Co and F co-doping to augmenting the electrochemical performance of P2-type sodium lithium manganese oxide for sodium ion battery

P2-type sodium lithium manganese oxide is recognized as one of the most promising cathode materials for sodium-ion batteries (SIBs). However, its practical application has been hindered by poor cycling performance and limited rate capacity. In this study, we successfully co-doped cobalt (Co) and fluorine (F) into P2-type sodium lithium manganese oxide, resulting in the enhanced material CoF-NLM, which significantly improves its electrochemical performance. The CoF-NLM material exhibits several advantageous characteristics: (i) a notable increase in lattice constant and lattice cell volume, which facilitates the intercalation and deintercalation of sodium ions within its bulk structure; (ii) an enhanced surface morphology that promotes better contact between the electrode and the electrolyte; and (iii) an increased Mn3+/Mn4+ ratio, which enhances the number of active transition metal centers available for electrochemical reactions. As a result, the CoF-NLM sample demonstrates exceptional electrochemical performance, boasting a specific capacity of 135.51 mAh/g at a current density of 8 mA g−1 and maintaining an impressive 92.69 capacity retention after 100 cycles. This study conclusively demonstrates that ion doping is a highly effective strategy for enhancing the electrochemical performance of cathode electrode materials in SIBs; paving the way for the development of high-energy, high-power SIBs that can meet the demands of next-generation energy storage applications. © 2024 Elsevier B.V.