(131e) Enhancement of Battery Performance of All-Solid-State Lithium-Ion Battery with Structural Control of Dry Coated Particls

As a promising candidate of next generation secondary battery with both high safety and high energy density, all-solid-state lithium-ion secondary batteries (ASS-LIBs) have attracted much attention. In the ASS-LIBs, inorganic solid electrolytes (SEs) are used instead of the organic liquid electrolytes. SEs are non-flammable materials and stable under higher voltage and broad temperature range. Due to these features, the ASS-LIBs are highly expected to be a next generation secondary battery for EVs. In the ASSLIBs, transfer of lithium ions during charging and discharging only occurs at the interfacial contact surface between an electrode particle (active material) and SE. Therefore, development of particle processing technologies to construct the solid-solid interfacial contacts is important issue. We reported for the first time a dry coating process to produce composite particle of electrode active material and solid electrolytes. By means of the dry coating process, lager electrode active material (core particles) were directly coated with SEs (guest particles) without using any solvents and binders, resulting the solid-solid interfacial contacts between active material and SEs within the dry coated particles. However, infulence of the structure of the dry coated particle on the battery performance has been unknown.

In this study, we have focused on the thickness of the SE layer and influence of the thickness on the battery performance was investigated. Consequently, for enhancement of the performance of the ASSLIB the thickness should be a certain optimum range, where the ion and electron conductivities can be balanced well.