材料期刊网

采用溶胶-凝胶法制备Li-Ni-Co-Mn-O化合物的前驱体. 借助于X射线衍 射(XRD)、扫描电镜(SEM)及充、放电测试等表征了不同温度下焙烧前驱体对高 温合成的Li-Ni-Co-Mn--O固溶体晶体结构、形貌及电化学性能的影响. 结果表明: 前驱体于600℃焙烧即可形成六方层状结构的Li-Ni-Co-Mn-O固溶体, 920-980 ℃ 产物的衍射峰强度及颗粒尺寸随合成温度的升高而增大, 950 ℃合成产物的 I_003 / I 104及晶胞体积要比920和980 ℃合成产物的大, 而且950 ℃合成产物 的首次充、放电容量最高, 电极极化最小, 在2.5-4.5 V以28 mA/g的电流密度进行 恒流充、放电, 其放电比容量达180 mA•h/g, 循环稳定性较好.

The cathode material for lithium batteries Li1.15-xNi1/3Co1/3Mn1/3O2+δ has been synthesized by sol-gel technique. The effects of synthesizing temperature on the structure, micro-morphology and electrochemical properties of these materials were investigated using X-ray diffraction, scanning electron microscopy and charge-discharge cycling tests. The material synthesized at 600 ℃ has a hexagonal layered structure. The intensity of the diffraction peaks and the particle size of the material synthesized at 920-980 ℃ increased with synthesizing temperature. The ratio values of I_003/I_104 and unit cell volume of the material synthesized at 950 ℃ are larger than those of the material synthesized at 920 and 980 ℃. The maximum charge/discharge capacity and the minimum electrode polarization were obtained for the material synthesized at 950 ℃, which has the initial discharge capacity of 180 mA•h/g in the range of 2.5-4.5 V at a specific current of 28 mA/g.