Self‐Assembled Homogeneous Heterobimetallic‐Oxide Interfaces Enable Synergistic Hydrogen Evolution Passivation for Durable Acidic Zn–Mn Batteries

Abstract

AbstractAcidic Zn–Mn batteries hold promising prospects in large‐scale energy storage owing to their higher discharge voltage and capacity. However, the challenge of developing long‐term acidic Zn–Mn batteries still remains due to Zn anode instability in acidic media arising from the inevitable proton corrosion and hydrogen evolution reaction (HER). Herein, we report self‐assembled homogeneous heterobimetallic‐oxide interfaces on the Zn anode surface via a multi‐cation (Cu2+, In3+, and Sn4+) synergistic regulation strategy to achieve >85.5% depth of discharge with over 1000 h of cycling in strongly acidic medium (pH = 0.9). The design ingeniously blends the SnCl4 hydrolysis and In3+ and Cu2+ ions replacement with Zn metal to spontaneously generate heterobimetallic In–CuZn5 and SnO2 oxide. Heterobimetallic‐oxide interfaces could synergistically inhibit proton corrosion and HER while inducing Zn‐ordered plating/stripping benefiting from the excellent acid resistance of SnO2 and the abundant nucleation sites of heterobimetallic. Crucially, the in situ hydrolysis of SnCl4 establishes a self‐regulated acidic environment without additional acidic medium. Consequently, Zn–Mn pouch battery within this acidic environment delivers a high capacity of 1.39 mAh cm−2 and retains 84.9% of initial capacity after 200 cycles at 1 mA cm−2. This direct multi‐cation synergistic modulated self‐assembly interface strategy holds significant potential for expediting the advancement of high‐safety, large‐scale energy storage technology.