<i>Operando</i> Soft X-ray Absorption Spectroscopic Study of an All-solid-state Lithium-ion Battery Using a NASICON-type Lithium Conductive Glass Ceramic Sheet

An electrochemical cell was developed for operando soft X-ray absorption spectroscopic (XAS) study of an all-solid-state lithium-ion battery. Operando XAS experiments were performed for a battery using LiMn2O4 as a cathode material and a NASICON-type lithium conductive glass ceramic sheet (LICGC) as a solid electrolyte. O K-edge, Mn L-edge and Ti L-edge XAS spectra were taken during the charging process up to 2.2 V. Detailed analysis of the XAS spectra revealed that the valence change from Mn3+ to Mn4+ occurred during charge with simultaneous change in the spectrum of O K-pre-edge region. Ti L-edge spectra revealed a partial change from Ti4+ to Ti3+ in the LICGC at the anode side, indicating a rather dispersed anode formation.