One-pot solvothermal synthesis of Co1−xMnxC2O4 and their application as anode materials for lithium-ion batteries

Abstract

A facile one-pot solvothermal route has been developed to synthesize phase pure MxC2O4⋅2H2O (M=Mn, Co; 0<x⩽1) microstructures without employing any hard/soft template and their electrochemical performance in lithium-ion batteries has been systematically investigated. Morphology, microstructure and composition of the synthesized materials are characterized by field emission-scanning electron microscopy, X-ray diffraction and energy-dispersive X-ray spectroscopy. Anhydrous micron-sized MnC2O4 and CoC2O4 exhibits specific reversible discharge capacity of ∼800 and 950mAhg−1 respectively, at 1C-rate. MnC2O4 exhibited good cycling stability while CoC2O4 showed severe capacity fading phenomenon after 40 cycles, thereafter attaining 400–600mAhg−1 for all C-rates. Interestingly, mixed solid solution having Co0.52Mn0.48C2O4 composition improved the specific reversible discharge capacity to a stable value of ∼1000mAhg−1 (1C-rate), which is one of the highest reported values for such oxalates. The cycling stability of this mixed metal oxalate is remarkably better than its individual constituents at most C-rates. The Mn2+ substitution into CoC2O4 lattice has led to the synergistic modification of the electrochemical performances, thus making it a promising anode candidate for future LIBs.