期刊
JOURNAL OF POWER SOURCES
卷 486, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.jpowsour.2020.229373
关键词
Potassium-ion batteries; Electrolyte chemistry; Inorganic compound-rich SEI layer; Iron selenide/carbon nanocomposites
资金
- Special Project Fund of Taishan Scholars of Shandong Province [ts201511017]
- Natural Science Foundation of China [21975286]
- Key research and development plan of Shandong province [2018GGX102017]
- Fundamental Research Funds for the Central Universities [19CX05002A, 17CX02039A]
- New Faculty Start-up funding in China University of Petroleum (East China) [YJ201601023]
The enhanced rate capability and cycling performance of FeSe/C nanocomposites are achieved by electrolyte salt and solvent engineering, with the introduction of KFSI-EC/DEC electrolyte significantly boosting the charge transfer, K-ion diffusion, and capacitive behavior of the electrode. Computational studies on molecular orbital energy levels, X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) characterizations reveal a stable solvation structure and inorganic compound-rich solid electrolyte interphase layer.
Metal selenides with good electronic conductivity and high theoretical capacities are regarded as potential anodes for potassium-ion batteries (PIBs). But the large radius and heavy weight of K-ion, and inefficient electrolyte lead to sluggish reaction kinetics and structure collapse of the electrode. Herein, the enhanced rate capability and cycling performance of FeSe/C nanocomposites are achieved by electrolyte salt and solvent engineering. The introduction of KFSI-EC/DEC electrolyte significantly boosts the charge transfer, K-ion diffusion, and capacitive behavior of FeSe/C electrode, which can be attributed to the stable solvation structure and the inorganic compound-rich solid electrolyte interphase layer demonstrated by computational studies on molecular orbital energy levels, X-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HRTEM) characterizations. Consequently, the FeSe/C electrode shows superior rate performance (230 mA h g(-1) at 10 A g(-1)) and stable cycling performance (550 mA h g(-1) at 0.2 A g(-1) over 100 cycles). Additionally, ex-situ X-ray diffraction, HRTEM and XPS characterizations throw light on the reversible conversion reaction mechanism between FeSe and K-ion.
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