Electrochemical Performance of Full Concentration Gradient Cathode for Lithium-Ion Batteries
Recently, some novel design structures cathode material are reported, such as core-shell, gradient material. First, a co-precipitation process is used to synthesize core-shell or gradient structure spherical precursor, then using this precursor to prepare a same structure cathode material. Using this new process, it is easy to control the elements distribution inside of single particles. This concept make it is possible to achieve the high capacity, cycling life and safety for a cathode material. So the composition design is based on those, high Ni in bulk material for high capacity and high Mn on the surface for safety with certain Co are investigated.
In this study, we investigated a full concentration gradient material, and the average composition is closed to Li1.0Ni0.6Co0.2Mn0.2O2. The material was synthesized by a solid-state reaction from full concentration gradient spherical precursor Ni0.6Co0.2Mn0.2(OH)2 and LiOH precursors. The full concentration gradient spherical precursor Ni0.6Co0.2Mn0.2(OH)2was prepared by a co-precipitation process. It exhibited uniform spherical particle shape with 15-mm diameter and high tap density of 2.7 g/cc. The electrochemical performance of the material was evaluated in a coin-cell. When the current density was 16 mA/g (C/10), the discharge capacities were about 191 mAh/g.
The significant improvement in tap density and the high capacity of this material makes it a potential cathode material for high energy battery application.