A Static Tin–Manganese Battery with 30000-Cycle Lifespan Based on Stabilized Mn<sup>3+</sup>/Mn<sup>2+</sup> Redox Chemistry
Xuejin Li, Yongchao Tang, Cuiping Han, Zhiquan Wei, Haodong Fan, Haiming Lv, Tonghui Cai, Yongpeng Cui, Wei Xing, Zifeng Yan, Chunyi Zhi, Hongfei Li
Abstract
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.