Wu Cuiping, Xie Kaixuan, Ren Kaixin, Yang Shun, Wang Qinghong
School of Chemistry and Materials Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, P.R. China.
Dalton Trans. 2020 Dec 22;49(48):17629-17634. doi: 10.1039/d0dt03459b.
Rechargeable aqueous zinc-ion batteries possess the merits of good environmental benignity, high operational safety and high energy density. Nevertheless, the practical application of zinc-ion batteries is severely obstructed by the inhomogeneous deposition of metallic Zn on the anode, which results in serious capacity fading, poor coulombic efficiency, and electrolyte consumption. Herein, we propose a simple strategy of constructing a functional nitrogen-doped carbon network coating layer on zinc foil for dendrite-free Zn stripping/plating. On one hand, the good conductivity of the artificial Zn/electrolyte interface can quickly balance the electric field and lower the nucleation overpotential. On the other hand, the porosity feature and functional groups of the protective layer can provide a fast Zn2+ transportation pathway and generate well-dispersed nucleation seeds. Therefore, the protective layer can effectively hamper the growth of metallic Zn dendrites and resist side reactions. The as-prepared N-C/Zn anode displays superior cycling stability (800 h at 2 mA cm-2 with the capacity of 2 mA h cm-2) and a satisfactory coulombic efficiency of 98.76% during the Zn stripping/plating process. A long cycle life and high specific capacity (162.10 mA h g-1 after 500 cycles at 2.0 A g-1) are also obtained for N-C/Zn||ZnSO4||V2O5 full cells. The strategy provides a facile and effective opportunity for constructing high-performance rechargeable aqueous zinc-ion batteries.
可充电水系锌离子电池具有环境友好性好、运行安全性高和能量密度高的优点。然而，锌离子电池的实际应用受到金属锌在阳极上不均匀沉积的严重阻碍，这导致严重的容量衰减、较差的库仑效率和电解质消耗。在此，我们提出了一种在锌箔上构建功能性氮掺杂碳网络涂层以实现无枝晶锌剥离/电镀的简单策略。一方面，人工锌/电解质界面的良好导电性可以快速平衡电场并降低成核过电位。另一方面，保护层的孔隙特征和官能团可以提供快速的Zn2+传输途径并产生分散良好的成核位点。因此，该保护层可以有效地抑制金属锌枝晶的生长并抵抗副反应。所制备的N-C/Zn阳极在锌剥离/电镀过程中表现出优异的循环稳定性（在2 mA cm-2下800小时，容量为2 mA h cm-2）和令人满意的98.76%的库仑效率。对于N-C/Zn||ZnSO4||V2O5全电池，也获得了长循环寿命和高比容量（在2.0 A g-1下500次循环后为162.10 mA h g-1）。该策略为构建高性能可充电水系锌离子电池提供了一种简便有效的方法。
