Facile Synthesis of Sponge-like Microstructured CuO Anode Material for Rechargeable Lithium-Ion Batteries

CuO was synthesized by employing the facile chemical precipitation technique to vary the concentrations of Cu(NO3)2 in a range from 0.001 to 0.1 M. This was carried out in order to find the concentration of Cu(NO3)2 that results in optimal electrochemical performance in CuO as an anode electrode material for lithium-ion batteries. Among the investigated concentrations, the 0.03 M Cu(NO3)2 showed the best electrochemical performance. Of the synthesized materials, the scanning electron microscopic (SEM) analysis revealed the existence of a sponge-like morphology. X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), synchrotron X-ray diffraction (SXRD) and Raman spectrum confirmed the formation of a required CuO phase. The electron density distribution on the crystalline structure of the synthesized CuO indicates the existence of the highest distribution of electrons around Cu atoms, with enhanced productivity of the conversion mechanism during the cycling process. Further, this study shows that the electronic interfacial properties of Cu/CuO could be improved by optimizing the amount of acetylene black used for the electrode fabrication, with 20 wt% being the optimum value. The electrodes fabricated with the synthesized sponge-like microstructured CuO as the active material exhibited a high initial specific discharge capacity of 3371.9 mA h g−1 and resulted in a specific discharge capacity of 442.9 mA h g−1 (Coulombic efficiency of 97.4%) after 50 cycles, at a rate of 0.2 C. Moreover, the specific discharge capacity reported at the rate of 1.0 C was 217.6 mA h g−1 with a significantly high Coulombic efficiency of about 98.0% after 50 cycles. Altogether, this study reveals the high potentiality of using sponge-like microstructured CuO as a high-performance anode electrode material for LIBs.