In-Situ Synthesis of 3D Carbon Coated Zinc-Cobalt Bimetallic Oxide Networks as Anode in Lithium-Ion Batteries

Graphical Boosting the network : A 3D porous electrode as anode in lithium-ion batteries is formed, consisting of ZnO-CoO nanoparticles dispersed in a carbon network. The electrode exhibits high specific capacity, superior rate capability, and enhanced cycling stability. The improved electrochemical performance is attributed to the synergistic effect between the active bimetallic oxide and the in-situ coating of the carbon matrix. For applications in lithium-ion batteries, carbon based materials possess high conductivity, whereas transition metal oxides usually show high theoretical lithium ion storage capabilities. Therefore, engineering transition metal oxides into three-dimensional (3D) carbon networks as anodes is expected to achieve long cycling life and excellent rate performance. Here, we report a facile and environmental friendly method for the in-situ synthesis of 3D carbon coated bimetallic oxides with porous network structure. The carbon matrix originates from citric acid, which can be used as food additive. Benefiting from the synergistic effects between ultrafine metal oxides and the conductive carbon layers, the as-synthesized ZnO-CoO nanoparticles dispersed in the porous carbon network (ZnO-CoO@C) exhibit faster lithium diffusion kinetics and significantly improved specific capacity at various current densities and extended cycling life (503 mAh g −1 after 700 cycles at 2000 mA g −1 ). Full-cell assemblies using ZnO-CoO@C as anode and the commercially available material NCM523 as cathode, display a high charging capacity of 94 mAh g −1 after 100 cycles at 100 mA g −1 . The simple and cost-effective synthesis strategy could be motivating for the large-scale manufacture of other in-situ carbon coated bimetallic oxides electrodes for promising energy storage devices.