Mg2+/Al3+ Co-doped Li-Rich Manganese-Based Oxides for Boosting Rate Performance and Stability of Lithium-Ion Batteries

Abstract

Lithium-rich manganese-based oxides (LRMOs) are promising cathode materials for lithium-ion batteries (LIBs) due to their high energy density. However, their practical application is limited by poor rate performance and rapid capacity fading. Single elemental doping of LRMOs has only partly addressed these issues. In this study, a Mg²⁺/Al³⁺ co-doping strategy is introduced to modify LRMO cathode materials. The theoretical and experimental investigations confirm that the proposed Mg²⁺/Al³⁺ co-doping strategy can regulate the atomic configuration and spatial lattice structure, induce a coupling mechanism that promotes Li⁺ diffusion kinetics, and enhance the overall lattice structural stability. As a result, the Mg²⁺/Al³⁺ co-doped LRMO exhibits a high initial reversible capacity of 269.9 mAh g⁻¹, superior rate capability with 160.7 mAh g⁻¹ at 5.0C, and excellent cycling stability with 90.0% capacity retention after 200 cycles at 1.0C. Furthermore, the co-doped LRMO pouch full cell delivers outstanding long-term cycling performance. The success of this work suggests that Mg²⁺/Al³⁺ co-doping could be an excellent strategy to advance the LRMO cathode materials for high-capacity LIBs.