Cuprous oxide/copper particles prepared by a facile wet-chemical reduction approach as anode material for Li Ion batteries

Cu ₂O/Cu composite particles were successfully synthesized by a novel facile template-free chemical reduction route at room temperature. X-ray diffraction (XRD) results showed that the sample mainly consisted of the Cu ₂O phase coexisting with a few Cu phases. Scanning electron microscopy (SEM) images indicated that the regular particles with a cubic shape about 2-3 μm is Cu ₂O. In addition, the electrochemical behavior of the Cu ₂O/Cu composite electrode and copper electrode during the charging and discharging process were both investigated. It was found that the first discharge capacity of Cu ₂O/Cu composite electrode was up to 650 mAh·g ^-1, which is much higher than the theoretical capacity of Cu ₂O (about 375 mAh·g ^-1). The additional capacity is attributed to the electrodeposition of lithium on pure copper, confirmed by the electrochemical property of copper as the anode material of the lithium-ion battery. The copper electrode presented a high discharge capacity of 280 mAh·g ^-1 during the first cycle. However, a large irreversible capacity as same as the cuprous oxide electrode was observed during the first charging process. It is indicated that deposition of lithium on the Cu particle surface acts as a barrier preventing the contact between the Cu and the electrolyte. Furthermore, the Cu ₂O/Cu composite electrode can exhibit reversible capacity of 210 mAh·g ^-1 at a charge-discharge rate of 30 mA·g ^-1 after 40 cycles.