VO2 nanoflake arrays for supercapacitor and Li-ion battery electrodes : performance enhancement by hydrogen molybdenum bronze as an efficient shell material

• Main Authors: Xia, Xinhui, Chao, Dongliang, Ng, Chin Fan, Lin, Jianyi, Fan, Zhanxi, Zhang, Hua, Shen, Ze Xiang, Fan, Hong Jin
• Other Authors: School of Materials Science & Engineering
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Materials::Biomaterials
• Online Access: https://hdl.handle.net/10356/106651; http://hdl.handle.net/10220/24452
• Institution: Nanyang Technological University

Hydrogen molybdenum bronze (HMB) is electrochemically deposited as a homogeneous shell to VO2 nanoflakes grown on graphene foam (GF), forming a GF+VO2/HMB integrated electrode structure. Asymmetric supercapacitors based on the GF+VO2/HMB cathode and neutral electrolyte are assembled and show enhanced performance with weaker polarization, higher specific capacitance and better cycling life than the unmodified GF+VO2 electrode. Capacitances of 485 F/g (2 A/g) and 306 F/g (32 A/g) are obtained because of the exceptional 3D porous architecture and conductive network. In addition, the GF+VO2/HMB electrodes are also characterized as the cathode of lithium ion batteries. Very stable capacities at rates up to 30 C are demonstrated for 500 cycles. This new type of shell material is expected to have its generic function in other metal oxide based nanostructures.