A High-Performance Li2FeSiO4/C Cathode Enhanced by a Novel Liquid-State Carbon Source

作者：Qu, Long^*; Li, Mingtao; Liu, Pei; Tian, Xiaolu; Yi, Yikun; Yang, Bolun

来源：International Journal of Electrochemical Science, 2018, 13(12): 12311-12319.

DOI：10.20964/2018.12.43

• Lithium-ion battery
• Polyanion-type compound
• Cathode materials
• Lithium iron silicate
• Liquid carbon source
• Carbon coating

A novel liquid-state carbon source, [2-[(2R, 3S, 4R)-3,4-dihydroxytetrahydrofuran-2-yl]-2-hydroxyethyl] dodecanoate (sorbitan monolaurat, Span-20, C18H34O6), is used to synthesize Li2FeSiO4/C by the sol-gel method. X-ray diffraction and scanning electron microscope measurements are carried out to determine the crystal structures, morphologies and particle sizes of the resulting products. The results show that Li2FeSiO4/C has pure phase and the average particle size of Li2FeSiO4 is in 20-30 nm. The result of Raman spectroscopy measurement indicates that the liquid-state carbon source can be prone to generate the carbon materials with high-ordered structure compared to the solid-state carbon source. The Li2FeSiO4/C cathode delivers an initial discharge capacity of 187 mAh g(-1) at 0.1 C rate, and it also shows good rate performance and stable cycle performance, indicating that the liquid-state carbon source helps to improve the electrochemical performance of the Li2FeSiO4/C cathode. By analyzing electrochemical impedance spectra, it is concluded that the carbon coating layer generated from the liquid-state Span-20 enhances the electrode/electrolyte interface characterization and improves the Li+ diffusion.

• 出版日期2018-12
• 单位西安交通大学