Preparation Of High Temperature Membrane Electrolyte Based On One-dimensional And Two-dimensional Carbon Materials

With the depletion of fossil energy,the development of new energy sources has been imminent.Proton exchange membrane fuel cells(PEMFC),as one of the renewable energy sources with energy saving and environmental protection,has a broad development prospect.The proton exchange membrane is the core component in the proton exchange membrane fuel cell,and thus has been extensively studied.For the polymers without functional groups to conduct protons,the introduction of proton conduction carriers with the formation of composite membranes is an effective strategy to prepare PEMs with the outstanding proton conductivity.However,there is a potential risk of the components leakage due to the lack of the interaction force.Here,the composite of carbon nanotube oxide(OCNT)assembling with cadmium telluride(CdTe)and 1-butyl-3-methylimidazolium hexafluorophosphate(bmimPF6)was introduced into the system of phosphoric acid(PA)doping poly(vinylidene fluoride)(PVDF)with the formation of PVDF/OCNT-CdTe-bmimPF6/85%PA membranes.PA molecules are anchored by the inorganics of OCNT-CdTe-bmimPF6 and are stabilized in membranes.The high and stable proton conductivity values at the elevated temperature are obtained comparing the reported PVDF/bmimPF6/PA membranes.Specifically,the proton conductivity value could reach 1.28×10-1 S/cm at 160℃ and the value is stable 1.70×10-2 S/cm at 120℃ lasting for 350 h.The fine stability in components could make the membranes extricate from the predicament of proton conductivity decline exceeding 120℃ under anhydrous conditions in PVDF/bmimPF6/PA membranes.With the extensive research on fuel cell applications,proton exchange membranes need to be frequently replaced due to problems such as lifetime and catalyst poisoning,thus preparing a proton exchange membrane that is easy to carry.We further studied the mechanical properties of proton exchange membranes by designing materials that have both good elasticity and self-healing properties.Currently,various reversible bonds or dynamic interactions have been used for self-healing materials,which provide flexibility to the proton exchange membrane,reversible covalent bonds or cross-linking reactions,free radical dimerization,and cycloaddition reactions can lead to reproducible healing.However,the repair of such materials always requires the input of external energy.Dynamic van der Waals forces ensure autonomous self-healing because these interactions are easily dissociated after strain is applied and are easily re-associated at room temperature.However,materials based on weak van der Waals forces are relatively soft and have poor elasticity.Therefore,we use a carbon material which has excellent elasticity and Young’s modulus to introduce a polymer membrane formed in a phosphoric acid doped polymer system,and the dynamic van der Waals force of the modified carbon material and the phosphoric acid molecule ensures the membrane.The self-repairing ability also improves the mechanical properties of the membrane.