Electrochimica Acta, Vol.298, 640-649, 2019
Preparation of oxygen-deficient WO3-x nanosheets and their characterization as anode materials for high-performance Li-ion batteries
To address the large structural and volume changes of commercial WO3 during charge/discharge, which make this material unsuitable for use in Li-ion batteries (LIBs), we herein prepared oxygen deficient WO3-x nanosheets on a large scale by thermal treatment of ammonium paratungstate in a reducing atmosphere followed by sonication and freeze-drying. The above nanosheets were employed as LIB anode materials and exhibited a specific capacity and cycling stability significantly exceeding those of oxygen-deficient WO3-x nanoparticles and commercial WO3. In addition, we investigated the effect of nanosheet loading on electrode performance, demonstrating that the best results (Li storage capacity of similar to 628 mAh g(-1) after 100 cycles at 100 mA g(-1)) were obtained at a nanosheet content of 20 wt%. This excellent performance was ascribe to the good exposure of defects caused by the comparatively small size of WO3-x nanosheets, which resulted in an increased number of sites and diffusion paths available for Li-ion storage and transfer. The novel electrode-optimized strategy may be extended to the fabrication of other electrodes that use nanomaterials as active substances due to its superior comprehensive performance and low cost. (C) 2019 Elsevier Ltd. All rights reserved.