We report the high capacity, superior rate capability, and excellent cyclic stability of graphene nanosheets (GNs) decorated with Co 3O 4 nanoparticles as anodes in Li-ion batteries. A pulse microwave-assisted (MA) polyol method (total period: 30 min) is adopted to deposit cobalt oxides onto the GNs in water and ethylene glycol (EG), forming two types of Co 3O 4@GN hybrids. The selection of solvent in the MA process plays a central role in affecting the crystallinity, dispersion, and particle size of cobalt oxide particles. The resulting Co 3O 4@GN hybrid, prepared by the MA method in EG, shows a homogeneous dispersion of Co 3O 4 nanocrystals with an average size of 10 nm. The Co 3O 4@GN hybrid displays advantages of high reversible capacity, excellent cycleability, and high rate capability. This improved cyclic performance can be attributed to the formation of a three-dimensional GN framework decorated with Co 3O 4 nanocrystals, leading to fast diffusion of Li ions (diffusion coefficient: 5.82 × 10 -12 cm 2 s -1) and low internal resistance (equivalent series resistance: 92.2 Ω) determined by electrochemical impedance spectroscopy. With its ease of MA fabrication and good performance, the Co 3O 4@GN hybrid will hold promise in practical Li-ion batteries.
|Number of pages||8|
|Journal||Journal of Physical Chemistry C|
|Publication status||Published - 2012 Jul 26|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films