Titanium‐Substituted Tavorite LiFeSO4F as Cathode Material for Lithium Ion Batteries: First‐Principles Calculations and Experimental Study. Issue 5 (11th May 2020)

• Record Type: Journal Article
• Authors: Guo, Zhendong; Wang, Dashuai; Zhang, Lijie; Fu, Qiang; Wei, Yingjin
• Is Part Of: ChemPlusChem. Volume 85:Issue 5(2020)
• Page Start: 900
• Page End: 905
• Publication Date: 2020-05-11
• Subjects: cathode materials -- electrochemistry -- lithium-ion batteries -- tavorite LiFeSO4F -- titanium; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.202000301
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: Titanium‐substituted LiTi x Fe1−2 x SO4 F ( x =0, 0.01, 0.02, 0.03) cathode materials were synthesized by a solvothermal method. X‐ray diffraction, X‐ray photoelectron spectroscopy, and Mössbauer spectroscopy were used to investigate the effects of Ti substitution on the structure of LiFeSO4 F, and it was shown that Ti substitutes the Fe(2) site. First‐principles calculations and UV‐visible spectroscopy demonstrate that Ti substitution reduces the bandgap of LiFeSO4 F which improves the electronic conductivity from 8.3×10 −12 S cm −1 to 3.9×10 −11 S cm −1 . CI‐NEB and BV calculations show that the Li diffusion energy barriers along the (100), (010) and (101) directions are decreased after Ti substitution, and the Li diffusion coefficient is increased from 4.99×10 −11 cm 2 S −1 to 1.59×10 −10 cm 2 S −1 . The improved electronic conductivity and ionic diffusivity mean that the Ti‐substituted material shows improved electrochemical properties compared to the pristine LiFeSO4 F. Abstract : Heterovalent ionic Ti 4+ can substitute the Fe(2) site of LiFeSO4 F. Ti substitution reduced the bandgap of the host material, which improved the electronic conductivity, and first‐principles calculations showed the Li diffusion energy barriers were reduced after Ti substitution, thus improving the Li diffusion coefficient. As a result, Ti‐substituted LiTi x Fe1−2 x SO4 F exhibited outstanding electrochemical properties.