Fabricating electrodes with large specific surface area(SSA)and high permeability has been the longstanding target in redox flow batteries(RFBs).In this work,we propose a novel ZIF-8-assisted etching approach to form ...Fabricating electrodes with large specific surface area(SSA)and high permeability has been the longstanding target in redox flow batteries(RFBs).In this work,we propose a novel ZIF-8-assisted etching approach to form holey fibers in the electrospinning process of aligned electrode structures.The etching approach allows the formation of holey fibers with small pores of~50 nm,offering large active surface areas for redox reactions,while the aligned macrostructure with the holey fibers of 3–5 lm in diameter ensures a high permeability along the fiber direction.The application of the prepared electrodes to a vanadium redox flow battery(VRFB)enables an energy efficiency(EE)of 87.2%at the current density of 200 m A cm^(-2),which is 13.3%higher than that with conventional electrospun carbon electrodes.Even at high current densities of 300 and 400 m A cm^(-2),the battery still maintains energy efficiencies of 83.3%and 79.3%.More excitingly,the prepared electrode yields a high limiting current density of4500 m A cm^(-2) and a peak power density of 1.6 W cm^(-2).It is anticipated that the present electrospinning method combining the ZIF-8-assisted etching approach with a way to form ordered fiber structures will allow even more high-performance electrodes for RFBs in the future.展开更多
基金financially supported by the grant from the Research Grants Council of the Hong Kong Special Administrative Region,China(T23-601/17-R)the National Natural Science Foundation of China(21703263)HKUST Fund of Nanhai(FSNH-18FYTRI01)。
文摘Fabricating electrodes with large specific surface area(SSA)and high permeability has been the longstanding target in redox flow batteries(RFBs).In this work,we propose a novel ZIF-8-assisted etching approach to form holey fibers in the electrospinning process of aligned electrode structures.The etching approach allows the formation of holey fibers with small pores of~50 nm,offering large active surface areas for redox reactions,while the aligned macrostructure with the holey fibers of 3–5 lm in diameter ensures a high permeability along the fiber direction.The application of the prepared electrodes to a vanadium redox flow battery(VRFB)enables an energy efficiency(EE)of 87.2%at the current density of 200 m A cm^(-2),which is 13.3%higher than that with conventional electrospun carbon electrodes.Even at high current densities of 300 and 400 m A cm^(-2),the battery still maintains energy efficiencies of 83.3%and 79.3%.More excitingly,the prepared electrode yields a high limiting current density of4500 m A cm^(-2) and a peak power density of 1.6 W cm^(-2).It is anticipated that the present electrospinning method combining the ZIF-8-assisted etching approach with a way to form ordered fiber structures will allow even more high-performance electrodes for RFBs in the future.
