リチウムイオン電池研究におけるミュオンの活用

抄録

We have used muons for an analysis of battery to improve its safety and performance in two ways; one is muon spin rotation and relaxation (μSR) with positive muons to study the diffusion of lithium (Li) in Li-ion battery materials. The dynamics of Li ion can be investigated through the response of muons to the internal magnetic field provided by the nuclear moment of the Li ion. The other is a non-destructive observation using negative muons. Since the muon-characteristic X-rays generated by negative muon irradiation have about 200 times higher energy than fluorescent X-rays, muonic X-rays from Li can penetrate from its housing. Recently, this technology has been successfully applied to the detection of metallic Li in a battery, and we hope that it will be further utilized for safety.