Facile synthesis of Cu2O nano-microspheres anode for lithium-ion batteries

Transition metal oxide anode materials exhibit high theoretical specific capacities and can meet the energy density requirements through reasonable design. In this work, a facile wet-chemical method to fabricate Cu₂O nano-microspheres anode for lithium-ion batteries with controllable size varied from 0.4 ∼ 1.2 μm is introduced, which basically using copper acetate as copper precursor and ascorbic acid as reducing agent. The solvent composition (DI water only or DI water:Ethanol = 1:1), solution alkalinity (amount of NaOH input), and synthesis temperature are investigated as factors affecting the size and morphology of Cu₂O nano-microspheres. The samples are characterized by X-ray diffraction, transmission electron microscope and scanning electron microscope. Nanoparticle cluster structure is observed in the reaction product with the bi-solvent system. With the optimized synthesis condition, the prepared Cu₂O anode (size of ∼ 455 ± 41 nm) delivers an initial discharge capacity of 539 mAh/g at a current density of 0.5C, 100 cycles of cyclic discharge at 0.5C with a capacity retention rate of 84.73 %. At the current density of 2C, the specific capacity is 347 mAh/g. Even at a large current density of 5C, the specific capacity is still as high as 219 mAh/g, indicating good rate capability.