Tuesday, 11 October 2022: 16:40
Galleria 4 (The Hilton Atlanta)
Aqueous zinc metal batteries (AZMBs) are safe, environmentally friendly, and cost-effective, and are considered as a replacement for lithium-ion batteries in large-scale energy storage. However, the decomposition of water molecules leads to severe side reactions, resulting in the limited lifespan of Zn batteries. Although plenty of efforts has been devoted to reducing the water activity and modulating the solvation structure around Zn2+ by electrolyte design, those electrolytes usually sacrifice some properties such as stability, viscosity, ionic conductivity, etc. Here, the tetrahydrofuran (THF) additive was introduced into the zinc sulfate (ZnSO4) electrolyte to reduce the water activity by modulating the solvation structure of the Zn hydration layer. The tetrahydrofuran molecule can play as a proton acceptor to form hydrogen bonds with water molecules. The DFT calculation shows that the solvation energy is reduced by the THF additive. Thus, in an optimal 2M ZnSO4/THF (5% by volume) electrolyte, the generation of hydrogen and by-products can be suppressed, which greatly improves the cycling stability and Coulombic efficiency of reversible Zn plating/stripping. the Zn symmetrical cell with the 2M ZnSO4/THF 5% electrolyte achieved an ultralong cycling life of 1300 h at 0.5 mA cm-2 and 0.5 mAh cm-2 with the 10-fold improvement compared to baseline 2M ZnSO4 electrolyte. 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 Zn||MnO2 full cells. This work offers an effective strategy with high scalability and low cost for the protection of Zn metals electrodes in aqueous recharge batteries. The new approach will inspire the academic researcher further to find and work on such low-cost and facile materials/techniques that can help in the practical realization and applications of next-generation batteries.