Trap State Spectroscopy of LiMyMn2-yO4 (M = Mn, Ni, Co): Guiding Principles for Electrochemical Performance

Trap state spectroscopic studies on LiMyMn2-yO4 (M = Mn, Ni, Co) using the opto-impedance technique revealed that LiMn2O4, LiNiyMn2-yO4 and LiCo1/6Mn11/6O4 respectively exhibit the phenomena of photoconductivity, photoresistivity, and photoneutrality. An attempt is made in this work to understand the photosensitivity in these materials on the basis of their trap state structure. The material LiCo1/6Mn11/6O4 which is robust toward an optical perturbation is also interestingly stable, compared to the other materials, toward repeated electrochemical charge and discharge.