title: Facile synthesis of hierarchical porous VOx@carbon composites for supercapacitors.
abstract: Hierarchical or micro-nano structured porous VOx@carbon composites were synthesized by a one-step method using phenolic resin as the carbon precursor and ammonium metavanadate as the source of vanadium oxides. The effects of the vanadium source loading on the microstructure and electrochemical properties of the composites were investigated. X-ray diffraction results showed that as the vanadium oxides source loading increased, vanadium oxides in the composites changed oxidation states from V2O3 to mixed states of V2O3 and VO2. Electrochemical test results indicated that the micro-nano porous structure of the composites could facilitate the ion diffusion in the rich porous structure and then promote the electrochemical reaction. More importantly, we found that vanadium oxides greatly enhanced the electrochemical performance of the materials, due to the faradic capacitance generated from vanadium oxide nanoparticles. A maximum specific capacitance of 171 F/g was obtained from VOx@carbon composite with vanadium loading of ∼44 wt%. Further increasing the VOx loading over this fraction was not beneficial. Our results suggested that hierarchical porous VOx@carbon composites were promising candidates for supercapacitor applications.
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Chunxia
authors.initials: C
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Jinqiao
authors.initials: J
authors.lastname: Cao
authors.affiliation: Earth Science and Resource Engineering, CSIRO, VIC 3168, Australia.
authors.forename: Yunxia
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China. Electronic address: chenw@whut.edu.cn.
authors.forename: Wen
authors.initials: W
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Advanced Technology for Materials Synthesis and Progressing, School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
authors.forename: Junshen
authors.initials: J
authors.lastname: Li
keywords: Hierarchical porous structure; Micro–nano structure; One-step synthesis; Supercapacitor; VO(x)@carbon composite