Holey Aligned Electrospun Carbon Electrodes for High-Performance Redox Flow Batteries

摘要

Recently, the electrospinning method has been employed to fabricate fibrous carbon electrodes in redox flow batteries, due to the large specific surface area of the nano-scale electrospun carbon fibers. However, the poor transport properties of the densely packed electrospun carbon electrodes cause a large flow resistance, and hence a large concentration overpotential, which limited the battery's performances. The vanadium redox flow battery (VRFB) is one of the most-studied redox flow battery systems. However, the state-of-art VRFB that employed electrospun carbon fibers as the electrode can only be operated a realtively small current density (～100 mA cm~(-2)), which is mainly hindered by the poor transport properties of the electrode material. Hence, the geometric structures of the electrospun carbon materials should be tailored so that the battery with the electrospun carbon fibers can be operated at a much elevated current density with high energy efficiency. Currently, several strategies have been proposed to improve the transport properties of the electrospun material, which include increasing the fiber diameter and expanding the pore sizes. However, the enhancement in the transport properties is always at the cost of sacrificing the active surface area.