Defect and Structural Evolution during the Synthesis/Charging of Layered Li(Ni,Co,Mn)O2 Oxides

Abstract

With the increasing awareness of environmental protection, the installation of renewable energy including solar cells and wind mills has become the priority in government development policy. Due to the intermittent nature of renewable energy, a good energy storage system such as Li ion batteries is needed. The cost of cathode materials may take as much as 50% based on the breakdown of the whole battery. Recently, the single-crystal process of layered oxides received great attention due to its better electrochemical performance. For NMC layered oxides, multiple-step co-precipitation process is commonly used. In additions, “single-crystal” process typically requires more heat energy at higher temperatures. Therefore, the main objective of this study is to develop a cost-effective process for the synthesis of single-crystal Ni-rich layered oxides electrode. For instance, the synthesis of layered oxides may adopt the simple solid state reaction routes. The heating procedures may be optimized through the understanding of calcination and grain-growth processes. Ni-rich layered oxides, namely NCA and NMC 811 are selected and prepared. The crystal structure and microstructure of cathodes were examined using XRD and SEM. The electrochemical properties are monitored using CV, EIS and charge/discharge tests.