A higher redox potential of solid state oxygen redox in Li4SiO4–LiCoO2 nano composite cathode

Abstract

Modern and futuristic products, such as electric and hybrid electric vehicles, require high-capacity batteries. Solid state oxygen redox-type active materials are candidate as high-capacity positive electrode materials for Li-ion batteries. A promising high-capacity cathode material for Li-ion batteries is Li4SiO4 that can have higher redox potential compared with other Li2O-based materials. In this study, anion redox of Li4SiO4 was activated by nano-compositing with LiCoO2 via mechanical alloying. The nano composite cathode exhibits a specific capacity of ∼220 mAh g−1 with ∼0.5 V higher redox potential than that of Li2O-based cathode materials. X-ray absorption/photoelectron spectroscopy analyses show that the redox reaction of oxygen, including the formation and decomposition of superoxide and peroxide, is responsible for the charge compensation in the nano-composite cathode.