Systematic investigation on determining chemical diffusion coefficients of lithium ion in Li1+x VPO4F (0 aparts per thousandcurrency signaEuroparts per thousandx aparts per thousandcurrency signaEuroparts per thousand2)

作者：Wang, Jiexi; Li, Xinhai^*; Wang, Zhixing; Guo, Huajun; Huang, Bin; Wang, Zhiguo; Yan, Guochun

来源：Journal of Solid State Electrochemistry, 2015, 19(1): 153-160.

DOI：10.1007/s10008-014-2586-9

• Chemical diffusion coefficient
• Electrochemical impedance spectroscopy
• Cyclic voltammetry
• Galvanostatic intermittent titration technique
• Lithium vanadium fluorophosphate

The chemical diffusion coefficients of lithium ion () in Li1 + x VPO4F (0 a parts per thousand currency signaEuro parts per thousand x a parts per thousand currency signaEuro parts per thousand 2) between 3.0 and 0.01 V are systematically analyzed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic intermittent titration technique (GITT). The results indicate that the values depend heavily on the voltage state. Based on the results from EIS and GITT, the diffusion coefficients () measured in a single-phase region below 1.7 V have relatively steady values of about 10(-9) (EIS) and 10(-10) (GITT) cm(2) s(-1), respectively, while the values in the single-phase region above 1.9 V decrease rapidly from 10(-9) to 10(-11) cm(2) s(-1) due to concentration of lithium ions in the bulk LiVPO4F. The Li+ chemical diffusion coefficients measured in the two-phase region by GITT range a lot from 10(-9) to 10(-14) cm(2) s(-1), while the values in the two-phase region determined by CV are around 10(-10) cm(2) s(-1). By the GITT, the values in the two-phase region vary in non-linear shape with the charge-discharge voltage, which is ascribed to strong interactions of Li+ with other ions.

• 出版日期2015-1
• 单位中南大学