Background

All-solid-state batteries that use solid electrolytes are superior to existing lithium ion batteries that use liquid electrolytes in terms of safety, higher capacity, and reduced size. Battery performance is closely related to changes in the crystal phase of the positive electrode material during charge and discharge cycles; therefore, operando measurements using short-wavelength X-rays with high penetration power are being actively conducted. In addition to Mo radiation, Ag radiation can be used as a short wavelength X-ray source. By combining Ag radiation and convergent beam optics, operando measurements can be performed by transmission geometry even for all-solid-state batteries where sample absorption is significant.