Preparation Of SPEEK / GO Series Proton Exchange Membrane And Application Of Vanadium Battery

With traditional energy supplies increasingly exhausted and a series of environmental problems caused in the process of using the shortage of traditional energy become increasingly serious, so the growing, renewable energy sources such as solar energy and wind energy and so on have been developed urgently. As we know all of these new energy sources need to be equipped with energy storage devices due to some instability issues during use. Compared with other energy storage devices, vanadium redox flow battery (VRB) has become one of the most development potential energy storage devices because of its longer life, faster response of charge and discharge, higher energy efficiency and lower cost et al. The membrane is a core component of VRB, its performance and price has always been the critical factors to restrain the VRB’s performance and application. This paper aims to develop a modified graphene oxide/sulfonated poly (ether ether ketone) ion exchange membrane and carry out research on its battery performances.Sulfonated poly (ether ether ketone) (SPEEK) was obtained by sulfonation of poly (ether ether ketone) (PEEK) in the concentrated H2SO4 (ca.98%). A series of SPEEK/GO blend membranes were prepared with various mixing mass ratios and research these blend membranes’water uptake(WU), ion exchange capacity(IEC), proton conductivity, vanadium ion permeability, thermal stability, oxidation stability, mechanical properties and cell performance. The WU and IEC decreased with the increase of GO, the mechanical properties increased with increasing GO content, the blend membranes have batter thermal stability and chemical resistance and lower permeability of vanadium ions than Nafion115. In VRB single cell test, the blend membranes expressed higher cell efficiency compared with Nafionll5, the EE of S/GO-2 (GO,wt2%) blend membrane was 80% compared to that with Nafion115 increased about 9%. The S/GO-2 blend membrane showed stable performance up to 100 cycles test.Experimental results showed that the transporting ions ability of GO was incapable. To improve the performance of the membranes for functional group modification on the surface of GO.GO derivatives containing sulfonic acid groups (GO-SO3H) were named as SGO. The SPEEK/SGO blend membranes (S/SGO) were prepared with various mixing mass ratios. The results showed that added SGO decreased the vanadium ion permeability of blend membranes, and SEM showed that the SGO was evenly dispersed in SPEEK. WU increased with the increase of SGO. The S/SGO-1(SGO, wtl%) showed better vanadium resistance ability and possessed better ion selectivity than that of Nafion115. In the VRB S/SGO showed higher cell efficiency than Nafion115 and the energy efficiency (EE) of S/SGO-1 was 87.8%, and the S/SGO-1 showed good cycle stability.GO derivatives containing amino groups were named as GO-NH2. These SPEEK/GO-NH2 blend membranes(S/GO-NH2) were prepared with various mixing mass ratios. Results indicate that added the GO-NH2 decreased WU and IEC of the blend membranes; the blend membranes have good mechanical properties, thermal stability. The S/GO-NH2 possessed lower vanadium ion permeability than that of Nafion115 and the ion selectivity was about seven times than of Nafion115. In the VRB performance test the cell efficiency of S/GO-NH2 were higher than that of Nation 115, the S/GO-NH2-2 (GO-NH2, wt2%) was the highest of them, the coulombic efficiency (CE) was 97.2% and the energy efficiency (EE) was 89.5%. The self-discharge time only less than one-tenth of Nafionl 15.