Designing CNT-implanted graphite felt as a sustainable electron network for long-cycling of vanadium redox flow batteries

Carbon nanotubes/Carbon nanofibers (CNT/CNF), owing to their abundant active sites and high acidic resistance, have emerged as promising electrocatalysts for high-energy-density vanadium redox flow batteries (VRFB). However, the utilization of CNT/CNF has been obstructed owing to problems such as cost, and the detachment of CNT/CNF from the carbon electrode caused by the flowing electrolyte in VRFB. In this study, we proposed a novel strategy for uniformly implanted multiwall CNT in electrode materials such as graphite felt, for the development of efficient electron-networked electrodes. The weed root-like morphology of the electrode improved the charge transfer ability and minimized the increase in overpotential even after 1000 cycles of stability test. As a result, the electrode exhibited a high discharge capacity of 30.7 Ah·L−1 and an energy efficiency of 86.9%. Therefore, the proposed CNT implanted electrode can be used as an alternative design in practically feasible VRFB exhibiting sustainable electrochemical performance.