Improved rate capability of LiCoO2 cathode material via particle size-control for Li-ion Batteries

Abstract

For those several decades, alternative energy production and energy storage system has been actively studied due to dramatic growing of worldwide energy demands and strengthened enviromnetal regulations. Lithium-ion batteries (LIBs) have been spotlighted as a next generation energy storage system. Because lithium is the most electropositive and lightest metal, thus it has a higher volumetric and gravimetric energy density than others regardless of cell types.

Layered metal oxides have been used for Li-ion battery cathodes as most popular source since the first commercial battery launched by Sony in 1991. LiCoO2 is the most popular cathode material having layered structure. It is practically and widely used in the secondary battery fields for portable devices, due to its advantages. It is easy to manufacture LiCoO2 compared to other cathode materials, leading to facilitate mass production. General manufacturing conducted by conventional solid-state calcination using lithium source and cobalt oxide with stoichiometric calculation.

To enhance the rate capability of electrode material, there are several methods such as coating, doping and down-sizing representatively. Herein, we tried to develop the LiCoO2 material showing stable charge rate performance at high rate. The single crystal with big size morphology usually has good electric conductivity and relatively lower ionic conductivity. In contrast, polycrystalline shows vice versa. Therefore, in this experiment we suggested the spherical secondary particle to secure porosity and better tap density compared to existing down-sized particles at the same time.