High reversible capacity and rate capability of ZnCo2O4/graphene nanocomposite anode for high performance lithium ion batteries

• ZnCo2O4 nanoparticle was first synthesized by low cost facile urea-assisted combustion method.
• The nanocomposite was synthesized by 30 s spex milling of ZnCo2O4 and graphene.
• The nanocomposite anode exhibited one of best electrochemical properties among reported data.
• Excellent performance can be attributed to synergistic effect between ZnCo2O4 and graphene.
• Simple, low cost and short-time synthesis is attractive for practical application in large scale.

A facile and straightforward method was adopted to synthesize ZnCo2O4/graphene nanocomposite anode. In the first step, pure ZnCo2O4 nanoparticles were synthesized using urea-assisted auto-combustion synthesis followed by annealing at a low temperature of 400 °C. In the second step, in order to synthesize ZnCo2O4/graphene nanocomposite, the obtained pure ZnCo2O4 nanoparticles were milled with 10 wt% reduced graphene nanosheets using high energy spex mill for 30 s. The ZnCo2O4 nanoparticles, with particle sizes of 25–50 nm, were uniformly dispersed and anchored on the reduced graphene nanosheets. Compared with pure ZnCo2O4 nanoparticles anode, significant improvements in the electrochemical performance of the nanocomposite anode were obtained. The resulting nanocomposite delivered a reversible capacity of 1124.8 mAh g−1 at 0.1 C after 90 cycles with 98% Coulombic efficiency and high rate capability of 515.9 mAh g−1 at 4.5 C, thus exhibiting one of the best lithium storage properties among the reported ZnCo2O4 anodes. The significant enhancement of the electrochemical performance of the nanocomposite anode could be credited to the strong synergy between ZnCo2O4 and graphene nanosheets, which maintain excellent electronic contact and accommodate the large volume changes during the lithiation/delithiation process.

Figure optionsDownload as PowerPoint slide