Solvent-Controlled Synthesis of NiO-CoO/Carbon Fiber Nanobrushes with Different Densities and Their Excellent Properties for Lithium Ion Storage.

NiO-CoO nanoneedles are grown on carbon fibers by a solvothermal strategy to form nanobrushes. The density of nanobrushes can be easily controlled by altering the solvents. The synthesis mechanism of NiO-CoO/carbon fiber nanobrushes is investigated by the time-dependent experiments in detail. As anodes for lithium ion batteries, the NiO-CoO/carbon fiber nanobrushes synthesized in ethanol show excellent properties with a discharge capacity of 801 mA h g(-1) after 200 cycles at a current density of 200 mA g(-1). The improvement can be ascribed to the carbon fibers as the highway for electrons and the interspace between NiO-CoO nanoneedles to accommodate the volume change and maintain the structural stability.