Enhanced electrochemical performance of La and F co-modified Ni-rich cathode

With the development of the times, the energy density of cathodes can no longer meet the requirement of the society, which has greatly limited the commercialization process of Ni-rich cathodes. Doping combined with coating is a perfect approach to improve the performance of Ni-rich cathodes. In this paper, La was used as a modified element to realize doping in the layered host structure as well as La2O3 coating on the surface. To further enhance the interface stability of LiNi0.8Co0.1Mn0.1O2, F was also employed to modify the surface, so as to change the coating layer from oxide (La2O3) to fluoride (LaF3), which further improved the surface stability. Additionally, a series of testing instruments, including XRD, EDS mapping, and HRTEM, were employed, which suggested that a small amount of La was introduced into the host structure as a pillar to the stable layered structure, and there was an uniform LaF3 coating layer covered on the Ni-rich cathodes. As a result, the electrochemical performance of the cathodes was greatly improved, with the capacity retention of 86.63% and 80.79% after 200 cycles at 1 C rate and 300 cycles at 8 C rate, respectively; besides, the kinetics of lithium diffusion was also improved.