蓄電池および関連材料研究への中性子線の応用

抄録

Neutron diffraction techniques were used for the studies of battery and related materials. The static crystal structure of super lithium ionic conductors as a solid-state electrolyte are very precious information to improve their lithium conductivity. The highest super lithium ionic conductor, Li₁₀GeP₂S₁₂ was discovered in 2011. Its unknown structure was determined by neutron diffraction. This determined structure was led to the improved materials (Li_9.54Si_1.74P_1.44S_11.7Cl_0.3, Li_9.6P₃S₁₂) which have higher values of the lithium ionic conductivities. Furthermore, a fabricated all-solid-state cell based on the developed lithium conductors showed outstanding battery performances against ones of the current commercialized battery. In addition, an operando diffraction technique on the new developed neutron diffractometer dedicated for battery study in J-PARC, was developed to understand the structural changes of cathodes and anodes during charge–discharge processes in battery. By this technique, relaxation process after a high discharge rate and inhomogeneous structural changes depended on the discharge rates were observed. This information gave new understandings of battery reaction and opened the way for the development of a new advanced battery.