Cobalt oxide-carbon nanosheet nanoarchitecture as an anode for high-performance lithium-ion battery.

To improve the electrochemical performance of cobalt oxide owing to its inherent poor electrical conductivity and large volume expansion/contraction, Co3O4-carbon nanosheet hybrid nanoarchitectures were synthesized by a facile and scalable chemical process. However, it is still a challenge to control the size of Co3O4 particles down to ∼5 nm. Herein, we created nanosized cobalt oxide anchored 3D arrays of carbon nanosheets by the control of calcination condition. The uniformly dispersed Co3O4 nanocrystals on carbon nanosheets held a diameter down to ∼5 nm. When tested as anode materials for lithium-ion batteries, high lithium storage over 1200 mAh g(-1) is achieved, whereas high rate capability with capacity of about 390 mAh g(-1) at 10 A g(-1) is maintained through nanoscale diffusion distances and interconnected porous structure. After 500 cycles, the cobalt oxide-carbon nansheets hybrid display a reversible capacity of about 970 mAh g(-1) at 1 A g(-1). The synergistic effect between nanosized cobalt oxide and sheetlike interconnected carbon nanosheets lead to the greatly improved specific capacity and the initial Coulombic efficiency of the hybrids.