Improved electrochemical performances of LiOVPO4/ketjen black composite prepared by a novel solvent-thermal oxidation route

• Published in: Ionics 2021, Vol.27 (7), p.2937-2943
• Main Authors: Tang, Anping, Chen, Juedong, Fu, Yangyang, Chen, Hezhang, Xu, Guorong, Song, Haishen, Peng, Ronghua, Yi, Qingfeng
• Format: Article
• Language: English
• Subjects: Chemical synthesis; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Cycles; Discharge; Electrochemistry; Energy Storage; Heat treatment; Optical and Electronic Materials; Original Paper; Oxidation; Precursors; Renewable and Green Energy; Solvents; Vanadium oxides
• ISSN: 0947-7047; 1862-0760
• DOI: 10.1007/s11581-021-04053-6

Orthorhombic β-LiVOPO 4 /ketjen black composite is obtained via a two-step chemical synthesis. In the first step, Li 3 V 2 (PO 4 ) 3 -V 2 O 3 /ketjen black precursor is obtained by spray-drying process and subsequent heat treatment. Solvent-thermal oxidation of the precursor results in the complete formation of β-LiVOPO 4 /ketjen black composite. The synthesized composite is characterized by means of X-ray diffraction, scanning electron microscopy, nitrogen sorption, and electrochemical tests. Galvanostatic charge–discharge cycling of the composite shows an initial discharge specific capacity of 305, 289, 276, 242, 157, and 77 mAh·g −1 at C/20, C/10, C/5, C/2, 1C, and 2C rate in a voltage window of 2.0–4.5 V, respectively. At higher current rates, although it exhibits good retention of discharge capacity, the capacity is found to reduce with increasing current rates. The composite displays excellent cycling performance at a current rate of C/5 up to 50 cycles, which yields a high specific capacity of 245 mAh·g −1 at the end of the 50th cycle and a small capacity fading of 0.13% per cycle.