Rapid-rate Capability of Micro-/Nano-Structured CoO Anodes with Different Morphologies for Lithium-ion Batteries

In this study, special micro-/nano-structured CoO powders with different morphologies (cube, sphere and spindle) have been synthesized successfully. All of micro-scale particles (cube, 1.0-4.0 mu m in edge length; sphere, 3.0-7.0 mu m in diameter; spindle, 2.0-5.0 mu m in length and 1.0-3.0 mu m in width) are built up by irregular nano-scale components (10-200 nm) attached to each other. Their specific surface areas are about 4.99 m(2)g(-1), 5.01 m(2)g(-1) and 15.74 m(2)g(-1), and their average pore sizes are about 1.89 nm, 1.63 nm and 1.88 nm, respectively. By evaluation with electrochemical measurements, all of them possess high initial discharge capacities (1194.4 mAhg(-1), 1208.5 mAhg(-1) and 1248.7 mAhg(-1) at 0.8 Ag-1), among which the spindle CoO electrode exhibits the best rapid-rate capability (the discharge capacity retention ratios at 0.8 Ag-1 after 50 cycles and at 1.6 Ag-1 after 30 cycles are 87.3% and 77.7%).