He Wei, Ren Yao, Lamsal Buddhi Sagar, Pokharel Jyotshna, Zhang Kena, Kharel Parashu, Wu James J, Xian Xiaojun, Cao Ye, Zhou Yue
Department of Electrical Engineering and Computer Science, South Dakota State University, Brookings, South Dakota57007, United States.
Department of Materials Science and Engineering, University of Texas at Arlington, Arlington, Texas76019, United States.
ACS Appl Mater Interfaces. 2023 Feb 8;15(5):6647-6656. doi: 10.1021/acsami.2c17714. Epub 2023 Jan 25.
Aqueous zinc metal batteries show great promise in large-scale energy storage. However, the decomposition of water molecules leads to severe side reactions, resulting in the limited lifespan of Zn batteries. Here, the tetrahydrofuran (THF) additive was introduced into the zinc sulfate (ZnSO) electrolyte to reduce water activity by modulating the solvation structure of the Zn hydration layer. The THF molecule can play as a proton acceptor to form hydrogen bonds with water molecules, which can prevent water-induced undesired reactions. Thus, in an optimal 2 M ZnSO/THF (5% by volume) electrolyte, the hydrogen evolution reaction and byproduct precipitation can be suppressed, which greatly improves the cycling stability and Coulombic efficiency of reversible Zn plating/stripping. The Zn symmetrical cells exhibit ultralong working cycles with a wide range of current density and capacity. The THF additive also enables a high Coulombic efficiency in the Zn||Cu cell with an average value of 99.59% over 400 cycles and a high reversible capacity with a capacity retention of 97.56% after 250 cycles in the Zn||MnO full cells. This work offers an effective strategy with high scalability and low cost for the protection of the Zn metal electrodes in aqueous rechargeable batteries.
水系锌金属电池在大规模储能方面展现出巨大潜力。然而，水分子的分解会导致严重的副反应，从而限制了锌电池的使用寿命。在此，将四氢呋喃（THF）添加剂引入硫酸锌（ZnSO）电解液中，通过调节锌水合层的溶剂化结构来降低水的活性。THF分子可作为质子受体与水分子形成氢键，从而防止水引发的不良反应。因此，在最优的2 M ZnSO/THF（体积分数5%）电解液中，析氢反应和副产物沉淀能够得到抑制，这极大地提高了可逆锌电镀/剥离的循环稳定性和库仑效率。锌对称电池在宽电流密度和容量范围内展现出超长的工作循环。THF添加剂还能使Zn||Cu电池具有高库仑效率，在400次循环中平均值为99.59%，并且在Zn||MnO全电池中，经过250次循环后具有高可逆容量，容量保持率为97.56%。这项工作为水系可充电电池中锌金属电极的保护提供了一种具有高扩展性和低成本的有效策略。
