Synergistic Catalysis of SnO(2)-CNTs Composite for [Formula: see text] /VO(2+) and V(2+)/V(3+) Redox Reactions

In this study, a SnO(2)-carbon nanotube (SnO(2)-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 [Formula: see text] /VO(2+), and on the V(2+)/V(3+) redox reactions and VRFB performance were investigated. The SnO(2)-CNT composite has better catalytic activity than pure SnO(2) and CNT due to the synergistic catalysis of SnO(2) and the CNT. SnO(2) mainly provides the catalytic active sites and the CNTs mainly provide the three-dimensional structure and high electrical conductivity. Therefore, the SnO(2)-CNT composite has a larger specific surface area and an excellent synergistic catalytic performance. For cell performance, it was found that the SnO(2)-CNT cell shows a greater discharge capacity and energy efficiency. In particular, at 150 mA cm(−2), the discharge capacity of the SnO(2)-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(2)-CNT is an efficient and promising catalyst for VRFB.