Structural evolution of nickel-rich layered cathode material LiNi0.8Co0.1Mn0.1O2 at different current rates

Ni-rich layered oxide LiNi0.8Co0.1Mn0.1O2 has received considerable attention in the research field. However, the structural transformation of Ni-rich material is different at different cycling rates, and investigating the evolution of its structures to further enhance the electrochemical properties of the material seems of great significance. Therefore, the structural evolution of LiNi0.8Co0.1Mn0.1O2 materials is analyzed at different cycling rates. Results display that LiNi0.8Co0.1Mn0.1O2 materials will produce diverse phases at different cycling rates. At low cycling rates, there are enough Li vacancies in the materials to facilitate the complete mixing of transition metals and Li+, which leads the LiNi0.8Co0.1Mn0.1O2 materials to evolve from a layered structure to a rock salt phase structure. At high rates, the lack of vacancies caused by the sluggish dynamics will lead to the evolution of Ni-rich materials from a layered structure to a spinel structure. The electrochemical performances further show that about 78.23% of the capacity is maintained after 300 cycles at low rate of 1 C, which is much higher than that of 65.76% at high rate of 2 C. The results show that, compared to high-rate charge and discharge, the excellent electrochemical performance of low-rate charge and discharge is because it is easier to form a stable rock salt phase layer on the surface of the material at low rates, which effectively maintains the integrity of particles and better maintain the lithium-ion transmission rate of LiNi0.8Co0.1Mn0.1O2.

Automated summary

The structural evolution of Ni-rich layered oxide LiNi0.8Co0.1Mn0.1O2 at different cycling rates shows that at low rates, the material evolves from a layered structure to a rock salt phase structure, while at high rates, it evolves to a spinel structure. Electrochemical performances reveal that maintaining capacity is higher at low rates (78.23% after 300 cycles at 1 C) than at high rates (65.76% at 2 C). This suggests that forming a stable rock salt phase layer on the material's surface at low rates helps maintain particle integrity and lithium-ion transmission rate better.