氧气
电化学
阴极
氧化物
材料科学
化学计量学
氧化还原
相(物质)
锂(药物)
无机化学
化学
电解质
分析化学(期刊)
电极
物理化学
冶金
医学
内分泌学
有机化学
色谱法
作者
Takashi Nakamura,Kento Ohta,Yuta Kimura,Kazuki Tsuruta,Y. Tamenori,Ryotaro Aso,Hideto Yoshida,Koji Amezawa
出处
期刊:ACS applied energy materials
[American Chemical Society]
日期:2020-09-17
卷期号:3 (10): 9703-9713
被引量:22
标识
DOI:10.1021/acsaem.0c01303
摘要
Oxygen defects are closely related to the battery performance of oxide-based cathode active materials for lithium-ion batteries, and especially, positive influences have been reported in Li-rich cathode materials. However, the function of oxygen defects and its influence on electrochemical properties are poorly understood so far. Here, impacts of oxygen vacancy on electrochemical properties of a Li-rich cathode Li1.2Mn0.6Ni0.2O2−δ are reported. Single-phase oxygen-deficient Li1.2Mn0.6Ni0.2O1.97 was prepared by using the solid electrolyte reactor composed of an oxide ion conductor, and its electrochemical properties, crystal, and electronic structures were compared with those of the oxygen-stoichiometric Li1.2Mn0.6Ni0.2O2. In the initial charge, the oxygen-deficient Li1.2Mn0.6Ni0.2O1.97 showed a larger oxidation current due to the oxygen release than the oxygen-stoichiometric Li1.2Mn0.6Ni0.2O2. This suggests that preliminary introduced oxygen vacancy promoted the further oxygen release during the initial charge possibly by accelerating the oxide ion diffusion in the active material via oxygen vacancy. Due to the oxygen release, heavily oxygen-deficient Li1.2Mn0.6Ni0.2O2−δ phase (δ > 0.03) was formed at the near-surface region after the initial charge/discharge cycle. Vigorous Mn redox was observed in the heavily oxygen-deficient Li1.2Mn0.6Ni0.2O2−δ phase during the charge/discharge in contrast to the oxygen-stoichiometric phase wherein Mn was almost inactive for the charge/discharge. The modulation of oxygen defects can be one of effective strategies to control redox species in battery active materials.
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