石墨
微晶
制作
氟
阳极
兴奋剂
材料科学
离子
氢氟酸
化学工程
冶金
电极
化学
光电子学
有机化学
工程类
结晶学
病理
物理化学
医学
替代医学
作者
Yun Zhao,Linan Yang,Canliang Ma,Gaoyi Han
出处
期刊:Energy & Fuels
[American Chemical Society]
日期:2020-06-09
卷期号:34 (7): 8993-9001
被引量:31
标识
DOI:10.1021/acs.energyfuels.0c01608
摘要
Graphite has been considered as a promising anode material of potassium-ion batteries (KIBs), the practical applications of which are impeded because of the unsatisfactory cycling stability and poor rate capability. In this study, the favorable effect of fluorine-doping on the K-storage performance of graphite is demonstrated. For a more practical application, a low-grade microcrystalline graphite (MG) ore is chosen as the raw material and is purified through a facile hydrofluoric acid solution immersion method. The results indicate that the mild purification process not only results in a high purity of 98.59 wt % for MG but also realizes the effective F-corporation in the graphite host. The fluorine content of 1.02% with a high semi-ionic bond constituent (70.53%) enlarges the graphite interlayer distance from 3.356 to 3.461 Å, which contributes to an alleviated volume change and faster K-ion diffusion kinetics. Benefiting from the F-doping-induced structural improvement, the modified MG electrode exhibits a prominently elevated reversible capacity (320 mA h g–1), a superior cycling ability with a high capacity retention of 74.6% after 100 cycles, and an enhanced rate performance. This study manifests that F-doping is a feasible route to resolve the obstacles of graphite materials and paves the way for commercial KIBs with high performance.
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