Hance Su, Elizabeth L. Hinks, Yuxuan Chen, Sang Cheol Kim, Yuqi Li, Xiwen Chi, P. L. Zhang, Jing Wang, Il Rok Choi, Haiyan Mao, Isabella Huang, Xueer Xu, Zhouyi Chen, Jian Qin, Yi Cui
Our study introduces a novel electrolyte design strategy for aqueous zinc-ion batteries (AZIBs), leveraging high-entropy concepts specifically within the second solvation shell rather than the commonly targeted first shell. By combining multiple zinc salts to achieve controlled entropy enhancement, we demonstrated significantly improved zinc-ion transport kinetics, ionic conductivity, and suppression of the hydrogen evolution reactions (HER). Molecular dynamics simulations and spectroscopic analyses revealed that increased second-shell entropy weakened the hydrogen-bonding network, disrupting proton transfer pathways responsible for HER. Consequently, this high-entropy electrolyte substantially extended cycle life in symmetric cells and improved Coulombic efficiency in asymmetric configurations, outperforming conventional single-salt systems by up to 4-fold. In practical dual-electrode-free Zn–MnO 2 and Zn–NVO full cell setups, our electrolytes showed enhanced cycling stability, rate capability, and capacity retention. This work presents a transformative electrolyte approach, highlighting second-shell entropy manipulation as an effective avenue for advancing performance and sustainability in aqueous zinc-ion battery technology and beyond.