Study On Modification And Performance Of Graphite Felt Electrode Materials For Vanadium Redox Flow Battery

In recent years,fossil fuel consumption and greenhouse gas emissions have led to people high demand for sustainable energy sources such as solar and wind power.However,their full utilization in power generation is limited to some extent by their intermittent nature.To overcome this problem,large-scale energy storage systems are needed to stabilize their energy output.Charging and discharging batteries are considered the most economical option.In the charge-discharge battery,the vanadium redox flow battery has attracted more and more attention because of its good energy storage performance,and has become one of the most attractive batteries.However,vanadium redox flow battery energy storage systems have low energy efficiency and severe polarization at high current densities,which limits their application in practical industrial applications.The electrode plays an important role in vanadium redox flow battery.The poor electrocatalytic activity of the electrode material greatly affects the performance of vanadium redox flow battery.This paper introduces the key materials of the vanadium redox flow battery,such as electrode,membranes,and the working principle of the vanadium battery.Based on the principle,the electrode materials were modified and improved the overall electrochemical performance of the battery,This work was mainly including:?1?Carbon mesh is used to make composite graphite felt electrode for vanadium redox flow battery.The electrode is made of p-phenylenediamine and phytic acid in situ polymerized on graphite felt fiber,and then calcined at high temperature in an inert atmosphere.Compared with the untreated graphite felt electrode,the carbon mesh modified graphite felt electrode has higher electrocatalytic activity for VO²⁺/VO₂⁺and V²⁺/V³⁺redox couples.The energy efficiency of the composite electrode was increased by 6%(current density:200 m A cm^-2).Based on the above structure design,the battery with composite electrode has good cycle stability and no obvious attenuation of energy efficiency after 1000 cycles.?2?Porous graphite felt?GF@P?electrodes are used to improve the electrochemical performance of vanadium redox flow batteries.The generation of pores on graphite felt electrodes is caused by the etching effect of iron on carbon.At a current density of 200 m A cm^-2,the voltage and energy efficiency of the porous graphite electrode battery reached 72.6%and70.7%,respectively,which were 8.3%and 7.9%higher than the untreated graphite felt.In addition,the vanadium redox flow battery based on GF@P electrode has very high stability after more than 500 charge and discharge cycles at 200 m A cm^-2.