Preparing Two‐Dimensional Ordered Li0.33La0.557TiO3 Crystal in Interlayer Channel of Thin Laminar Inorganic Solid‐State Electrolyte towards Ultrafast Li+ Transfer

Abstract

AbstractInorganic superionic conductor holds great promise for high‐performance all‐solid‐state lithium batteries. However, the ionic conductivity of traditional inorganic solid electrolytes (ISEs) is always unsatisfactory owing to the grain boundary resistance and large thickness. Here, a 13 μm‐thick laminar framework with ≈1.3 nm interlayer channels is fabricated by self‐assembling rigid, hydrophilic vermiculite (Vr) nanosheets. Then, Li0.33La0.557TiO3 (LLTO) precursors are impregnated in interlayer channels and afterwards in situ sintered to large‐size, oriented, and defect‐free LLTO crystal. We demonstrate that the confinement effect permits ordered arrangement of LLTO crystal along the c‐axis (the fastest Li+ transfer direction), permitting the resultant 15 μm‐thick Vr‐LLTO electrolyte an ionic conductivity of 8.22×10−5 S cm−1 and conductance of 87.2 mS at 30 °C. These values are several times’ higher than that of traditional LLTO‐based electrolytes. Moreover, Vr‐LLTO electrolyte has a compressive modulus of 1.24 GPa. Excellent cycling performance is demonstrated with all‐solid‐state Li/LiFePO4 battery.