Interface engineering in solid state Li metal batteries by quasi-2D hybrid perovskites

Solid-state lithium batteries (SSLBs) composed of garnet-type solid electrolytes have been intensively investigated with rapid progress, but the battery capacity does not meet the commercialization requirements yet. Metal-halide perovskites (MHP), including three-dimensional perovskite (3D-PVSK) and two-dimensional perovskite (2D-PVSK), have recently emerged as superior semiconductors widely used in optoelectronics. As an ionic conductor, the MHP shows promising potential application in SSLBs, which is rarely explored. Herein, 3D-PVSK and 2D-PVSK are utilized to modify the garnet solid electrolyte (Li_6.75La₃Zr_1.75Ta_0.25O₁₂, LLZTO) through the solution process. Coupling with the LiFePO₄ cathode, the resultant SSLBs exhibit improved specific capacity of 153 mA h g⁻¹ and 149 mA h g⁻¹ for 3D-PVSK and 2D-PVSK cells after 50 cycling at 0.2C, respectively. It thus unambiguously illustrates the enhancement of lithium storage of SSLBs with MHP modification, which suggests an alternative path to increase the battery capacity for the development of SSLBs.