Research progress on lithium-rich cathode materials for high energy density lithium-ion batteries

The rapid development of lithium-ion batteries (LIBs) has been a great driving force for the progress of human society. The continuous development of electric vehicles, power grids, electronic products and other industries all have an increasing demand for high energy density batteries. The primary factor limiting the development of LIBs that have high energy and low cost is the cathode material. In the existing cathode materials, the Lithium-rich (Li-rich) cathodes compensate for capacity by redox reactions involving anions and cations, which have become the ideal cathode materials for the future LIBs due to their ultra-high specific capacity and energy density. However, the problems such as structural deterioration and lattice oxygen evolution during the cycle of Li-rich cathodes have seriously hindered the commercialization of Li-rich cathodes. Therefore, this paper has discussed the factors leading to the degradation of the electrochemical performance of Li-rich cathodes from the aspects of electron energy state and microstructure. Meanwhile, it also discussed the latest development in the modification and analysis of Li-rich cathodes including multifunctional surfaces, gradient doping and high entropy doping matters, in order to provide useful insights into the future preparation and modification of these cathodes.