Binder-free three-dimensional porous structured metal oxides as anode for high performance lithium-ion battery

Three-dimensional porous Cu/Cu2O, CuO, CuO/NiO were prepared on Ni foam by a simple two step method which consist of a replacement reaction and subsequent thermal treatment method at various temperature. The morphology and microstructure of the samples were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical properties of the samples were evaluated by galvanostatic discharge-charge cycling, cyclic voltammetry and impedance spectral measurements on cells with lithium discs as counter electrode and reference electrode. Compared to Cu/Cu2O and CuO/NiO, the sample of CuO obtained at 400 °C exhibited the best electrochemical performance which delivered a reversible capacity of 605.3 mAh g−1 (89.8% of the theoretical capacity) after 50 cycles at the current density of 100 mA g−1, without noticeable capacity fading. The excellent electrochemical performance of porous CuO can be attributed to the three-dimensional porous structure, which cannot only provide large surface area but also facilitate Li+ and electron transfer, and the strong connection between active materials and Ni foam can promote better intrinsic kinetics.