Binary Cu/ZnO decorated graphene nanocomposites as an efficient anode for lithium ion batteries

Binary metal/metal oxide doped graphene nanocomposites have received wide attention as an effective anode material in Li-ion batteries. The binary composition metal/metal oxide improves the storage space and the conductivity of the electrode. The doped graphene enhances the structural and electronic properties of the electrode. In the present work, we report a Cu/ZnO hybrid nanoparticle-decorated graphene nanocomposite as an advanced anode material for the high-performance Li-ion batteries. Three different compositions of the hybrid Cu/ZnO/graphene nanocomposites have been synthesized by changing the concentration of Cu precursors in the hybrid. The nanocomposite of 0.05 M Cu precursor and 0.1 M ZnO precursor shows higher surface area (S_BET = 168.7 g/m²) and excellent electrochemical results. X-ray photoelectron spectroscopy (XPS) analysis revealed that the Cu nanoparticle exists in +2 oxidation state on the ZnO lattice with the graphene nanostructure. Transmission electron microscopy (TEM) analysis shows the distribution of Cu/ZnO nanoparticles over the graphene sheets with a size of around 10–50 nm. From the electrochemical analysis, we inferred that the hybrid possesses a stable and specific capacity of 630 mAh g⁻¹ at a current rate of 100 mA g⁻¹ with almost 95% capacity retention for up to 100 cycles. To highlight the importance of binary Cu/ZnO doped graphene nanocomposites, their respective base namely, ZnO/graphene and Cu/graphene composites have also been studied.