阴极
X射线光电子能谱
电化学
高分辨率透射电子显微镜
介电谱
材料科学
氧化物
相(物质)
透射电子显微镜
扫描电子显微镜
化学工程
分析化学(期刊)
化学
冶金
电极
纳米技术
物理化学
复合材料
有机化学
工程类
作者
Shiming Zhang,Haitao Gu,Tian Tang,Wubing Du,Mingxia Gao,Yongfeng Liu,Dechao Jian,Hongge Pan
标识
DOI:10.1016/j.electacta.2018.01.175
摘要
Li- and Mn-rich layered oxide (LMRO) cathode materials deliver a reversible capacity over 280 mAh g−1, which is almost two times higher than that of traditional cathode materials. However, the improved mechanism of high capacity for the LMRO cathode material has not been elaborated clearly so far. In this work, the relationship between the structures and the electrochemical performance in the Li(2x+2)/(2+x)Ni(2-2x)/(6+3x)Co(2-2x)/(6+3x)Mn(2+4x)/(6+3x)O2 (XLNCMO) (0 ≤ X ≤ 1) cathode materials is systematically studied. Electrochemical performance is evaluated by a galvanostatic charge and discharge test and electrochemical impedance spectroscopy (EIS). Structure and morphology are characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) technologies. Results demonstrate that there is an obvious synergistic effect between the Li2MO3(C2/m) phase and the LiMO2(R-3m) phase in the XLNCMO cathode with a mutual doped composite structure. In this composite structure, the LiMO2(R-3m) phase plays a role of an "activator" to activate the electrochemical activity of the Li2MO3(C2/m) phase and also provides electrochemical capacity, and the Li2MO3(C2/m) phase can be seen as an "stabilizer" to enhance the cycling stability of the LiMO2(R-3m) phase. Moreover, the Li2MO3(C2/m) phase can also be seen as a major contributor for enhancing the electrochemical capacity of the XLNCMO cathodes.
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