Low-temperature fabrication of NASICON-type LATP with superior ionic conductivity

NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) has attracted much attention as a fast lithium-ion conductor for all-solid-state lithium-based batteries. However, the large grain-boundary resistance and high sintering temperature above 950 °C for pure LATP electrolytes hinder their practical application in lithium-based batteries. Here, a low-temperature preparation approach for the superionic conductor LATP electrolyte with sintering aids is proposed. By introducing sintering aids Li 3 PO 4 , LiBO 2 ·0.3H 2 O, and binary 0.32Li 3 PO 4 -0.68LiBO 2 ·0.3H 2 O, LATP-based pellets can be fabricated at optimized sintering temperatures below 900 °C. The resultant LATP-based pellets maintain a high relative density and homogeneous microstructure, which arises from the sintering aid to facilitate the grain rearrangement and fill the interstices between grains. The LATP pellets using sintering aid Li 3 PO 4 achieve a high ionic conductivity of 5.2 × 10 −4  S cm −1 at a low temperature of 800 °C, 7.3 times that (7.1 × 10 −5  S cm −1 ) of pure LATP pellets sintered at 950 °C, which demonstrates the effectiveness of low-temperature preparation approach to reducing the preparation cost and optimizing the ionic conductivity of LATP-based electrolytes.