A Static Tin-Manganese Battery with 30000-Cycle Lifespan Based on Stabilized Mn 3+ /Mn 2+ Redox Chemistry.

High-potential Mn 3+ /Mn 2+ redox couple (>1.3 V vs SHE) in a static battery system is rarely reported due to the shuttle and disproportionation of Mn 3+ in aqueous solutions. Herein, based on reversible stripping/plating of the Sn anode and stabilized Mn 2+ /Mn 3+ redox couple in the cathode, an aqueous Sn-Mn full battery is established in acidic electrolytes. Sn anode exhibits high deposition efficiency, low polarization, and excellent stability in acidic electrolytes. With the help of H + and a complexing agent, a reversible conversion between Mn 2+ and Mn 3+ ions takes place on the graphite surface. Pyrophosphate ligand is initially employed to form a protective layer through a complexation process with Sn 4+ on the electrode surface, effectively preventing Mn 3+ from disproportionation and hindering the uncontrollable diffusion of Mn 3+ to electrolytes. Benefiting from the rational design, the full battery delivers satisfied electrochemical performance including a large capacity (0.45 mAh cm -2 at 5 mA cm -2 ), high discharge plateau voltage (>1.6 V), excellent rate capability (58% retention from 5 to 30 mA cm -2 ), and superior cycling stability (no decay after 30 000 cycles). The battery design strategy realizes a robustly stable Mn 3+ /Mn 2+ redox reaction, which broadens research into ultrafast acidic battery systems.