Solvothermal synthesis high lithium ionic conductivity of Gd-doped Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte

Abstract

NASICON-type [Formula: see text][Formula: see text][Formula: see text]([Formula: see text] (LATP) solid electrolytes have been widely studied because of its stability in the air, low material price and high ionic conductivity. Gd-doped [Formula: see text]Al[Formula: see text][Formula: see text][Formula: see text]([Formula: see text] ([Formula: see text]= 0, 0.025, 0.05, 0.075 and 0.1) with high ionic conductivity was successfully synthesized by solvothermal method for the first time in this work. The effect of Gd doping content on the structure and electrochemical performance of solid electrolytes was systematically studied. The optimal doping content of Gd is [Formula: see text]= 0.075. With the Gd doping content of 0.075, the solid electrolyte has the highest ionic conductivity of 4.23 × 10[Formula: see text] S cm[Formula: see text] at room temperature, the lowest activation energy of 0.247 eV and the highest relative density of 94.89%. This is because the fact that when [Formula: see text]= 0.075, it is the maximum content of Gd[Formula: see text] to replace Al[Formula: see text] and can completely enter the lattice of LATP, and does not emerge too much non-lithium ion conductive GdPO4 phase.