Effects of Na+ contents on electrochemical properties of Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials

• Published in: Journal of power sources Vol. 240; pp. 530 - 535
• Main Authors: Qiu, Bao, Wang, Jun, Xia, Yonggao, Liu, Yuanzhuang, Qin, Laifen, Yao, Xiayin, Liu, Zhaoping
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.10.2013; Elsevier
• Subjects: Applied sciences; Cathode material; Cathodes; Charge; Diffraction; Direct energy conversion and energy accumulation; Discharge; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Layered lithium-excess; Lithium-ion batteries; Materials; Sodium-ions content; Sole; Solid solution; Transforms; X-ray photoelectron spectroscopy; X-rays; Lithium-ion batteries; Cathode material; Layered lithium-excess; Sodium-ions content; Solid solution; Lithium ion batteries; Cathode; Lithium; Secondary cell; Electrode material; Electrochemical properties; Concentration effect; Sodium ion
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.04.047

The Li1.2−xNaxNi0.13Co0.13Mn0.54O2 (0≤x≤0.1) cathode materials have been synthesized by a solid-state reaction method. The effects of the Na+ contents on the structure, surface components and electrochemical performance are studied by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. The XRD data indicate that the Li1.2−xNaxNi0.13Co0.13Mn0.54O2 samples evolve from a sole layered structure (0≤x≤0.02) to a mixture of Na+-contained layered structure (0.02<x≤0.1), which would transform into the single layered structure after the initial charge and discharge process. XPS data demonstrate that some of the Na+ ions could be reversibly de-/re-intercalated for the Li1.2−xNaxNi0.13Co0.13Mn0.54O2 materials. An electrochemical test reveals that a small amount of Na+ (x≤0.02) in the Li1.2−xNaxNi0.13Co0.13Mn0.54O2 materials can significantly increase the rate capacity, yet the capacity retention becomes worse. We also find that the capacity retention increases with the Na+ contents. •A small amount of Na+ can significantly increase the initial discharge capacity.•Some of the Na+ ions could be reversibly de-/re-intercalated from the electrodes.•The structure evolves from a solely layered structure to a mixture of layered structure.•It could explain how the sodium species impact on the electrochemical performance.