Tailoring of Li/LATP-PEO Interface via a Functional Organic Layer for High-Performance Solid Lithium Metal Batteries
Yi Rong, Zhengyi Lu, Chao Jin, Yadong Xu, Lin Peng, Ruhua Shi, Tianyi Gu, Chengyi Lu, Ruizhi Yang
Abstract
Surface functionalization is an effective strategy to reduce the chemical reactivity between a Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) electrolyte and Li metal anode and optimize the interfacial contact of different components. Herein, sodium itaconate (SI) is introduced to modify the surfaces of LATP particles (LATP@SI) via a self-polymerizing process, and a composite solid electrolyte (CSE) composed of poly(ethylene oxide) (PEO) and LATP@SI is fabricated. Benefiting from the protection of the SI nanolayer, LATP demonstrates chemical compatibility with the Li metal anode, while the reduced surface energy renders a good dispersion of LATP in PEO. Furthermore, abundant carboxyl groups in SI can offer a bridge between LATP and PEO to accelerate Li + transmission. As a result, the as-prepared PEO-LATP@SI-6 CSE exhibits a high ionic conductivity of 1.15 × 10 –4 S cm –1 at 30 °C and 1.20 × 10 –3 S cm –1 at 60 °C, a wide electrochemical stable window beyond 5.0 V, an improved Li + transference number of 0.41, and an optimized lithium compatibility over 1200 h with Li dendrite free. The as-assembled Li||PEO-LATP@SI-6 CSE||LiFePO 4 full battery delivers a high reversible capacity of 155 mAh g –1 and an outstanding capacity retention of 89% after 200 cycles. The Li||LiFePO 4 pouch cell also successfully runs 50 cycles with a terminal discharge capacity of 116.6 mA h g –1 . This study opens a new avenue to protect LATP. The developed surface functionalization technique promises a facile and efficient method for interfacial engineering to accelerate the practical application of LATP in solid-state lithium batteries.