Studies of High-Performance Cathode Materials for Lithium-ion Batteries

Abstract

The drive to lower the consumption of fossil fuels in transportation has reached unprecedented levels due to both energy and environmental concerns. A global effort has been undertaken to develop advanced lithium-ion battery (LIB) technologies for the electrification of transportation, with the goal of significantly reducing fossil fuel consumption. In current LIBs, energy density is mainly limited by the capacity and thermodynamics of cathode materials. So improvements in cathode materials are critically needed, particularly for demanding electric vehicle applications. The studies have focused on a series of high-performance cathode materials for LIBs. Key synthesis parameters including pH, stirring rate and calcination temperature have been fully optimized for the LiNi0.6Mn0.2Co0.2O2 cathode material using a co-precipitation-calcination two-step scalable process. A high-rate performance LiNi0.33Mn0.33Co0.33O2 cathode material with preferentially orientated lithium-diffusing channels also successfully developed. In addition, the carbon fiber decorated Ni-rich LiNi0.88Mn0.06Co0.06O2 composites, exhibited enhanced rate capability and stability due to the faster ionic/electronic diffusion and shorter diffusion path benefited from the carbon fiber network structure. Finally, a class of high-energy phenothiazine-derived redox-active polymers that deliver high capacities at ultrafast discharge rates have been studied.