材料科学
电化学
锂(药物)
阴极
化学工程
过渡金属
透射电子显微镜
循环伏安法
锰
钴
容量损失
纳米技术
冶金
电极
化学
物理化学
医学
工程类
内分泌学
催化作用
生物化学
作者
Zhengyu Cai,Shuai Wang,Hecheng Zhu,Xi Tang,Yanhang Ma,Denis Y. W. Yu,Shihong Zhang,Guowen Song,Weidong Yang,Yang Xu,Wen Chen
标识
DOI:10.1016/j.jcis.2022.10.105
摘要
Layered oxides based on manganese (Mn), rich in lithium (Li), and free of cobalt (Co) are the most promising cathode candidates used for lithium-ion batteries due to their high capacity, high voltage and low cost. These types of material can be written as xLi2MnO3·(1 - x) LiTMO2 (TM = Ni,Mn,etc.). Though, Li2MnO3 is known to have poor cycling stability and low capacity, which hinder its industrial application commercially. In this work, Li1.2Ni0.2Mn0.6O2 materials with different amounts of structural defects was successfully synthesized using powder metallurgy followed by different cooling processes in order to improve its electrochemical properties. Microstructural analyses and electrochemical measurements were carried out on the study samples synthesized by a combination of X-ray diffraction, transmission electron microscopy, and cyclic voltammetry. It is found that the disorder of the transition metal layer in Li2MnO3 promotes its electrochemical activity, whereas the Li/Ni antisites of the Li layer maintain the stability of its local structure. The material with optimal amount of structural defects had an initial capacity of 188.2 mAh g-1, while maintaining an excellent specific capacity of 144.2 mAh g-1 after 500 cycles at 1C. In comparison, Li1.2Ni0.2Mn0.6O2 without structural defect only gives a capacity of 40.8 mAh g-1 after cycling. This microstructural control strategy provides a simple and effective route to develop high-performance Co-free, Li-rich Mn-based cathode materials and scale-up manufacturing.
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