HIGH-CAPACITY LAYERED CATHODE MATERIALS FOR HIGH-ENERGY LI-ION BATTERIES

Abstract

To achieve high energy density, LIBs must be designed on materials level as well as on system level. This research aims at one of the key components in LIBs, namely cathode materials, in particular layer-structured materials that have received great interests due to their high theoretical and reversible capacities. Therefore, in this study nickel-based layer-structured cathode materials with high redox value provided by Ni3+/Ni4+ redox couple are studied. Another strategy to improve the capability is by increasing the Li content in the layer-structured cathode materials. Anion doping retards the phase transformation so as to stabilize the energy density. Furthermore, a surface modification strategy is proposed to enhance the rate capability of Li-rich layered cathodes, which involves a similar phase transformation but only in surface regions.