An advanced integrated electrode with micron- and nano-scale structures for vanadium redox flow battery

Improving battery performance and cycle life is an effective way to increase the share of vanadium redox flow batteries (VRFBs) in the energy storage market. Here, an advanced integrated electrode with micron- and nano-scale structures is fabricated through multi-step electrospinning and post-functionalization processes. For micron-scale structure, the reaction region and the electron transport region are constructed to optimize activation areas and electron conduction process. For nano-scale structure, the catalytic layer with oxygen-rich gradient nanopores and the conductive layer with electron transport channels are generated to enhance electrocatalytic and conductive performances without sacrificing mass transport. The VRFB with the as-prepared electrodes achieves an outstanding performance with 80.28% energy efficiency at 250 mA cm−2 and is stably cycled for more than 1000 cycles. Besides, it delivers a high peak power density of 702.98 mW cm−2, which is 69.45% higher than that of the battery with conventional graphite felts. More importantly, the rationality of structure design is verified, and different application ways of the as-prepared electrodes are compared. This work provides an inspiration in structural design for the development of high performance electrodes for VRFBs.