Designing high-capacity cathode materials for sodium-ion batteries

Na-rich layered oxides as cathode materials for sodium-ion batteries were designed using an electrochemical method based on Li-rich layered oxides. The materials show high specific capacity that can reach 234 mAh/g at a current of 5 mA/g. The energy density of this material (644 Wh/kg) is even higher than those of commercial cathodes for lithium-ion batteries, such as LiFePO4 and LiMn2O4. Kinetic analysis of Na+ insertion/extraction into/from the Na-rich layered oxide reveals that the Na+ diffusion coefficient is about 10(-14) cm(2)/s. (C) 2013 Elsevier B.V. All rights reserved.