Spray Pyrolysis Synthesis of Li2O-V2O5-B2O3 Glass for the Low-Temperature Sintering of LATP Electrolytes in Solid-State Lithium Metal Batteries.

NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) is a promising solid-state electrolyte for lithium metal batteries (SSLMBs) due to its high ionic conductivity and stability. However, its high sintering temperature (800-900 °C) leads to lithium volatilization, the formation of secondary phases, and considerable energy consumption. Lowering the sintering temperature is also important for the practical application of LATP in all-solid-state batteries (ASSBs), particularly for facilitating integration with LATP-cathode composites. Herein, an amorphous Li2O-V2O5-B2O3 (LVBO) glass powder with spherical morphology is synthesized via spray pyrolysis at 900 °C and used as a sintering aid at loadings of 0.0-1.5 wt.% to enable low-temperature liquid-phase sintering of LATP at 650 °C. The addition of LVBO glass to LATP increases the relative density from 83.45% to 91.56% and enhances the ionic conductivity from 1.68 × 10-4 to 3.54 × 10-4 S cm-1. The LATP pellet with 1.0 wt.% LVBO (LATP-1.0) exhibits a critical current density (CCD) of 1.25 mA cm-2 in symmetric lithium cells. LiFePO4(LFP)|LATP-1.0|Li full cells deliver excellent rate capabilities up to 1.0 C, whereas the full cell with pristine LATP fails at 0.2 C. This study establishes strategies for simultaneously reducing the sintering temperature and enhancing the electrochemical performance of LATP for SSLMBs.