Preparation And Electrochemical Performance Of Polyaniline Carboxylated CeO₂ Composite Materials

In recent years,polyaniline/inorganic composites have received a lot of attention because it can combine the characteristics of the both by synergistic effects to produce new materials with special functions.In addition,the inorganic nanoparticles treated with the surface modification technology can generate strong interaction with the PANI molecular structure to firmly bind the both and increase the structure and performance of the polyaniline/inorganic composite.Therefore,this dissertation focuses on the preparation and electrochemical properties of polyaniline/carboxylated CeO₂ composites and lays a foundation for t he development of electrode materials for supercapacitors.The specific research results are as follows:?1?H₂SO₄ and sulfosalicylic acid?SSA?were selected as codopants.Co-doped PANI was synthesized by in-situ polymerization at different reaction temper atures.The influence of reaction temperature on the performance of co-doped PANI was analyzed,and the electrochemical characteristics of co-doped PANI were discussed.The results showed that the co-doped PANI synthesized at the reaction temperature of10°C had the best conductivity and its conductivity reached 0.1003S/cm.FTIR,TG and XPS analysis results show that co-doped PANI?10°C?has a higher doping degree,oxidation state and thermal stability.The electrochemical performance test results showed that the co-doped PANI?10°C?exhibited smaller charge transfer resistance and ion diffusion resistance.The specific capacitance value of the co-doped PANI?10°C?at the current density of 0.5 A/g reached 106.9F g^-1 by calculation.?2?The carboxylated CeO₂ was prepared by surface modification technique,and PANI/CeO₂-COOH composites were synthesized by in-situ polymerization with aniline monomers in H₂SO₄ and SSA co-doped acid systems.The results show that the modification effect is better under the modificati on temperature of 80°C and the modification time of 4 h when the carboxyl modification is carried out in the high temperature modification stage.The ratio of Ce^{I I I}/Ce^{I V} of the carboxylated CeO₂ was approximately 1,indicating higher surface oxygen vacanci es.PANI/CeO₂-COOH composites exhibited short fibrous and a few nanoparticle-like microtopography,and the agglomeration phenomenon was significantly improved,indicating better thermal stability.In addition,the specific capacitance of PANI/CeO₂-COOH composites reached 133.1F g^-1 at current density of 0.5A/g.?3?The PANI-F/CeO₂-COOH composites with fiber morphology were synthesized by self-assembly method.The results show that there is a strong chemical bond between the carboxylated CeO ₂ and PANI-F,not only through simple physical coating.At the same time,P ANI-F/CeO₂-COOH composites have better thermal stability,which is mainly controlled by the thermal degradation of PANI and the thermal decomposition of the chemical bonds between th e PANI and CeO₂-COOH interfaces.In addition,fibrous PANI-F/CeO₂-COOH composites exhibited smaller charge-transport resistance and lower interfacial resistance.The specific capacitance value of PANI-F/CeO₂-COOH composites reached 242F g^-1 at current density of 0.2A/g.