抄録
Understanding the reaction processes that can affect crystal structure and thermodynamics is important to improve the characteristics of highly functional oxides. During the charge–discharge processes of lithium-ion battery cathode materials, structural changes that accompany lithium intercalation and deintercalation are important factors that govern the characteristics. An original thermodynamic analysis of these processes was adopted and structural analysis using neutron diffraction during the charge–discharge process was successfully conducted for the first time to identify the structural changes in a coin cell-sized cathode. Structural analysis also employed quantum beams (neutron, synchrotron radiation), and the bonding characteristics were investigated with the maximum entropy method (MEM) by determination of the electron density distribution. Moreover, a pioneering application of the crystal pair distribution function (PDF) analysis for the bulk material together with X-ray absorption fine structure (XAFS) analysis enabled examination of the local structural changes that average structural analyses could not reveal. The diversified approach of this research involved a combination of these methods. Consequently, the structural and thermodynamic stability were determined to be important for improvement of the characteristics of highly functional oxides.
