title: Black Anatase Titania with Ultrafast Sodium-Storage Performances Stimulated by Oxygen Vacancies.
abstract: Nanostructured black anatase titania with oxygen vacancies (OVs) is efficiently obtained and employed as an anode in sodium-ion batteries (SIBs) for the first time. The incorporation of OVs into TiO2 is demonstrated to render considerably enhanced-rate performances, higher initial capacities, and an accelerated electrochemical activation process during cycling, derived from the boosted intrinsic electric conductivity and improved kinetics of Na uptake. Bestowed with the integrated merits of OVs and shortened Na ion diffusion length in the nanostructure, black titania delivers a reversible specific capacity of 207.6 mAh g(-1) at 0.2 C, retains 99.1% over 500 cycles at 1 C stably, and still maintains 91.2 mAh g(-1) even at the high rate of 20 C. Density functional theory (DFT) calculations suggest that the lower sodiation energy barrier of anatase with OVs enables a more favorable Na intercalation into black anatase. Thus, it is of great significance to introduce OVs into TiO2 to stimulate ultrafast and durable sodium-storage properties, which also offers a potential strategy to project more superior electrodes, utilizing internal defects.
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Zhiying
authors.initials: Z
authors.lastname: Ding
authors.affiliation: School of Energy Science and Engineering, University of Electronic Science and Technology of China , Chengdu 611731, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Hongshuai
authors.initials: H
authors.lastname: Hou
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Tianjin EV Energies Company Limited , Tianjin 300380, China.
authors.forename: Chiwei
authors.initials: C
authors.lastname: Wang
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Guoqiang
authors.initials: G
authors.lastname: Zou
authors.affiliation: College of Chemistry and Chemical Engineering, Central South University , Changsha 410083, China.
authors.forename: Xiaobo
authors.initials: X
authors.lastname: Ji
keywords: anode; black anatase; oxygen vacancies; rate performances; sodium-ion batteries