摘要
使用喷雾干燥法制备了Li1+2xMn0.3+xNi0.3-3xCr0.4O2(x=1/60、1/30、1/20、1/15、1/12)系列样品,并借助XRD,SEM,ICP,XPS,IR和Raman等手段对所制备系列样品的结构、价态及电化学性能进行了表征。研究表明,Li1+2xMn0.3+xNi0.3-3xCr0.4O2系列样品均具有典型的富锂层状固溶体型的晶体结构特征,且在其XRD图谱中未观测到任何杂相的存在。然而,XPS的数据表明Cr3+与Cr6+共存于各个样品中,且由于Cr6+的存在使得样品表现出强烈的吸湿性。Cr6+可通过水洗处理去除。对于它们的电化学特征而言,未经水洗处理的样品由于具有强烈的吸湿性,其电化学性能很差。水洗处理后的系列样品表现出典型的三元富锂层状固溶体的电化学行为,其首次放电比容量随着样品中Li和Mn含量的增加而增大。样品Li1.17Mn0.38Ni0.05Cr0.4O2的首次放电比容量为203 mA h/g,50次循环后容量保持率为71%。
Lithium-rich layered solid solution materials, Li1＋2xMn0.3＋xNi0.3-3xCr0.4O2 （x=l/60, 1/30, 1/20, 1/15, 1/12）, were synthesized by spray-drying process. Their crystal structures, element valences and the electrochemical performances were investigated by XRD, XPS, ICP, SEM, TEM and charge-discharge test. All samples have a typical solid solution feature in terms of their structure, and no impurity phase appears in their XRD profiles. Nevertheless, XPS results suggest that Cr3＋ and Cr6＋ co-exist in all samples. The presence of the Cr^（6＋） in the as-prepared sample results in a high moisture absorption, which can be removed by water washed treatment. As to the electrochemical properties, the as-prepared samples have bad electrochemical performances due to the high moisture absorption. After washing with water, all samples exhibit solid solution behavior, and their initial specific capacities increase as the increase in the amount of Li and Mn. The discharge capacity of Li1.17Mn0.38Ni0.05Cr0.4O2 can reach 203 mAh/gwith a capacity retention of 71% after 50 cycles.
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2013年第6期616-622,共7页
Journal of Inorganic Materials
基金
国家自然科学基金(20973200)~~
关键词
锂离子电池
正极材料
喷雾干燥法
富锂层状固溶体
电化学性质
Li-ion battery
cathode materials
spray-dry
lithium-rich layered solid solution
electrochemicalproperty
