Tin (Sn) is an appealing metal anode for aqueous batteries (ABs) due to its high theoretical capacity, elevated hydrogen overpotential, affordability and environmentally friendly nature. However, the parasitic reaction and dead Sn formation are two critical issues that impede the practical application of Sn metal batteries. Herein, we demonstrate that the addition of trace amount of polyvinylpyrrolidone (PVP, 1 mM) into the pristine electrolyte can effectively solve these issues. Specifically, the PVP additive can reshape the structure of Sn2+ solvation sheath to accelerate cations migration and suppress water-induced side reaction and the formation of hydroxide sulfate. Additionally, the preferential adsorption of PVP at the interface also promotes the three-dimensional (3D) diffusion of Sn2+, facilitating uniform Sn deposition. As a result, symmetric cells with PVP additive in the electrolyte deliver stable cycling for up to 1800 h at 10 mA cm−2/1 mAh cm−2 or 230 h at 5 mA cm−2/10 mAh cm−2. The designed electrolyte also enables the MnO2//Sn full battery to maintain a discharge capacity of 0.92 mAh cm−2 over 3000 cycles at current density of 6 mA cm−2 and supports the stable cycling of PbO2//Sn full battery for 230 cycles under the high capacity of 10 mAh cm−2.

中文翻译：

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通过调整电解质溶剂化化学和界面吸附分子层实现高面容量和长寿命 Sn 阳极


锡 （Sn） 是一种有吸引力的水系电池 （AB） 金属负极，因为它具有高理论容量、高氢过电位、经济性和环保性。然而，寄生反应和死 Sn 的形成是阻碍 Sn 金属电池实际应用的两个关键问题。在此，我们证明在原始电解质中添加痕量的聚乙烯吡咯烷酮 （PVP， 1 mM） 可以有效解决这些问题。具体来说，PVP 添加剂可以重塑 Sn2+ 溶剂化鞘的结构，以加速阳离子迁移并抑制水诱导的副反应和氢氧化物硫酸盐的形成。此外，PVP 在界面处的优先吸附也促进了 Sn2+ 的三维 （3D） 扩散，促进了均匀的 Sn 沉积。因此，在电解质中添加了 PVP 添加剂的对称电池可在 10 mA cm-2/1 mAh cm-2 下提供长达 1800 小时的稳定循环，或在 5 mA cm-2/10 mAh cm-2 下提供长达 230 小时的稳定循环。设计的电解液还使 MnO2//Sn 满电池能够在 6 mA cm-2 的电流密度下在 3000 次循环中保持 0.92 mAh cm-2 的放电容量，并支持 PbO2//Sn 满电池在 10 mAh cm-2 的高容量下稳定循环 230 次循环。