Enhanced Electrochemical Properties of Sn-doped V2O5 as a Cathode Material for Lithium Ion Batteries. (20th December 2016)

• Record Type: Journal Article
• Authors: Li, Zhuoyu; Zhang, Changkun; Liu, Chaofeng; Fu, Haoyu; Nan, Xihui; Wang, Kan; Li, Xinyuan; Ma, Wenda; Lu, Xianmao; Cao, Guozhong
• Is Part Of: Electrochimica acta. Volume 222(2016)
• Page Start: 1831
• Page End: 1838
• Publication Date: 2016-12-20
• Subjects: V2O5 -- Sn-doping -- Oxygen vacancies -- Cathode -- Lithium ion batteries; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2016.11.174
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: Highlights: A series of Sn-doped V2 O5 were systematically studied as cathodes for LIBs. Sn dopant led to a continuous lattice expansion in host V2 O5 . Oxygen vacancies provided active sites to enhance specific capacities. Expanded lattice accelerated the ion diffusion for improving the rate capabilities. Abstract: Cation doping of lithium ion batteries (LIBs) cathode materials is beneficial to both ion-diffusion and charge transfer in the electrochemical intercalation processes and hence may improve battery rate capability. In the present study, a series of Sn-doped V2 O5 microspheres were prepared for LIBs cathode via a microwave-assisted solvothermal synthesis. X-ray diffraction analysis suggests that Sn 4+ ions with an ionic radius 22% larger than that of V 5+ successfully entered into the crystal lattice and led to lattice expansion of V2 O5 . The doping of Sn 4+ also induced the formation of oxygen vacancies that would allow more active sites for the intercalation/extraction reactions of Li + ions. Compared with pristine V2 O5, Sn-doped samples demonstrated both improved capacity and rate capability. Particularly, V2 O5 doped with 4% Sn 4+ (denoted as Sn0.04 V1.96 O5- δ ) delivered a high reversible specific capacity of 292 mAh g −1 in the voltage window of 2.0–4.0 V ( vs . Li/Li + ) at a current density of 50 mA g −1 . Much enhanced rate performance was also attained for the doped samples (220.4 mAh g −1 at 500 mA g −1 and 162.5 mAh g −1 at 2, 000 mA g −1 for Sn0.04 V1.96 O5- δ ) compared to V2 O5 (148.6 mAh g −1 at 500 mA g −1 and 72.3 mAh g −1 at 2, 000 mA g −1 ). The improved electrochemical properties of Sn-doped V2 O5 can be attributed primarily to the lattice expansion upon doping that led to higher lithium diffusion coefficient (4.45 × 10 −11 cm 2 s −1 ) than V2 O5 (2.84 × 10 −11 cm 2 s −1 ) as well as the presence of rich oxygen vacancies.