Synthesis And Property Study Of Proton-conducting Materials Based On Coordination Polymers

Due to the characteristic of high power transition,low noise and pollution,high mobility,proton-exchange membrane fuel cell(PEMFC)has attracted more and more attention.While the expensive cost of Perfluorosulfonic acid films still constrain its universal application.Thus,research on new type of proton-conducting materials has become the key point in this field.In this paper,we synthesized two kinds of compound and studied their proton-conducting behavior.Coordination Polymers(CPs),as an emerging candidate for proton-conduction porous solid electrolytes,is promising for its tunable periodic nanoscale channel,and diverse possibility of functionalization.In this paper,we synthesis a CP with water cluster,Zn2-(H2O)12.We also have studied the proton conduction behavior of it with the form of pellets via alternating current impedance plots.Without any other proton generator,proton conductivity of Zn2-(H2O)12 achieve 4.88 mS·cm-1at 25°C,95% RH.This study has shown the closely packing mode of water increase the occupancy of water guest molecules and the concentration of both proton generators and carriers.Also,the 3-D connectivity of the coordination polymer promote the proton transportation of vehicle mechanism.In another way,the(H2O)12 cluster is close enough and the connect with each other along b-axis,which lead to the construction of long-range hydrogen-bond network along b-axis and promote the proton conduction of Grotthuss mechanism.Through the investigation in this paper,we found that in order to promote the proton conduction of CPs,we not only need the proper double direction selection of guests and frameworks,but also a better design to make the arrangement of guest molecules more uniform and more importantly,more closer.Only in this way,could we maximize the proton-conducting ability of guests and push forward the CPs to practical application.Polyacids is facile and with strong acidity.Thus,it is a good option to add polyacid as guest to metal-organic frameworks(MOFs).Instances of polyacids added to MOFs have been reported already.The natural acidity of polyacid and the reservation ability for polyacid of MOFs make them a good partner in the application for proton-conducting.In this paper,we select NENU-5 as subject to explore the condition of addition of small guest proton carrier to promote the proton-conducting ability of NENU-5.By varying the pH condition,we have found adding NH3 molecules when pH=6,the proton-conduction value of NENU-5 could achieve 2.38×10-4 S·cm-1.