全固体電池に用いる硫化物系固体電解質粉体の湿式粉砕と活物質－固体電解質乾式コーティングへの応用

抄録

In this study, we investigated milling characteristics of sulfide solid electrolytes (SEs) for all-sold-state lithium ion batteries (ASSLIBs). Subsequently, we employed the milled SEs as guest particles for dry coating of cathode active material (AM), and examined the influence of SE size distribution on ASSLIB performance. Our finding revealed that SE particles have unique milling characteristics, in which coalescence of milled fine particles occurs simultaneously with size reduction by milling. The dry coating experiments confirmed that the use of milled SEs (guest particles) resulted in more uniform coating of the AM (host particles) with SE, leading to significant improvement in the performance of ASSLIB (630% increase in capacity as compared to unmilled SEs). However, when SEs were excessively milled, the SE coating layer exhibited non-uniform morphology, resulting in lower battery performance (15% decrease in capacity). Consequently, our results highlighted that there is an optimal milling condition for SE guest particle for the dry coating.