Main issues for lithium ion batteries (LIBs) to grow in the application to advanced vehicles are durability, safety and cost. The durability is closely connected with safety, cost, energy density, etc.

LIBs are constructed by composite electrodes both of positive and negative electrodes, which are composed of pulverized active materials, conductive additives, and binders. The structure of LIBs is thus complicated and reaction distribution inside battery and composite electrodes often occurs. Uniform reactions distribution leads to the maximum performance of the battery. Many factors give major influences on the reaction distribution. Analytical methods to elucidate the reaction distribution were limited. In RISING project, different kinds of operando analytical technologies were developed. In the present work, some methods using SR X-ray devised in RISING are introduced and reaction distributions clarified by using this technology are explained mainly on positive electrode of layered and olivine type materials.

Acknowledgment

This work was supported by RISING of NEDO.