稳定的结构在200 mA g的电流密度下（电压窗口：相对于Zn/Zn为1.7 - 0.8 V）可实现147 mA h g的比容量，并且在5000次循环（5000 mA g）中容量保持率超过70.3%。我们的发现为锌离子电池提供了一种新的选择，并为如何通过使用具有灵活微结构的材料进一步开发先进正极提供了灵感。
