Boosting lithium ion conductivity of antiperovskite solid electrolyte by potassium ions substitution for cation clusters
Lei Gao, Xinyu Zhang, Jinlong Zhu, Songbai Han, Hao Zhang, Liping Wang, Ruo Zhao, Song Gao, Shuai Li, Yonggang Wang, Dubin Huang, Yusheng Zhao, Ruqiang Zou
Abstract
Abstract Solid-state electrolytes with high ionic conductivities are crucial for the development of all-solid-state lithium batteries, and there is a strong correlation between the ionic conductivities and underlying lattice structures of solid-state electrolytes. Here, we report a lattice manipulation method of replacing [Li 2 OH] + clusters with potassium ions in antiperovskite solid-state electrolyte (Li 2 OH) 0.99 K 0.01 Cl, which leads to a remarkable increase in ionic conductivity (4.5 × 10 ‒3 mS cm ‒1 , 25 °C). Mechanistic analysis indicates that the lattice manipulation method leads to the stabilization of the cubic phase and lattice contraction for the antiperovskite, and causes significant changes in Li-ion transport trajectories and migration barriers. Also, the Li||LiFePO 4 all-solid-state battery (excess Li and loading of 1.78 mg cm ‒2 for LiFePO 4 ) employing (Li 2 OH) 0.99 K 0.01 Cl electrolyte delivers a specific capacity of 116.4 mAh g ‒1 at the 150th cycle with a capacity retention of 96.1% at 80 mA g ‒1 and 120 °C, which indicates potential application prospects of antiperovskite electrolyte in all-solid-state lithium batteries.