Modification Of Carbon Felt And Its Application In Quinone-based Flow Battery

Quinone-based redox flow batteries have gained widespread attention,since they have advantages of high stability,outstanding output power,independent power and capacity,safety,being environmental-friendly,and high accessibility of their redox active materials.Selecting 2,6-DHAQ and K4Fe(CN)6·3H2O as redox-active electrolytes,assembled flow batteries and tested their performance.The carbon felt is modified by air thermal oxidation treatment,ultraviolet ozone(UV ozone,UVO)treatment,and nitrogen doping treatment.Through the analysis of the material structure,composition and performance of the treated carbon felt,the influence mechanism and optimal conditions of different treatment methods are determined.(1)Using air thermal oxidation treatment method,the best battery performance can be obtained under the condition of high temperature 600℃for 2 hours.On the basis of maintaining the efficiency above 99%,the capacity decay rate during each cycle is 0.0297%.Through analysis,it is believed that under this condition,as the amount of CO and C=O increases,the electron transfer ability of the carbon felt can be improved,and the interaction between the redox active material and the electrode surface will hinder the occurrence of side reactions.Including the formation and dimerization of anthrone.(2)UVO treatment has the advantages of simple operation and time saving for the modification of carbon felt.Through UVO treatment,the number and composition of oxygen-containing functional groups on the surface of the carbon felt were changed,and the influence of different oxygen-containing functional groups on the performance of flow battery was further explored.It was found that the increase of CO and C=O is beneficial to the energy efficiency and stability of the flow battery.Sexual improvement.(3)In the research of nitrogen doping modification,the carbon felt was modified by the hydrothermal method and the evaporating solvent method respectively,which effectively improved the coulombic efficiency,energy efficiency and cycle stability of the flow battery.In the research,the increase of C-N improves the battery performance.The carbon skeleton doped with negative N atoms can be free electrons,which can be used as new active sites to promote ion exchange.