Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7724920 | Journal of Power Sources | 2018 | 9 Pages |
Abstract
A series of layered Na0.67Lix(Ni0.2Fe0.15Mn0.65)1-xO2+δ (xâ¯=â¯0, 0.1, 0.2 and 0.3) compounds is prepared via a facile oxalate coprecipitation method and a solid-state reaction process, and investigated as the promising positive electrode materials for Na-ion batteries. As the Li content increases, O3 phase and Li2MnO3 gradually grow at the expense of the P2 phase and the particles become smaller and more agglomerated based on X-ray diffraction, scanning electron microscopy and transmission electron microscope results. The optimal Na0.67Li0.2(Ni0.2Fe0.15Mn0.65)0.8O2+δ shows the improved electrochemical performance with a high specific capacity of 151â¯mAh gâ1 and 78% capacity retention over 50 cycles at 0.1â¯C (15â¯mAâ¯gâ1). When tested at 5â¯C (750â¯mAâ¯gâ1) rate, the electrode exhibits a discharge capacity of 68â¯mAh gâ1. The results of electrochemical impedance spectroscopic and ex-situ X-ray diffraction measurements demonstrate that the improved cyclability and rate capability of the Li-substituted cathode can be ascribed to the decreased resistance and the enhanced structure stability in the high voltage of 4.3â¯V.
Keywords
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Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Yong Wang, Guorong Hu, Zhongdong Peng, Yanbing Cao, Xiangwan Lai, Xianyue Qi, Zhanggen Gan, Wei Li, Zhongyuan Luo, Ke Du,