Reforming Multifunctional Solid Electrolyte Interphase for High-Performance Zn Anode Through a Nature-Inspired Strategy

Abstract

Aqueous Zn metal batteries (AZMBs) have appealing advantages, including good safety, low cost, and high volumetric energy density. However, serious parasitic reactions and dendrite growth at Zn anodes hinder practical applications of AZMBs. Here, a nature-inspired strategy is proposed to improve Zn anodes using plant-cell derivatives as additives for ZnSO₄ electrolytes. In the electrolyte, TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl)-oxidized cellulose nanofibers (TOCN) and calcium lignosulfonate (CL) with specific functional groups modulate the Zn²⁺ solvation structure. More importantly, they reform a cell membrane/wall-like functional layer with high mechanical strength and selective Zn²⁺ transmission/plating on the anode surface, which enables uniform Zn deposition and alleviates side reactions. As a result, symmetric cells using the dual-additive electrolyte exhibit highly reversible and dendrite-free Zn stripping/plating behavior for over 2000 and 500 h at 2 mA cm⁻²/1 mAh cm⁻² and 10 mA cm⁻²/10 mAh cm⁻², respectively. Furthermore, a Zn//NH₄V₄O₁₀ full cell using the electrolyte shows a good cycling stability over 300 cycles with a low negative/positive (N/P) ratio. A high energy density of 92.9 Wh kg⁻¹ can be delivered with limited metallic Zn consumption, showing that the electrolyte has good prospects for practical use.