Interfacial Architecture for Extra Li+ Storage in All-Solid-State Lithium Batteries

Abstract

The performance of nanocomposite electrodes prepared by controlled ball-milling of TiS₂ and a Li₂S-P₂S₅ solid electrolyte (SE) for all-solid-state lithium batteries is investigated, focusing on the evolution of the microstructure. Compared to the manually mixed electrodes, the ball-milled electrodes exhibit abnormally increased first-charge capacities of 416 mA h g(-1) and 837 mA h g(-1) in the voltage ranges 1.5-3.0 V and 1.0-3.0 V, respectively, at 50 mA g(-1) and 30°C. The ball-milled electrodes also show excellent capacity retention of 95% in the 1.5-3.0 V range after 60 cycles as compared to the manually mixed electrodes. More importantly, a variety of characterization techniques show that the origin of the extra Li(+) storage is associated with an amorphous Li-Ti-P-S phase formed during the controlled ball-milling process.