The structure, morphology, and electrochemical properties of Li<sub>1+xsub>Ni<sub>1/6sub>Co<sub>1/6sub>Mn<sub>4/6sub>O<sub>2.25+x/2sub> (0.1 鈮?#xa0;x 鈮?#xa0;0.7) cathode materials
摘要
Li<sub>1+xsub>Ni<sub>1/6sub>Co<sub>1/6sub>Mn<sub>4/6sub>O<sub>2.25+x/2sub> (0.1 鈮?#xA0;x 鈮?#xA0;0.7) cathode materials have been synthesized by a simple carbonate co-precipitation method. The effects of the lithium content on the structure, physical property, and electrochemical performance of the samples have been investigated. As the increase of lithium content, the Li<sub>1+xsub>Ni<sub>1/6sub>Co<sub>1/6sub>Mn<sub>4/6sub>O<sub>2.25+x/2sub> evolves from a mixture of hexagonal R鈭?m, monoclinic C2/m, and spinel Fd鈭?m structure to a mixture of hexagonal and monoclinic structure, accompanied with less cation mixing between Li+ and Ni2+. The increase of x value also affects the size of the primary particles and the roughness of the secondary particles. The Li<sub>1+xsub>Ni<sub>1/6sub>Co<sub>1/6sub>Mn<sub>4/6sub>O<sub>2.25+x/2sub> with appropriate lithium content, e.g., x = 0.3, thereby small particle size, high pellet density, and low cation mixing, brings on the largest discharge capacity, which is more than 288 mAh g鈭? in the voltage range of 2.0-4.8 V at 25 mA g鈭?, and the lowest irreversible capacity loss of 47 mAh g鈭? among these cathode materials.