Synergistic Effect of Flakes Containing Interconnected Nanoparticles and Conducting Graphene Additive to Qualify ZnMn2O4 as Potential Lithium-Battery Anode

ZnMn2O4 flakes, composed of interconnected nanoparticles were synthesized by using a hydrothermal technique and treated subsequently with nitrogen-doped graphene (NG) to obtain a composite containing graphene sheets decorated with ZnMn2O4 nanoparticles. When explored as a lithium-battery anode, ZnMn2O4/NG exhibits a superior electrochemical performance compared to a pristine ZnMn2O4 anode. Interestingly, the ZnMn2O4/NG composite anode displays a steady-state reversible capacity of 1400 mAhg(-1) at 100 mAg(-1), which is higher than the theoretical capacity and the highest ever capacity achieved so far, with respect to the ZnMn2O4 electrode material. Furthermore, the nanocomposite anode shows a stable capacity of 790 mAhg(-1) up to 1000 cycles and the corresponding coulombic efficiency is 99% at 500 mAg(-1), exhibiting excellent rate capability. The superior electrochemical performance of the ZnMn2O4/NG anode may be ascribed to the multiple synergistic advantages offered by NG, such as enhanced electrode conductivity, maintenance of structural integrity upon cycling, and the effective accommodation of volume changes during charging and discharging. Our results indicate that the synthesized ZnMn2O4/NG nanocomposite anode could be considered as a promising candidate for next-generation high-rate lithium-ion-battery applications.