Realizing primary/secondary particle co-coating with CoxB for lithium-rich cathodes in high-performance lithium-ion batteries

Abstract

The construction of a surface protection layer is an important way to improve the cycling stability of lithium-rich manganese-based cathode materials. However, the protection for the primary particles inside is usually neglected compared with the secondary particles, which increases the corrosion risk of the electrolytes. In view of this, amorphous CoxB coated Li1.2Mn0.54Ni0.13Co0.13O2 (LMNCO) was rationally designed and prepared. Nano CoxB not only completely coated the surface of the secondary particles but also penetrated between the grain boundaries of the primary particles to achieve the protection of the primary particles. Thus, the cycling stability of the LMNCO is improved significantly. After 200 cycles at 1C and 25°C, the capacity loss rate of CoxB-LMNCO is 8.9%. Even at 2C and 40°C, the value is only 13.4%. As a result, this work provides a new idea to improve the electrochemical performances of the LMNCO cathode materials in high-performance lithium-ion batteries.