【作者】 李国华； 李莉萍； 范建明； 李广社；

【Author】 Guohua Li;Liping Li;Jianming Fan;Guangshe Li;Fujian institute of research in structure of matter,Chinese Academy of Sciences;State key laboratory of inorganic synthesis and preparative chemistry,Institute of Chemistry,Jilin University;

【机构】 中国科学院福建物质结构研究所； 无机合成与制备化学国家重点实验室化学学院吉林大学；

【摘要】 层状氧化物LiNi_xCo_1-2xMn_xO₂具有容量高,热稳定性好等优点,被认为是下一代先进能源材料的候选者。但仍存在一些共性的基础问题还末完全清楚,如表面偏析,及电导率。在实际使用中,这些属性对材料的电化学性能有着重大的影响。因此急切需要揭示本体材料的真相。我们分别采用软XPS深度剖析方法和交流阻抗法研究了这类层状氧化物的表面偏析现象、规律及其电学行为。结果表明这类氧化物具有表面偏析行为:组分Ni和Mn趋于在样品的表面富集;而对于组分Co则具有反偏析的行为;并且它们的相对偏析量是随组分Ni的含量增加而减少的,表现出了组分协同效应。对其体相电导率的研究得到:体相的活化能与锂层厚度有着密切的联系,体相活化能随锂层厚度减少而增加。这项研究可以为我们选择材料和设计材料提供思路。更多还原

【Abstract】 The family of LiNi_xCo_1-2xMn_xO₂ is considered as a candidate for next general advance energy materials with high capacity and excellent thermal ability. However, some mutual science problems of these compounds are not real clearly, such as surface segregation and conductivity. In practical application, these attributions have a remark effect on the electrochemical performance. Hence, it is very urge to reveal the true of pristine material. The soft XPS depth profiling and AC impedance spectrum were carried out to investigate surface segregation behavior and bulk conductivity. The results show that the composition Ni and Mn tend to enrich at the surface region; For Co, it have a anti-segregation behavior. Relative segregation is decrease with the content of Ni increase and the behaviors exhibit composition synergy effect. The activity energy of bulk is close relation with the LiO₂ slab and increase with the slab deduce. The study can provide some minds for us to choose materials and design new materials.更多还原