Solid state opto-impedance of LiNiVO4 and LiMn2O4

Spinel type LiMn2O4 and inverse spinel LiNiVO4 systems serve as standard cathode materials or potential cathode systems for application in high energy density lithium-ion batteries. Upon photo-excitation using UV radiation of energy ~5 eV, the LiNiVO4 system shows significant modification in the solid state impedance pattern while the LiMn2O4 system does not. This study has revealed a significant difference in the opto-impedance pattern for LiNiVO4 with respect to LiMn2O4, which may be due to the different electronic processes involved. An attempt has been made to study this behaviour from the solid-state viewpoint.