In‐Situ Formed Electron Inhibitor Enabling Dendrite‐free Garnet Electrolytes: A Case Study of Fumed Silica

Abstract Ta‐doped Li 7 La 3 Zr 2 O 12 (LLZTO) solid‐state electrolytes (SEs) show great promise for solid‐state batteries due to its high conductivity and safety. However, one of the challenges it faces is lithium dendrite propagation upon long‐term cycling. To address this issue, we propose the incorporation of fumed silica (FS) at the grain boundaries of LLZTO to modify the properties of the garnet pellet, which effectively inhibits the dendrite growth. The introduction of FS has demonstrated several beneficial effects. Firstly, it reduces the migration barrier of lithium ions, which helps prevent dendrite formation and propagation. Additionally, FS reduces the electronic conductivity of the SEs pellet, suppressing the dendrite formation. Moreover, the formed lithium silicates from FS might also be acted as electron inhibitor, thus inhibiting the lithium dendrite growth upon cycling. By investigating the use of FS as a modifier in LLZTO‐based electrolytes, our study contributes to advancing dendrite‐free solid‐state electrolytes and thus the development of high‐performance all‐solid‐state batteries.