Rational Design of 1-D Co(3)O(4) Nanofibers@Low content Graphene Composite Anode for High Performance Li-Ion Batteries

Cobalt oxide that has high energy density, is the next-generation candidate as the anode material for LIBs. However, the practical use of Co(3)O(4) as anode material has been hindered by limitations, especially, low electrical conductivity and pulverization from large volume change upon cycling. These features lead to hindrance to its electrochemical properties for lithium-ion batteries. To improve electrochemical properties, we synthesized one-dimensional (1-D) Co(3)O(4) nanofibers (NFs) overed with reduced graphene oxide (rGO) sheets by electrostatic self-assembly (Co(3)O(4) NFs@rGO). The flexible graphene oxide sheets not only prevent volume changes of active materials upon cycling as a clamping layer but also provide efficient electrical pathways by three-dimensional (3-D) network architecture. When applied as an anode for LIBs, the Co(3)O(4) NFs@rGO exhibits superior electrochemical performance: (i) high reversible capacity (615 mAh g(−1) and 92% capacity retention after 400 cycles at 4.0 A g(−1)) and (ii) excellent rate capability. Herein, we highlighted that the enhanced conversion reaction of the Co(3)O(4) NFs@rGO is attributed to effective combination of 1-D nanostructure and low content of rGO (~3.5 wt%) in hybrid composite.