材料科学
阴极
堆积
电化学
阳极
化学工程
电极
电容感应
X射线吸收光谱法
氧化物
纳米技术
吸收光谱法
物理化学
化学
操作系统
计算机科学
冶金
有机化学
工程类
物理
量子力学
作者
Yao Xiao,Peng Fei Wang,Ya‐Xia Yin,Yanfang Zhu,Yubin Niu,Xudong Zhang,Jienan Zhang,Xiqian Yu,Xiaodong Guo,Benhe Zhong,Yu‐Guo Guo
标识
DOI:10.1002/adma.201803765
摘要
As one of the most promising cathodes for rechargeable sodium-ion batteries (SIBs), O3-type layered transition metal oxides commonly suffer from inevitably complicated phase transitions and sluggish kinetics. Here, a Na[Li0.05 Ni0.3 Mn0.5 Cu0.1 Mg0.05 ]O2 cathode material with the exposed {010} active facets by multiple-layer oriented stacking nanosheets is presented. Owing to reasonable geometrical structure design and chemical substitution, the electrode delivers outstanding rate performance (71.8 mAh g-1 and 16.9 kW kg-1 at 50C), remarkable cycling stability (91.9% capacity retention after 600 cycles at 5C), and excellent compatibility with hard carbon anode. Based on the combined analyses of cyclic voltammograms, ex situ X-ray absorption spectroscopy, and operando X-ray diffraction, the reaction mechanisms behind the superior electrochemical performance are clearly articulated. Surprisingly, Ni2+ /Ni3+ and Cu2+ /Cu3+ redox couples are simultaneously involved in the charge compensation with a highly reversible O3-P3 phase transition during charge/discharge process and the Na+ storage is governed by a capacitive mechanism via quantitative kinetics analysis. This optimal bifunctional regulation strategy may offer new insights into the rational design of high-performance cathode materials for SIBs.
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