Improved electrochemical performance of bagasse and starch-modified LiNi0.5Mn0.3Co0.2O2 materials for lithium-ion batteries

摘要

Organic carbon-coated LiNi0.5Mn0.3Co0.2O2 materials are prepared by mixing 2 or 5% starch or bagasse evenly with the synthesized LiNi0.5Mn0.3Co0.2O2 material and calcining for 10 h at 750 degrees C. The microstructures and electrochemical performance are investigated by X-ray diffraction, scanning electron microscopy, carbon/sulfur analysis, transmission electron microscopy and electrochemical testing. The results indicate that the organic carbon coated on the surface of LiNi0.5Mn0.3Co0.2O2 material does not change the surface morphology and crystal structure, but greatly improves the conductivity, rate and cycle performance of the LiNi0.5Mn0.3Co0.2O2 cathode in a Li-ion battery. The initial discharge capacity of the synthesized LiNi0.5Mn0.3Co0.2O2 material is 147.8 mAh g(-1), which increases to 152.4 and 153.3 mAh g(-1) for 2% starch and bagasse, respectively. After 100 cycles, the capacity retention rates are 70.7% (uncoated), 83.3% (coated with 2% starch), 90.1% (coated with 2% bagasse), 83.1% (coated with 5% starch) and 91.1% (coated with 5% bagasse). The influence of the percentage of coated carbon and its dispersion uniformity on the performance of the battery is analyzed. A small coating capacity and uniform carbon film can achieve better performance. Rational organic carbon coating technology is an effective way to improve the electrochemical performance of LiNi1-x-yMnxCo O-y(2)-based material.