Mercapto-Functionalized Sacrificial Agents Enable Dual-Electrode Nanoprotection in MnO₂||Zn Batteries

Aqueous zinc-ion batteries (AZIBs) offer significant promise for large-scale applications due to their low cost, high safety, and sustainability, prompting researchers to address the key issues of zinc dendrite formation, anode side reactions, and cathode dissolution. Despite most current research focusing on optimizing either the anode or the cathode, achieving coordinated improvements in both electrodes is crucial for fully realizing the potential of zinc-ion batteries (ZIBs) and remains a significant challenge due to the complexity involved in balancing the performance of both electrodes. Herein, a sacrificial agent-promoted protective strategy is proposed to enhance the performance of both the anode and cathode simultaneously. Specifically, the mercapto-containing sacrificial agent adsorbs on the Zn anode, localizing electrons around the thiol group to trigger an in situ transformation reaction. This reaction forms a modulation layer that optimizes Zn²⁺ deposition. Concurrently, the agent promotes the formation of a protective MnO₂ nanoparticle shell to reduce cathode dissolution. This strategy significantly enhances the cycling stability of both the Zn||Zn and MnO₂||Zn cells, achieving 4.5 and 3 times longer performance, respectively, compared to those in ZnSO₄ electrolyte. This work presents a simple and efficient dual-function approach that simultaneously stabilizes the Zn anode and suppresses Mn-based cathode dissolution, offering a promising pathway for the practical development of AZIBs.