The Fabrication Of Polyphenylene Oxide Anion Exchange Membrane Functionalized With Morpholine

The direct combustion of fossil fuel causes low energy utilization rate and environmental pollution,so more and more attention is paid to new clean and efficient energy conversion.Anion exchange membrane fuel cell has many advantages,such as Alkaline environment,High electrode catalytic activity and the access to use non-precious metals catalyst.AEM is the important part of Anion exchange membrane fuel cell,which has the function to isolate the direct contact of fuel to oxidant and promote the transport of hydroxide ion.However,its disadvantages limit the commercial use,such as low conductivity,mechanical strength and poor alkali stabiliy.Here a novel strategy is proposed to improve the mechanical strength and conductivity.We synthesised BPPO with different degree of bromation,and then functionalized BPPO with N-methyl morpholine to make the PPO-MmOH membranes.The best PPO-MmOH membrane has highest conductivity,28 mS cm^-1 and its swelling ratio and water uptake is33%and 106%.The conductivity increases when the degree?<40%?increases,but it decreases when the degree is over 40%.PPO-MmOH membranes have good alkaline stability because of the use of N-methyl morpholine.In order to improve the mechanical strength of PPO-MmOH membrane with high degree of bromation,crosslined anion exchange membranes were fabricated.The Dm-BPPO membrane crosslinked by bis?2,2-morpholinoethyl?ether was immersed in 10.wt%N-methyl morpholine water solution at 60?for 24 h to make Dm-PPO-MmBr membrane.The best Dm-PPO-MmOH membrane with 37%degree of crosslink has highest conductivity,35 mS cm^-1,and good mechanical strength.Dm-PPO-MmOH membranes have good alkaline stability because of the use of N-methyl morpholine.In order to improve the the continuity of water channel and the strategy above which can be only used to functionalized Dm-BPPO with high degree of crosslink,we added different amount of PVA to the anion exchange membrane to make PVA-Dm-PPO-MmOH.This kind membrane can be functionalized more easily by immersing in 10.wt%N-methyl morpholine water solution at 20?for 24 h.The best PVA-Dm-PPO-MmOH membrane with 4%PVA has highest conductivity,42 mS cm^-1 at room temperature,and the swelling ratio and water uptake is 33%and 112%.The properties are kept at high temperature,.the conductivity 91 mS cm^-1,swelling ratio 30%and water uptake 88%.Its open circuit voltage is 1.03 V and the peak power density shows 202 mW cm^-2.