Battery Materials Research with Muon Beam

We applied a positive muon spin rotation and relaxation (μ+SR) technique to battery materials research by investigating Li diffusion in cathode and electrolyte materials. Recently, we have found that Li diffusion in graphite, which is commonly used as an anode material in Li-ion batteries, is detectable with μ+SR. Following upon the initial μ+SR measurements on the Li intercalated graphites, C6Li and C12Li, μ+SR spectra were also measured for C12Li0.92 and C18Li0.90 posing a slightly different occupancy in the same stage structure as those of C6Li and C12Li. The temperature dependence of diffusive nature in C12Li0.92 and C18Li0.90 was found to be similar in nature to those in C6Li and C12Li. Such a diffusion was found to start to occur approximately by 50 K lower than those of C6Li and C12Li. This suggests that Li starts to diffuse at lower temperatures in the nonstoichiometric Li intercalated graphite samples than that in the stoichiometric samples.
QC 20200205