A bioimmune mechanism-inspired targeted elimination mechanism on the anode interface for zinc–iodine batteries

Abstract

Alkaline byproducts at the zinc anode interface continue to exacerbate subsequent side reactions, so realizing timely salvage of electrodes is equally important compared to upfront prevention strategies. Although the utilization of acid electrolytes could eliminate by-products on the Zn anode, they inevitably exacerbate the undesired hydrogen evolution reaction. Therefore, achieving elimination of by-products without exacerbating other side reactions is urgently needed. Inspired by the immune protection mechanisms in organisms, facile cysteamine hydrochloride (Cy-H) additives were incorporated into the aqueous electrolyte to stabilize the anode. Concretely, the Cy-H additives can reconstruct the electrical double layer (EDL) on the Zn anode and inhibit drastic parasitic reactions and cooperate with electric fields and acidic environments, thus achieving the desired effect of targeted elimination of alkaline by-products. Ultimately, with a long calendar lifespan of 2000 h with a Zn anode carrying by-products and outstanding performance over 8000 cycles for the Zn‖I₂ full cell, the assembled pouch battery also achieved 1000 cycles without capacity degradation. To further promote the practical applications, the inhibition mechanism of Cy-H additives on full-cell self-discharge was revealed. This work provides new insights for the use of strong acid electrolytes and the elimination of interfacial by-products in aqueous zinc–iodine batteries.