Lithium Lanthanum Titanate (LLTO) Solid Electrolyte with High Ionic Conductivity and Excellent Mechanical Properties Prepared by Aerodynamic Levitation Rapid Solidification

Abstract

Lithium lanthanum titanate (LLTO) is a promising solid electrolyte for all-solid-state lithium-ion batteries (ASSLIBs), and its total conductivity is dramatically influenced by the ceramic microstructure. Here we report a novel aerodynamic levitation rapid solidification method to prepare dense LLTO ceramics with a dendrite-like microstructure, which can be hardly obtained by conventional sintering. At optimal nominal lithium content and cooling rate, the solidified LLTO ceramic achieved a high total conductivity of 2.5 × 10−4 S·cm−1 at room temperature, along with excellent mechanical properties such as a high Young’s modulus of 240 GPa and a high hardness of 16.7 GPa. Results from this work suggest that aerodynamic levitation rapid solidification is an effective processing method to manipulate the microstructure of LLTO ceramics to minimize the GBs’ contribution to the total conductivity, which may be expanded to prepare other oxide-type lithium electrolytes.

Keywords

• LLTO
• rapid solidification
• impedance spectroscopy
• electrical conductivity