In situ formed amorphous carbon-coated LiMn₂O₄ cathode with long-term stability for lithium-ion batteries

Spinel LiMn₂O₄ is one of the most promising cathode materials due to its green, low-cost, and abundant resources. However, issues such as manganese dissolution, electrolyte decomposition, and inadequate cycling stability have hampered its further application. Herein, we designed a modification strategy for LiMn₂O₄ cathodes using N-methyl-2-pyrrolidone (NMP), water, and ethanol mixed solution as the carbon source to in situ coat LiMn₂O₄ truncated octahedra particles. It is found that the amorphous carbon layer serves as a structure stabilization agent to enhance the electrochemical performance of LiMn₂O₄. Specifically, the coating carbon layer can effectively minimize the acid corrosion, facilitate Li⁺ diffusion, improve the interface between the electrode and electrolyte, and strengthen cycle stability. As a result of these improvements, the optimized 2 mL C/LiMn₂O₄ sample exhibits outstanding long-term performance, with an initial discharge specific capacity of 107.6 mAh g^-1 and a capacity retention of 50.56% after 2000 cycles at 10C. This outstanding performance makes our material a promising candidate cathode for lithium-ion battery in future applications.