Decreasing Water Activity Using the Tetrahydrofuran Electrolyte Additive for Highly Reversible Aqueous Zinc Metal Batteries
Decreasing Water Activity Using the Tetrahydrofuran Electrolyte Additive for Highly Reversible Aqueous Zinc Metal Batteries
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DOI：
10.1021/acsami.2c17714
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发表时间：
2023-01-25
影响因子：
9.5
通讯作者：
Zhou, Yue
中科院分区：
文献类型：
--
作者：
He, Wei;Ren, Yao;Zhou, Yue
水锌金属电池在大规模储能方面显示出巨大的前景。然而，水分子的分解会导致严重的副反应，导致锌电池的寿命有限。本文将四氢呋喃（THF）添加剂引入硫酸锌（ZnSO4）电解质中，通过调节锌水化层的溶剂化结构来降低水活度。THF分子可以作为质子受体与水分子形成氢键，从而防止由水引起的不良反应。因此，在最佳的2 M ZnSO4/THF（体积比5%）电解液中，可以抑制析氢反应和副产物沉淀，从而大大提高了可逆镀/汽提锌的循环稳定性和库仑效率。锌对称电池具有超长的工作周期和宽范围的电流密度和容量。THF添加剂在Zn||Cu电池中具有很高的库仑效率，400次循环平均为99.59%，在Zn与MnO2平行的电池中250次循环后具有很高的可逆容量，容量保持率为97.56%。本研究为保护锌金属电极提供了一种高可扩展性和低成本的有效策略。
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 (ZnSO4) 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 ZnSO4/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 parallel to MnO2 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.