Preparation And Performace Of Acid-base High Temperature Proton Exchange Membrane Modified Modified By CS

Polymer electrolyte membrane fuel cells?PEMFCs?are promising candidates for electrical power due to their high energy efficiency and easy manipulation.Proton-exchange membrane?PEM?is one of key components of PEMFCs,which directly influences the fuel cell final properties.At present,perfluorosulfonic acid membranes such as Nafion membranes are widely used for low temperature PEMFCs.But commercial Nafion membranes do not satisfy the need because of low proton conductivity and weak heat stability under high temperature and low humidity.Besides,the high price and complex preparation process have also prevented Nafion membranes from spreading and popularizing.Therefore,in recent years,many efforts have been made to develop membranes with excellent chemical and thermal stability,low cost and high proton conductivity.In this study,we have prepared two kinds of polymer proton exchange membranes using ATMP as proton conductor,as following lists:?1?One kind of acid-base high temperature proton exchange membrane was synthesized from chitosan?CS?and amino trimethylene phosphonic acid?ATMP?by sol-gel process.FTIR spectroscopy and XRD suggest that amino group and phosphoric acid appears acid-base reaction forming ionic bond.The membranes we prepared have excellent thermal stability and can be safely used up to 180?Otherwise,the membranes also have high IEC values and water uptakes,excellent oxidative stability.SEM reveals that the surface of the membranes is dense,uniform and no separate phase.?2?One kind of acid-base high temperature proton exchange membrane was synthesized using ATMP as acid,CS and APTES as base.FTIR spectroscopy reveals the amino group and phosphoric acid appears acid-base reaction forming ionic bond and siloxane appears hydrolysis-polycondensation yielding Si-O-Si network.The XRD results suggest that CS/ATPES/ATMP membranes have a decrease in crystallinity and hence increase the amorphous phases in the membranes,which is helpful to proton transport.The TG-DSC and DTG curves show CS/APTES/ATMP membranes are thermally stable up to 180?.In addition,the water uptake as well as the oxidative stability decreases with the increase of ATMP content.The IEC value has an increase because of the introduction of ATMP.The proton conductivity of the blend membranes increases with increasing temperature,reaching the value of0.0578S.cm^-1 at 140?under nominally anhydrous condition.