Lithium K-edge X-ray Absorption Analysis of Lithium-ion Battery Cathodes

Abstract

Cathode materials for lithium-ion batteries utilize oxidation/reduction reaction of metal-ion for charge storage. However, little analysis of the electronic state of lithium carrier ions has been performed. This is because there are not many methods for observing the light element lithium, and some surface films on active materials deposited after charging and discharging make the analysis of bulk structure difficult. In this study, the electronic structure change of lithium was analyzed by soft X-ray absorption spectroscopy which can directly observe the electronic state of lithium. To prevent the surface film formation, lithium was chemically extracted from LiCoO₂, LiMn₂O₄, Li_1.2Ni_0.13Co_0.13Mn_0.53O₂ of representative electrode materials.