High Performance Nanostructured Phospho-olivine Cathodes for Lithium-ion Batteries

Abstract

Materials innovation has been the key to Next generation of high performance lithium ion batteries. The need for high energy density, high power density, low cost and environmental benign electrodes has identified the phospho-olivine cathodes as substitutes to the costly and toxic LiCoO2 based cathodes. However, the performance of the phospho-olivine cathodes has been largely impeded by their slow electrode reaction kinetics.

This thesis is focused on the innovation of design and synthesis of phospho-olivine cathodes for high rate and stable cycle performance. Combinatorial strategies employing the compositional and structural engineering techniques were incorporated in the phospho-olivine cathode design. Through a successful combination of bulk property engineering (size reduction, element doping), surface modification (thickness and uniformity controlled carbon coating) and nanostructuring (nanocrystal aggregates, carbon network embedding, and porosity), the synergistic coupling of these features effectively enhanced the electrochemical performance of the phospho-olivine cathodes for high rate and long life applications.