Temperature-Engineered MnO/Mn3O4/C Composites Derived from DMAc for High-Performance Lithium-Ion Batteries

초록

Mixed-valence MnO/Mn3O4/carbon (MnO/Mn3O4/C) composites were synthesized via a one-step solvothermal process followed by thermal annealing, utilizing N,N-dimethylacetamide (DMAc) as a dual-function solvent and in-situ carbon source. By precisely tuning the annealing temperature, the structural and electrochemical properties of the resulting composites were optimized. Notably, the sample annealed at 500 degrees C (Mn-N5) exhibited a balanced Mn2+/Mn3+ ratio, abundant oxygen vacancies, and a conductive sp(2)-rich carbon framework. These features collectively enhanced lithium-ion diffusion, electron transport, and mechanical integrity. As an anode material, Mn-N5 delivered a high reversible capacity of 861 mAh g(-1) at 0.2 A g(-1), retained 309 mAh g(-1) at 2 A g(-1), and maintained 473 mAh g(-1) after 1000 cycles at 0.5 A g(-1). Kinetic analysis and impedance spectroscopy confirmed improved charge transfer and pseudocapacitive behavior, driven by the synergistic effects of the heterostructured MnOx and carbon network. These results demonstrate a scalable and cost-effective strategy for engineering high-performance Mn-based anodes suitable for next-generation lithium-ion batteries.

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