State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China.
State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi 830017, PR China.
J Colloid Interface Sci. 2023 Sep 15;646:679-686. doi: 10.1016/j.jcis.2023.05.093. Epub 2023 May 18.
Aqueous Zn-ion battery is expected to become a substitute for Li-ion battery due to its inherent safety, low cost, and environmental friendliness. Dendrite growth and side reaction problems during electroplating lead to its low Coulombic efficiency and unsatisfactory life, which greatly limits its practical application. Here, we propose a dual-salts hybrid electrolyte, which alleviates the above issues by mixing Zn(OTf) to ZnSO solution. Extensive tests and MD simulations have shown that the dual-salts hybrid electrolyte can regulate the solvation structure of Zn, facilitating uniform Zn deposition, and inhibiting side reactions and dendrite growth. Hence, the dual-salts hybrid electrolyte exhibits good reversibility in Zn//Zn batteries, which can provide a lifetime of more than 880 h at 1 mA cm and 1 mAh cm. Moreover, the average Coulombic efficiency of Zn//Cu cells in hybrid system can reach 98.2% after 520 h, much better than that of 90.7% in pure ZnSO electrolyte and 92.0% in pure Zn(OTf) electrolyte. Benefiting from the fast ion exchange rate and high ion conductivity, Zn-ion hybrid capacitor in hybrid electrolyte also displays excellent stability and capacitive performance. This effective strategy for dual-salts hybrid electrolytes provides a promising direction for designing aqueous electrolytes for Zn-ion batteries.
水系锌离子电池由于其固有安全性、低成本和环境友好性，有望成为锂离子电池的替代品。然而，电镀过程中枝晶生长和副反应问题导致其库仑效率低、循环寿命差，这极大地限制了其实际应用。在这里，我们提出了一种双盐混合电解液，通过将 Zn(OTf)混合到 ZnSO4 溶液中，缓解了上述问题。大量的测试和 MD 模拟表明，双盐混合电解液可以调节 Zn 的溶剂化结构，促进 Zn 的均匀沉积，并抑制副反应和枝晶生长。因此，双盐混合电解液在 Zn//Zn 电池中表现出良好的可逆性，在 1 mA cm 和 1 mAh cm 下可以提供超过 880 h 的寿命。此外，在混合体系中 Zn//Cu 电池的平均库仑效率在 520 h 后可达到 98.2%，明显优于纯 ZnSO4 电解液的 90.7%和纯 Zn(OTf)电解液的 92.0%。得益于快速的离子交换速率和高离子电导率，混合电解液中的锌离子混合电容器也表现出优异的稳定性和电容性能。这种双盐混合电解液的有效策略为设计水系锌离子电池电解液提供了有前景的方向。
