Dispersion of Li[Ni0.2Li0.2Mn0.6]O2Powder by Surfactant for High-power Li-ion Cell

Abstract

The particle size of Li[<TEX>$Ni_{0.2}Li_{0.2}Mn_{0.6}]O_2$</TEX> cathode powder was controlled effectively by dispersion using lauric acid as a surfactant. The samples treated by lauric acid showed smaller particles of approximately half the original size compared to the particles of a pristine sample. A structural change due to the dispersion of Li[<TEX>$Ni_{0.2}Li_{0.2}Mn_{0.6}]O_2$</TEX> powder was not detected. The rate performance of the Li[<TEX>$Ni_{0.2}Li_{0.2}Mn_{0.6}]O_2$</TEX> cathode was improved by dispersion using lauric acid, which was likely due to the decrease of the particle size. In particular, a sample dispersed pristine powder using lauric acid (L2) presented a greatly enhanced discharge capacity and capacity retention at a high C rate. The discharge capacity of a pristine sample was only 133 m<TEX>$Ahg^{-1}$</TEX> (3C rate) and 96 m<TEX>$Ahg^{-1}$</TEX> (12C rate) at the tenth cycle. In contrast, the L2 electrode delivered higher discharge capacities of 160 m<TEX>$Ahg^{-1}$</TEX> (3C rate) and 129 m<TEX>$Ahg^{-1}$</TEX> (12C rate) at the tenth cycle. The capacity retention at a rate of 12C/2C was also enhanced from ~ 45% (pristine sample) to 57% (L2) by treatment with lauric acid.