Porous CoO/C polyhedra as anode material for Li-ion batteries

•Porous CoO/C polyhedra were synthesized by reducing Co3O4 polyhedra with sugar.•The CoO/C polyhedra exhibited an initial discharge capacity of 1025 mAh g−1.•Coulombic efficiency over 99% and improved rate capability were achieved for the CoO/C polyhedra.•Porous and hierarchical structure was responsible for the improved electrochemical performance.

Uniform, hierarchical and porous CoO/C polyhedra were synthesized by impregnating hydrothermally fabricated Co3O4 polyhedra with sugar solution followed by calcination in inert atmosphere. Each CoO/C polyhedron was built up of numerous ordered nanoparticles (around 100 nm). As anode material for Li-ion batteries, the CoO/C polyhedra exhibited an initial discharge capacity of 1025 mAh g−1, and remained a reversible capacity of 510 mAh g−1 after 50 cycles at a current density of 100 mA g−1. High Coulombic efficiency over 99% and improved rate capability were achieved for the CoO/C polyhedra. Hierarchical structure and high porosity was benefit to the infiltration of electrolyte and tolerant volume expansion, and hence was responsible for the good electrochemical performance.

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