Preparation And Properties Of The Membranes For Zinc-bromide Redox Flow Battery

Nowadays, pollution of the environment, lack of the fossil energy and a series of problems had been out, more and more countries around the world have got the recognition and attention to the United Nations Climate Change conference after Kyoto Protocol. And to improve the efficiency of energy utilization and develop cleaner energy is becoming the world’s attention. Therefore, we propose and develop some electrochemical system with novel, high quality, and low cost in order to meet the energy needs, including iron-bromine redox flow battery, all vanadium redox flow battery, zinc-bromine redox flow battery, etc.Zinc-bromide redox flow battery is a new type of electrochemical energy storage device, with the advantage of low consumption, high efficiency, less pollution and higher current density, etc. It adapts to times of the depth of the charge and discharge. Zinc-bromine redox flow battery is more suitable than other redox flow batteries for large energy storage because of higher efficiency and lower consumption. It mainly uses in power grid peak shaving, regional power supply and new traffic tools, etc. Zinc-bromine redox flow battery makes by plates, electrolyte, separator, electrode materials, etc.In this paper, we mainly study the preparations and properties of the membranes for zinc-bromine redox flow battery. The membrane is one of the most important components of zinc-bromine redox flow battery, and its role is to separate the positive and negative half redox flow battery and transport ion. Membranes on the market are expensive and have complex making craft. This paper focuses on this problems to produce polyvinyl alcohol/ PTFE composite membrane, polyvinyl alcohol/phosphomolybdic acid composite membrane. sulfonated polysulfone/PTFE membrane and SiO2 sulfonated polysulfone//PTFE composite membrane. And we make the physical-chemical test, ultraviolet spectrum test, infrared spectroscopy test, and thermal test of these membranes. We test the performance of zinc-bromine redox flow battery under assembling the membranes into the battery and analysis the comparison results.This paper uses solution-casting method to produce the polyvinyl alcohol/PTFE composite membrane and polyvinyl alcohol/phosphomolybdic acid composite membrane. These two membranes are based on polyvinyl alcohol. Polyvinyl alcohol is a kind of synthetic polymer materials with non-toxic and tasteless. Membranes are modified to have higher moisture content and higher rate of charging. We use PTFE with higher porosity as the base to enhance the mechanical strength of polyvinyl alcohol, and get polyvinyl alcohol/ PTFE membrane with better thermal stability. Phosphomolybdic acid is a kind of solid-acid, and it has strong ability of ion conductivity. It integrates polyvinyl alcohol and phosphomolybdic acid. Polyvinyl alcohol/phosphomolybdic acid has higher ion-exchange rate and water absorption rate. We optimize properties of the polyvinyl alcohol materials, having better suitable of the membranes for the zinc-bromide redox flow battery.The paper makes sulfonated polysulfone/ PTFE composite membrane by using sulfonated method and makes SiO2 sulfonated polysulfone//PTFE composite membrane in two different ways. Polysulfone membrane is a hot spot of the membranes for the zinc-bromide redox flow battery. This paper improves the ordinary polysulfone membranes on the market, obtaining more stable properties of the membranes for the zinc-bromide redox flow battery. According to the different materials and ways of sulfonation, we make the better suitable of the membranes for the zinc-bromide redox flow battery. The sulfonated polysulfone/PTFE membrane has larger moisture content than the SiO2 sulfonated polysulfone//PTFE composite membrane. The thermal stability of SiO2 sulfonated polysulfone//PTFE composite membrane keep good. In this paper, we produce four kinds of the membranes for the zinc-bromine redox flow battery. All of them have lower price and better properties than those on the market, for opening some new routes in diversification of the membranes for the zinc-bromine redox flow battery.