title: ZrO2-Nanoparticle-Modified Graphite Felt: Bifunctional Effects on Vanadium Flow Batteries.
abstract: To improve the electrochemical performance of graphite felt (GF) electrodes in vanadium flow batteries (VFBs), we synthesize a series of ZrO2-modified GF (ZrO2/GF) electrodes with varying ZrO2 contents via a facile immersion-precipitation approach. It is found that the uniform immobilization of ZrO2 nanoparticles on the GF not only significantly promotes the accessibility of vanadium electrolyte, but also provides more active sites for the redox reactions, thereby resulting in better electrochemical activity and reversibility toward the VO(2+)/VO2(+) and V(2+)/V(3+) redox reactions as compared with those of GF. In particular, The ZrO2/GF composite with 0.3 wt % ZrO2 displays the best electrochemical performance with voltage and energy efficiencies of 71.9% and 67.4%, respectively, which are much higher than those of 57.3% and 53.8% as obtained from the GF electrode at 200 mA cm(-2). The cycle life tests demonstrate that the ZrO2/GF electrodes exhibit outstanding stability. The ZrO2/GF-based VFB battery shows negligible activity decay after 200 cycles.
authors.affiliation: Institute of Green Chemistry and Energy, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China.|Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Haipeng
authors.initials: H
authors.lastname: Zhou
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology , Guangzhou 510640, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Institute of Green Chemistry and Energy, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China.
authors.forename: Jingyu
authors.initials: J
authors.lastname: Xi
authors.affiliation: Institute of Green Chemistry and Energy, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China.|Key Lab of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Xinping
authors.initials: X
authors.lastname: Qiu
authors.affiliation: Institute of Green Chemistry and Energy, Graduate School at Shenzhen, Tsinghua University , Shenzhen 518055, China.|Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences , Beijing 100084, China.
authors.forename: Liquan
authors.initials: L
authors.lastname: Chen
keywords: ZrO2; electrocatalyst; electrolyte accessibility; graphite felt; vanadium flow battery