A Self-Growing 3D Porous Sn Protective Layer Enhanced Zn Anode

Abstract

Aqueous zinc-ion batteries (ZIBs) have received much attention because of their high safety, low pollution, and satisfactory energy density (840 mAh g−1), which is important for the research of new energy storage devices. However, problems such as short cell cycle life and low coulombic efficiency (CE) of zinc (Zn) anodes due to disorderly growth of Zn dendrites and side reactions of hydrogen corrosion have delayed the practical application of ZIBs. In this work, a new “self-growth” method is proposed to build a robust and homogeneous three-dimensional (3D) nanoporous structure of tin (Sn)-coated Zn anodes (ZSN) in just 10 min by a simple and fast reaction, which can largely raise the surface area of the electrode plate. The ZSN not only provides abundant Zn nucleation sites, but also reduces the corrosion current, thus alleviating the self-corrosion of the electrolyte, reducing the occurrence of hydrogen precipitation side reactions, and effectively inhibiting the growth of Zn dendrites during cycling. Thus, a symmetric cell with a ZSN anode can be stabilized with very low voltage hysteresis (30 mV) for 480 h of stable plating/stripping cycles and can operate well for 200 h even at high current densities of 10 mA cm−2. Supercapacitors and button cells were assembled, respectively, to verify the performance of ZSN electrodes in different energy storage tools. The ZSN||AC supercapacitor exhibited superior capacity (75 mAh g−1) and high reversibility (98% coulombic efficiency) at a current density of 2 A g−1. With a MnVO (MVO) electrode as the cathode, the ZSN||MVO full cell presents excellent cycling stability with a capacity retention of 95.4% after 500 cycles at 2 A g−1, which far exceeds that of the bare Zn cell.