Boosting Electrochemical Performance of Lithium-Rich Manganese-Based Cathode Materials through a Dual Modification Strategy with Defect Designing and Interface Engineering.

Low Coulombic efficiency, severe capacity fading and voltage attenuation, and poor rate performance are currently great obstacles for the industrial application of lithium-rich manganese-based cathode materials (LRMCs) in lithium-ion batteries (LIBs). Herein, a dual modification strategy combining defect designing with interface engineering is reported to solve the above problems synchronously. Oxygen vacancies, a carbon nitride protective layer, and a fast ion conductor are simultaneously introduced in the LRMCs. It has been found that oxygen vacancies can suppress the release of irreversible oxygen, which is in favor of improving the initial Coulombic efficiency, the carbon nitride protective layer can improve the structural stability and alleviate the attenuation of capacity and voltage, and the fast ion conductor can promote the diffusion rate of Li+ and electron conductivity and thus enhance the rate capability. The modified material exhibits significantly enhanced electrochemical performances, including a favorable capacity retention rate of 94.2% over 120 cycles at 1C (1C = 200 mAh g-1) and excellent rate capabilities of 173.1 and 136.9 mAh g-1 can be maintained at 5 and 10C after 100 cycles, respectively. Hence, the well-designed dual modification strategy with defect design and interface engineering provides significant exploration for the development and industrialization of LRMCs with high performance.