Facile synthesis of NASICON-type Li1.3Al0.3Ti1.7(PO4)3 solid electrolyte and its application for enhanced cyclic performance in lithium ion batteries through the introduction of an artificial Li3PO4 SEI layer

Abstract

The pure Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP) ceramic powders with uniform distribution have been successfully synthesized with CO(NH₂)₂ as a molten flux at a relatively lower temperature compared to conventional methods. The influences of the molar ratio of molten CO(NH₂)₂ to reaction precursor, calcination temperature for the LATP powders and the sintering temperature for the LATP pellets are investigated; the pellet with the highest total conductivity of 7.02 × 10⁻⁴ S cm⁻¹ at room temperature is obtained. In addition, in view of the instability between LATP and metallic lithium, we introduce an artificial Li₃PO₄ SEI (solid electrolyte interphase) layer to block the contacts between them. The results of galvanostatic charge–discharge measurement show that the as-assembled battery delivers an excellent capacity retention ratio of 95.2% at 0.1C rate after 50 cycles, which is much higher than untreated samples. We conclude that adding an artificial Li₃PO₄ SEI layer is an effective way to improve the electrochemical property of solid state lithium ion batteries (LIBs) with LATP as an electrolyte.