Synergistic Regulation of Hierarchical Anode Interphase and Cathode Electronic Structure by a Fe(III) Complex for High-Performance Aqueous Zinc-Manganese Battery

Aqueous zinc-ion batteries (AZIBs), particularly zinc-manganese (Zn-Mn) systems, hold great promise for large-scale energy storage but face challenges from parasitic reactions of the anode and poor conductivity of the cathode. Herein, a multifunctional additive naphthol green B (NGB), which contains a planar organic group and a transition metal ion, is applied to concurrently address anode and cathode issues during battery cycling. Specifically, the adsorption and partial decomposition of the planar organic group construct a hierarchical interfacial layer on the anode surface, comprising an organic outer phase and an inorganic inner phase, assists to alleviate side reactions and modulate zinc deposition. Meanwhile, Fe 3+ ions released from NGB incorporate into the α-MnO 2 cathode during discharge, increasing oxygen defects and lowering the Mn average oxidation state, which improves the structural stability and electrical conductivity of the Mn-based cathode, further boosting capacity and cycling performance. Consequently, the Zn‖Zn cell demonstrates stable operation for 3500 h at 1 mA cm −2 , and the Zn‖Cu cell achieves an average Coulombic efficiency of 99.87% over 2500 cycles at 5 mA cm −2 . Notably, the Zn‖MnO 2 cell employing modified electrolyte exhibits no capacity decay after cycling 250 and 1000 times at 0.2 and 1 A g −1 , respectively. This work presents new perspectives on simultaneously addressing anode and cathode issues in AZIBs based on electrolyte engineering, highlighting the function of the additive structure and composition.