Modification Of High-performance Carbon-based Electrode For Vanadium Redox Flow Battery

Vanadium redox flow battery?VRFB?has been paid much attention due to long life,high energy efficiency and environmental friendliness.Electrode,as one of key components,affects overall energy storage property of VRFB.Various ways were used to modify carbon-based electrode for VRFB.The main researches are as follows:A one-step molten salt way was used to prepare porous and N/O co-doped graphite felt with KClO₃ and NH₄ Cl as active agents.The effect of KClO₃ and NH₄ Cl amount on morphology and electrochemical activity of graphite felt was studied.Graphite felt is uniformly etched with increase of wettability and O,N contents,improving its electrocatalytic activity.GF/ON-2 has the best electrocatalytic activity.The modified cell has good rate property and cycling stability.It retains higher capacity?1426 m A h?and energy efficiency?67.2%?at 260 m A cm^-2.Its capacity retention after 200 cycles is 59.1%,much higher than that of pristine?25.9%?.MOF UiO-66 was in situ deposited on graphite felt by hydrothermal method.It was changed to ZrO₂@C/GF via high-temperature calcination.The dosage of ZrCl₄ and terephthalic acid has an effect on morphology and electrochemical activity of electrode.ZrO₂@C/GF-1.4 has the best electrochemical activity.The modified cell shows excellent rate property and cycling stability.After 200 cycles,its capacity retention is 67.8%,which is 28.5% higher than pristine cell.A one-step way was used to obtain porous,graphitic and oxygen-functionalized carbon nanofiber.K2 Fe O4 is decomposed to KOH and Fe at high temperature to increase micropore,graphitization,and oxygen groups of carbon nanofiber at the same time.The modified carbon nanofiber has good wettability,large specific surface area,and high graphitization degree.Abundant oxygen groups can provide more active sites for vanadium redox reaction,accelerating electrode reaction.By contrast,one-step way is milder and more efficient than two-step way?KOH and FeCl₃?.The effect of K2 Fe O4 amount on morphology and electrochemical activity of carbon nanofiber was studied,and CNF-PF-3 is the best activity.The modified cell has better overall energy storage property.Figure 58;Table 7;Reference 82...