Highly Stable Plating/Stripping Behavior of Zinc Metal Anodes in Aqueous Zinc Batteries Regulated by Quaternary Ammonium Cationic Salts

Graphical Last a lifetime : Quaternary ammonium cationic compounds are developed as electrolyte-regulating agents to guide homogeneous zinc plating, thereby effectively suppressing the formation of zinc dendrites. In the electrolyte containing proper regulating agent, highly reversible Zn stripping/plating performance with an ultra-long cycling time of 3000 h and a high average coulombic efficiency of 99.7 % are achieved. Aqueous zinc-ion batteries (AZIBs) have attracted wide attention as large-scale energy storage systems, owing to their obvious merits such as high safety, low cost, and simple maintenance. However, the development of AZIBs is seriously hindered by Zn dendrite-induced low efficiency, cell fading, and even cell short-circuiting. Unlike the traditional anode modification strategies, this work stabilized the Zn anode by functionalizing the aqueous electrolyte with a series of quaternary ammonium cationic compounds. The cations of the compounds can be adsorbed on the surface of the metallic Zn during electrodeposition process, which alters the nucleation and deposition behavior of zinc ions according to the molecular structure of the cations. Tetraethyl ammonium bromide (TEAB) was, for the first time, demonstrated to guide homogeneous Zn deposition, thereby inhibiting the growth of dendrites in near-neutral electrolytes. Highly reversible Zn stripping/plating performance with an average coulombic efficiency of 99.7 % is achieved. Particularly, the Zn−Zn symmetric cell based on TEAB-containing electrolyte exhibits an ultra-long cycling time of 3000 h at 1 mA cm −2 and even 800 h at 5 mA cm −2 ; the Zn−MnO 2 full cell shows stable cycling under the condition of the practical-level mass loading.