Study On The Preparation And Performance Simulation Of Amphoteric Polysulfone Membrane For Vanadium Battery

Among all the energy storage techniques,the all-vanadium flow battery（VRB）has become the focus of research by domestic and foreign researchers due to its high efficiency,good battery performance,and no cross-contamination of the electrolyte.Among the various components of the vanadium battery system,the separator is crutial and determines the battery performance of the all-vanadium flow battery.At present,domestic and foreign researchers are looking for low-cost,good mechanical properties of non-perfluorosulfonic acid ion membranes to alternate Nafion membrane.Among them,polysulfone（PSF）is widely studied by researchers due to its resistance to stretching,creep,high thermal stability,and chemical resistance at high temperatures.In this paper,anionic and cationic monomers were aimined to be grafted on polysulfone by atom transfer radical polymerization（ATRP）.By adjusting the anionic and cationic monomers,a PSF amphoteric ion exchange membrane with high ion conductivity and low vanadium permeability was obtained and applied to All vanadium flow batteries.In this paper,based on the preliminary research of our group,the polysulfone chloromethylation experiments were further optimized.Using three factors and three levels of orthogonal experiments,the most suitable experimental conditions for polysulfone chloromethylation was investitaged by starting from the reaction time,reaction temperature and the amount of catalyst to find.When the reaction temperature is 55℃,the reaction time is 16h,and the amount of catalyst is 1g,the degree of chloromethylation of polysulfone is the highest,which can reach up to 2.32mmol g^-1.The three-factor three-level orthogonal experiment was used to optimize the experimental conditions of the grafting rate of chloromethylated polysulfone.At different temperatures,reaction times and monomer concentrations,the optimal grafting experimental conditions were 50℃.4h,0.5mol L^-1.Comsol Multiphysics software was used with a vanadium battery model to simulate the penetration of vanadium ions and the self-discharge process of the battery.It can be seen from the simulation that the main reason which affects the penetration of vanadium ions is the state of the electrolyte and the influence of the separator.However,the theoretical model needs to be further revised to consider more factors,such as the effect of water migration on the penetration of vanadium ions.Finally,the energy storage prospects and advantages of all vanadium flow batteries were analysed,the situation of vanadium batteries in the energy storage market and the cost of polysulfone grafted sodium styrene sulfonate membrane were estimated,and the prospects of ATRP modified membrane technology were also analyzed.