One-step fabrication of in situ carbon-coated NiCo2O4@C bilayered hybrid nanostructural arrays as free-standing anode for high-performance lithium-ion batteries

Rapid developments in revolutionary electric vehicles have led to an increase in the energy-density and cycling-life requirements for Li-ion batteries (LIBs). The binary transition metal oxide NiCo2O4 is attracting considerable attention due to its much larger specific capacity than graphite. However, NiCo2O4 suffers from poor cycling performance owing to a large volume change during cycling. To address this problem, we proposed an easy strategy to fabricate in situ carbon-coated NiCo2O4 bilayered hybrid nanostructural arrays supported on Ni foam (denoted as NiCo2O4@C BHNAs-NF) as free-standing anodes for LIBs through a sucrose-assisted hydrothermal method. The in situ-synthesized uniform carbon shell can simultaneously buffer the volume change during cycling and increase the conductivity. The micro/nano-structure also possessed outstanding structural advantages, such as large surface area and hierarchical porous characters, enabling NiCo2O4@C BHNAs-NF to have excellent electrochemical performance. Its capacity can reach 1298 mAh/g at a current density of 100 mA/g, and 86% of the initial capacity can be retained after 100 cycles. All these results revealed that NiCo2O4@C BHNAs-NF was a promising candidate anode for next-generation LIBs.