AUTHOR=Feng Xiaojian , Xue Jing , Zhang Tongxue , Zhang Zixuan , Han Chao , Dai Lei , Wang Ling , He Zhangxing 

TITLE=Synergistic Catalysis of SnO2-CNTs Composite for VO2+/VO2+ and V2+/V3+ Redox Reactions

JOURNAL=Frontiers in Chemistry

VOLUME=9

YEAR=2021

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.671575

DOI=10.3389/fchem.2021.671575

ISSN=2296-2646

ABSTRACT=<p>In this study, a SnO<sub>2</sub>-carbon nanotube (SnO<sub>2</sub>-CNT) composite as a catalyst for vanadium redox flow battery (VRFB) was prepared using a sol-gel method. The effects of this composite on the electrochemical performance of <inline-formula><mml:math id="M2" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msubsup><mml:mrow><mml:mtext>VO</mml:mtext></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msubsup></mml:math></inline-formula>/VO<sup>2+</sup>, and on the V<sup>2+</sup>/V<sup>3+</sup> redox reactions and VRFB performance were investigated. The SnO<sub>2</sub>-CNT composite has better catalytic activity than pure SnO<sub>2</sub> and CNT due to the synergistic catalysis of SnO<sub>2</sub> and the CNT. SnO<sub>2</sub> mainly provides the catalytic active sites and the CNTs mainly provide the three-dimensional structure and high electrical conductivity. Therefore, the SnO<sub>2</sub>-CNT composite has a larger specific surface area and an excellent synergistic catalytic performance. For cell performance, it was found that the SnO<sub>2</sub>-CNT cell shows a greater discharge capacity and energy efficiency. In particular, at 150 mA cm<sup>−2</sup>, the discharge capacity of the SnO<sub>2</sub>-CNT cell is 28.6 mAh higher than that of the pristine cell. The energy efficiency of the modified cell (7%) is 7.2% higher than that of the pristine cell (62.8%). This study shows that the SnO<sub>2</sub>-CNT is an efficient and promising catalyst for VRFB.</p>