(738g) Design of All-Solid-State Lithium-Ion Battery Based on Particle Coating Technology

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 here propose to use a dry coating process to produce composite particle of electrode active material and solid electrolytes. In the dry coating process, lager electrode active material (core particles) were directly coated with SEs (guest particles) by mechanical forces without using any solvents and binders. As a result, FESEM and EDX images showed that the active material were almost fully covered with SEs without breakage of the active material, indicating that the solid-solid interfacial contacts between active material and SEs were constructed within a primary composite particle. A performance of ASS-LIB-test-cell exhibited remarkable improvement when the dry coated particles were used. It was concluded that the dry coating process is very effective to produce composite particle for electrode of ASS-LIBs.