Proton solvent-controllable synthesis of manganese oxalate anode material for lithium-ion batteries

Abstract

Manganese oxalates with different structures and morphologies were prepared by the precipitation method in a mixture of dimethyl sulfoxide (DMSO) and proton solvents. The proton solvents play a key role in determining the structures and morphologies of manganese oxalate. Monoclinic MnC2O4·2H2O microrods are prepared in H2O-DMSO, while MnC2O4·H2O nanorods and nanosheets with low crystallinity are synthesized in ethylene glycol-DMSO and ethanol-DMSO, respectively. The corresponding dehydrated products are mesoporous MnC2O4microrods, nanorods, and nanosheets, respectively. When used as anode material for Li-ion batteries, mesoporous MnC2O4microrods, nanorods, and nanosheets deliver a capacity of 800, 838, and 548 mA h g−1after 120 cycles at 8C, respectively. Even when charged/discharged at 20C, mesoporous MnC2O4nanorods still provide a reversible capacity of 647 mA h g−1after 600 cycles, exhibiting better rater performance and cycling stability. The electrochemical performance is greatly influenced by the synergistic effect of surface area, morphology, and size. Therefore, the mesoporous MnC2O4nanorods are a promising anode material for Li-ion batteries due to their good cycle stability and rate performance.