材料科学
X射线光电子能谱
阴极
兴奋剂
涂层
极化(电化学)
拉曼光谱
电介质
氧化物
分析化学(期刊)
化学工程
光电子学
纳米技术
化学
冶金
物理
工程类
光学
物理化学
色谱法
作者
Xiaoqian Xu,Yizhen Huang,Dan Li,Qichang Pan,Sun Hu,Yahao Li,Hongqiang Wang,Youguo Huang,Fenghua Zheng,Qingyu Li
标识
DOI:10.1016/j.jechem.2023.03.001
摘要
Charging P2-Na2/3Ni1/3Mn2/3O2 to 4.5 V for higher capacity is enticing. However, it leads to severe capacity fading, ascribing to the lattice oxygen evolution and the P2-O2 phase transformation. Here, the MgFe2O4 coating and Mg, Fe co-doping were constructed simultaneously by Mg, Fe surface treatment to suppress lattice oxygen evolution and P2-O2 phase transformation of P2-Na2/3Ni1/3Mn2/3O2 at deep charging. Through ex-situ X-ray diffraction (XRD) tests, we found that the Mg, Fe bulk co-doping could reduce the repulsion between transition metals and Na+/vacancies ordering, thus inhibiting the P2-O2 phase transition and significantly reducing the irreversible volume change of the material. Meanwhile, the internal electric field formed by the dielectric polarization of MgFe2O4 effectively inhibits the outward migration of oxidized Oα− (α < 2), thereby suppressing the lattice oxygen evolution at deep charging, confirmed by in situ Raman and ex situ XPS techniques. P2-NaNM@MF-3 shows enhanced high-voltage cycling performance with capacity retentions of 84.8% and 81.3% at 0.1 and 1 C after cycles. This work sheds light on regulating the surface chemistry for Na-layered oxide materials to enhance the high-voltage performance of Na-ion batteries.
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