Preparation And Properties Of Ferrocene Modified Polyaniline And Its Composites

As a member of conjugated conducting polymers,poly aniline(PANI)was considered to be an attractive choice for supercapacitors electrode materials,because of its high charge density.However,it usually suffered from relatively low power density,large resistance and cyclic instability.Meanwhile,the electrical properties were affected by its doping condition.In order to improve the properties,PANI was modified through ferrocene derivatives with rich-electronegativity,and combined with graphene.Furthermore,the preparatio,structure,morphology and electrochemical properties of the as prepared conducting polymers and composite materials were studied systemically.With ferrocene as raw materials,a novel monomer named 1,1’-ferrocenediacyl anilide(FcA)was synthesized through F-C acylationreaction,oxidation,Acyl chloride reaction and amidation in turn.The structure of FcA was determined by FTIR,1H NMR and UV-Vis,the result showed the novel monomer existed highly delocalized conjugated system.The electrochemical activity of FcA was slight declines compared to ferrocene(Fc),but the reversibility of oxidation-reduction reactions was promoted.Using chronoamperometry,the as measured the electrode surface diffusion coefficient was 2.71×10-6 cm/s.Copolymerization between FcA and aniline(ANI)was carried out through a chemical oxidation method.The structure of copolymer[P(FcA-co-ANI)]was characterized by using FTIR,XPS,XRD and SEM,the results showed the copolymer was amorphous with a low degree of a local order.The influence of monomer molar ratio and amounts of initiators on the performance of copolymer was investigated.The experimental conditions,the optmized electrochemical properties appeared when monomer ratio(ANI:FcA)was 1:4 and initiator amount was 20 wt%.In the same experiment conditionthe,the specific capacitance of P(FcA-co-ANI)could up to 413.1 F/g at 0.5 A/g,and electric conductivity was 1.26 S/cm,the results were better than those of PANI.Two kinds of composites of P(FcA-co-ANI)and reduced graphene oxide(rGO)were prepared through oxidation polymerization,by using P(FcA-co-ANI)and reduced graphene oxide as organic and inorganic components,respectively.In the system of P(FcA-co-ANI)-base composite,the optimal proportion of total monomer mass to rGO was 50:2,the specific capacitance of composite I(marked as P2-rGO)was 226.3F/g at 3 A/g,electric conductivity was 1.82S/cm and specific surface area was 48.36 m/g,respectively.In the system of rGO-base composite,the optimal proportion of total monomer mass to rGO was 50:100,the specific capacitance of composite II(P-rG04)was 351.2F/g at 3 A/g,electric conductivity was 6.69S/cm and specific surface area was 73.82 m2/g,respectively.The structures of two kinds of composites were characterized through FTIR,UV-vis,XRD,SEM and TEM.The results indicated the composites were prepared successfully,the P(FcA-co-ANI)-base composite was formed a homogeneous phase,and rGO-base composite was formed a three-dimensional structure.The electrochemical performances of P2-rGO and P-rG04 were studied in details,the results showed that the specific capacitance of P-rG04 was 670.2F/g at 0.5 A/g,and displayed excellent cycling stability,with specific capacitance retention of 88.36%after 1000 cycles.In comparison,the specific capacitance of P2-rGO was 451.2F/g at 0.5 A/g,and the specific capacitance retention of 885.23%after 1000 cycles.Four kinds graphene oxide products with different functional groups were prepared,including graphene oxide(GO),reduce graphene oxide(rGO),aminated graphene oxide(NGO)and sulfonated graphene oxide(SGO).XPS and FTIR results indicated that four kinds of graphene oxide had been synthesized successfully,the sequence of electric conductivity was rGO>NGO>SGO>GO.In order to explore the effect of graphene surface chemistry on the electrochemical performance of electrodes based on P(FcA-co-ANI)composites.Four different P(FcA-co-ANI)-graphene composites were fabricated through selecting graphene oxide,and marked as P-GO,P-rGO,P-NGO and P-SGO,respectively.The structures of composites were characterized through XPS,FTIR and SEM.The BET analysis indicated that he sequence of specific surface area was P-SGO>P-NGO>P-rGO>P-GO,and the specific surface area of PSGO could up to 83.25 m2/g.Under the same condiction,the electrochemical performance of four kinds of composites were analyzed and compared,the sequence of electric conductivity was P-rGO(26.69 S/cm)>P-SGO(20.36S/cm)>P-NGO(16.78S/cm)>P-GO(7.67 S/cm),the sequence of specific capacitance was P-SGO(763.8 F/g)>P-NGO(632.5 F/g)>P-rGO(601.7 F/g)>P-GO(151.2 F/g).Moreover,P-SGO displayed excellent cycling stability,with specific capacitance retention of 95.59% after 1000 cycles.