Innovative lithium storage enhancement in cation-deficient anatase via layered oxide hydrothermal transformation. Issue 47 (16th November 2018)

• Record Type: Journal Article
• Authors: Lu, Fengqi; Chen, Qiang; Geng, Shipeng; Allix, Mathieu; Wu, Hui; Huang, Qingzhen; Kuang, Xiaojun
• Is Part Of: Journal of materials chemistry. Volume 6:Issue 47(2018)
• Page Start: 24232
• Page End: 24244
• Publication Date: 2018-11-16
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta07605g
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : An innovative strategy for hydrothermal transformation of layered oxide is presented here to prepare cation-deficient Nb-doped TiO2 anatase and enhance the lithium storage capacity and rate capability of anatase. Abstract : The soft-chemistry synthetic routes of anatase phases for energy conversion and storage usually employ expensive and air-sensitive amorphous alkoxides, which hardly access the electrochemically active cationic vacancy defects in the cationic donor-substituted anatase compositions. Here we demonstrate an innovative way of using layered K3 Ti5 NbO14 as a cost-effectively crystalline precursor to synthesize cation-deficient Nb-doped TiO2 (NTO, formulated as Ti0.8 Nb0.16 □0.04 O2 ) anatase by a one-pot hydrothermal route. When used as an anode in lithium ion batteries, the NTO electrode displayed initial discharge and charge capacities of 618 and 384.6 mA h g −1 at a current density of 0.2C respectively, with a remarkable discharge capacity of ∼246.8 mA h g −1 retained after 100 cycles, representing the highest value among those reported for Nb-doped TiO2 anatases at low current density. A discharge capacity of 137.1 mA h g −1 was obtained even at a high current density of 2C. A full cell, fabricated using the NTO electrode as the anode and a commercial LiCoO2 cathode, is shown to deliver a discharge capacity of 220.2 mA h g −1 after 57 cycles, which exceeds those of most previously reported full cells based on the TiO2 anode and makes this NTO material a promising anode candidate for LIBs. These results present a practical synthetic strategy for tuning cationic vacancies through aliovalent cationic substitution to improve the electrochemical performance of actual LIBs and possibly to develop further relevant devices.