The Fabrication And Functionalization Of The Key Material And Research On Their Cell Performance For All Vanadium Redox Flow Battery

It is mainly because of primary total energy consumption people turn to secondary energy such as wind,solar,and tidal energy,unfortunately the secondary energy has a major shortcoming:it is non-continuity.Redox flow batteries(RFBs)will be good to solve the defect as large-scale energy storage device.All vanadium redox flow battery(VRFB),plays a dominant in the system of RFBs,the energy density in the VRFB is determined by the concentration of the vanadium species and the volume of the reservoirs.Moreover,the crosscontamination problems could be avoided because of the enlisting of the same element,V,in both the anodic and cathodic electrolytes.For its long cycle life,most attractive energy conversion system,can be charged and discharged rapidly and high reliability,the advanced characteristics of VRFB which is why do scientists continue to pursue them.The main contributions of this dissertation are summarized as follows:(1)Demonstrate a facile preparation of N,O dual-doped carbon felt(CF)as electrodes in all-vanadium redox flow batteries(VRFB).The CF which exhibited a great deal of stability and excellent electrochemical activity by N2 and O2 plasma treated,the discharge voltage plateau increase 0.18V compare with pure.The energy efficiency of the as-assembled VRFB is improved from 65%(pristine)to 78%(doped)at a current density of 50 mA cm-2,and increase of 13 percent compared with pure,the published experimental data in literature is generally increase 6%?7%.(2)The first time a novel carbon felt electrode modified with carbon nitride(C3N4)at high temperature,which developed to improve the electrochemical performance with a V02+/VO2+ redox pair.The graphitic C3N4 on carbon felt exhibited an excellent performance in a VRFB which highlights higher peak current density and the date of Ipa/Ipc close to 1,the ?E shrink from 0.59V to 0.16V,which illustrates the reversibility was improved of the electrode reaction.Besides,the EE has risen by 9.1%.(3)Present a method of using plasma to modify Nafion membrane as ion exchange membrane for vanadium redox flow battery.This was the first time,Nafion was surface modified with plasma which being simple to operate and shot processes in less time than the usual chemical process.The results shows increase the energy efficiency by almost 6%in plasma modified Nafion membrance.And the membrance's electrical conductivity are up to 3 times.