Synergistic effect of nanofluid as catalyst with carbon foam electrode for improved rheological properties of aqueous electrolytes for vanadium redox flow battery

Enhancing the electrolyte flow characteristics of the electrode is essential in vanadium redox flow batteries. Herein, the design of hybrid electrode with improved flow characteristics is presented to enhance the battery lifetime, electrochemical reaction kinetics, and system efficiency. Further, an open-cell carbon foam is fabricated and experimentally evaluated. This foam acts as a conductor flow field and nanofluidic electrolyte, in which nanoparticles act as a catalyst for electrochemical reactions. The electrochemical performance of a conventional carbon felt electrode is directly compared with that of the hybrid electrode with carbon foam under the same operating conditions. The pumping efficiency of the fabricated hybrid electrode is 1.67 times higher than that of the conventional electrode. The electrochemical reaction is enhanced by the use of nanofluidic electrolytes. Results show that the hybrid electrode with 0.1 wt% nanofluidic electrolyte exhibits the largest discharge capacity (21.85 Wh L−1) and capacity retention (93.4%). The system efficiency can be improved by 2.3% using the hybrid electrodes with nanofluidic electrolytes. This new configuration provides insight into the benefits of replacing conventional carbon felt with carbon foam.