Black defect-engineered TiO2 nanocrystals fabricated through square-wave alternating voltage as high-performance anode materials for lithium-ion batteries

Black defect-engineered TiO2 nanocrystals have been successfully fabricated via electrochemical square-wave alternating voltage method. Repeated redox of Ti foil surface accompanying vigorous hydrogen evolution plays a key role on the formation of the black TiO2 nanocrystals. Transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller specific surface area are utilized to characterize the structure and properties of the products. When utilized as anode materials for lithium-ion batteries, the black TiO2 nanocrystals electrode exhibits a high reversible capacity of 271 and 266 mAh g(-1) after 200 cycles at 0.5 C (1 C = 168 mA g(-1)), as well as a good rate capability, which are likely to be associated with small particle size (ca. 6 nm), surface/interfacial pseudocapacitive lithium storage and increased electronic conductivity contributed from Ti3+ defects. (C) 2018 Elsevier B.V. All rights reserved.