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

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.