Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (3): 656-664.doi: 10.3866/PKU.WHXB201512292

• ARTICLE • Previous Articles     Next Articles

First-Principles Study on TiO2-B with Oxygen Vacancies as a Negative Material of Rechargeable Lithium-Ion Batteries

Ling-Ming KONG1,Bao-Lin ZHU1,Xian-Yong PANG1,*,Gui-Chang WANG2,3,*   

  1. 1 College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024, P. R. China
    2 Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, P. R. China
    3 State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, P. R. China
  • Received:2015-09-24 Published:2016-03-04
  • Contact: Xian-Yong PANG,Gui-Chang WANG
  • Supported by:
    the State Key Program of Natural Science Foundation of Tianjin, China(13JCZDJC26800);Foundation of State Key Laboratory of Coal Conversion, China(J15-16-908);Natural Science Foundation of Shanxi Province, China(2013011012-8)

Abstract:

Density functional theory calculations were carried out on oxygen-deficient TiO2-B to evaluate the effect of oxygen vacancies on its electrochemical properties. The computational studies focused on the lithium (Li)-ion transport and electronic conductivity of this defect-containing material. Calculations on TiO2-B with low Li-ion concentration (x(Li/Ti)≤ 0.25) suggest that compared with defect-free TiO2-B, oxygen-deficient TiO2-B has a higher intercalation voltage and lower migration activation energy along the b-axis channel. This facilitates Li-ion intercalation, which is beneficial for the charge process of rechargeable batteries. Meanwhile, for TiO2-B with high Li-ion concentration (x(Li/Ti) = 1), saturated oxygen-deficient TiO2-B with lower insertion voltage favors Li-ion deintercalation, which aids the discharge process. Electronic structure calculations suggest that the band gap of this defect-containing material is within 1.0-2.0 eV, which is narrower than that of defect-free TiO2-B (3.0 eV). The main contributor to the band-gap narrowing is the density of the Ti-Ov-3d state, which becomes much higher as the oxygen vacancy content increases, which increases electronic conductivity.

Key words: TiO2-B, Oxygen vacancy, Intercalated voltage, Migration activation energy, Band gap

MSC2000: 

  • O641