Anisotropic Anion Exchange Membrane And Three-in-one High Efficiency Catalyst Based On Phthalocyanine

Phthalocyanine（Pc）is a kind of macrocyclic conjugated compound,which consists of 8 N and 32 C atoms.It has a special two-dimensional conjugated structure with 16centers and 18 pi electrons.The center of the phthalocyanine ring can coordinate with iron,copper,zinc or other metal elements to form metal coordination compounds.Researchers can optimize the structure of the molecules to obtain the required properties.In this paper,two aspects of work have been carried out around the study of phthalocyanine in fuel cells.The first work of this paper is focused on Anion exchange membranes（AEMs）.AEMs act as barrier to oxidants and reductants.High ion conductivity,lower membrane resistance,as well as good mechanical properties and strong chemical stability are required by AEMs.On this basis,by balancing the self-aggregation advantage of Pc macrocycles with its weak alkaline,the quaternary ammonium phthalocyanine was introduced into the brominated poly（2,6-dimethyl-1,4-phenylene oxide）（BPPO）ring to form AEMs.The conductivities of the synthesized AEMs can reach 236.2 mS?cm^-1@80℃.At the same time,the strongπ-πinteraction between phthalocyanine macrocycles forces the positively charged head groups to aggregate to form ordered hydroxide ion channels.Trimethylamine（TMA）monomers were also grafted to BPPO polymer chains to increase the OH^-mobility in the head group region.The formation of a5 nm OH^-channels in AEMs was confirmed by synchrotron radiation and transmission electron microscopy.Density functional theory and molecular dynamics calculations were performed to reveal the theoretical basis of this extreamely high OH^-conductivity in AEMs.Finally,hydrogen-oxygen fuel cells were assembled to evaluated the performance of the synthesized AEM in practical use.The peak power density can reach345 mW?cm^-2,which is among the best performances compared with similar works.The other reseach of this parer is focused on the catalytic properties of Pcs.Oxygen Reduction Reaction（ORR）is the crucial step for all kinds of fuel cells.Generally,a catalyst layer with a porous structure is elaborately designed to enhance ORR,in which catalyst particles,electron conductors,ion conductors must be fully mixed and well dispersed to expect that almost all catalyst particles stay at the cross of the four channels,i.e.,oxygen gas feeding,electron conducting,ion transporting,as well as water draining channels.Only if the all four channels were successfully open into the catalyst particles,their catalytic function would work.Otherwise,the absence of anyone among the four channels toward the catalyst particles will absolutely lead to ORR interruption.In this report,we designed and synthesized a 3-in-1 polymer which like a triathlon athlete,gathers catalysts,electron conductor and ion conductor in its own body.The interspace between the polymer chains play the oxygen gas transport channels.Therefore,the catalyst layer consisting of the invented 3-in-1 polymer has an unexpectedly high catalyst utility.The performance of a Zn-air battery catalyzed by the invented 3-in-1 polymer is even much better than the one by commercial Pt/C catalyst owing to the high catalyst utility of the 3-in-1 polymer catalysts.To our knowledge,such a 3-in-1 polymer like a triathlon athlete has not been reported yet.We believe the invented 3-in-1 polymer may open up a new path in stepping up fuel cells commercialization.