Electrochemical Properties Of Polyaniline/nano-nickel/carbon Nanotube Composites

Polyaniline(PANI)is a kind of electrode materials for its high Faraday pseudo capacitance,however its applications in practice are limited because of its'electrochemical utilization rate and high capacity multi-cycle decay rate.Nickel nanoparticle has attracted intense research interests for it's potentially applied in a wide range of fields such as magnetic storage,magnetic fluid,medical diagnosis,conducting paints,rechargeable batteries and catalysis.Carbon nanotubes(CNTs)are considered as an excellent matrix owing to their special structure and properties.However,the lower specific volume because of the utilization of low specific surface area of CNTs limited its application as an electrode material.Recently,the synthesis of carbon nano tubes and metal composites has become one of the hot spots in carbon nanotubes field.In this paper,nickel nanoparticles/carbon nanotube composites were prepared by hydrothermal method while carbon nanotubes are acidification as the template.Based on this composite,PANI/Ni/MWCNTs composite is prepared and its structure and property are characterized.The different ratios of Ni/MWCNTs composite materialsis are prepared by the hydrothermal method with hydrazine as the reducing agent.The nickel composite particle shows smaller particle size,uniform size,good dispersion and the best electrochemical performance when the nickel salt and the carbon nanotubes has the mass ratio of 7:1.Using self-made Ni/MWCNTs composites modified carbon electrode as working electrode,the electrochemical behavior of p-nitrophenol in the solution is investigated.The results suggested that MWCNTs were electrochemical active with the modification ofNi.Compared with carbon electrode,the redox peaks greatly improved and it's a new method for detecting the p-nitrophenol in water solution.The core-shell structure PANI/Ni/MWCNTs composites which composition the Ni/MWCNTs as the core and the PANI as the shell were prepared by in situ polymerization using Ammonium persulfate(APS)as oxidant.The electrochemical properties of materials were studied by the cyclic voltammetry test,galvanostatic charge/discharge test and impedance measurement of different percentage of Ni/MWCNTs in the ternary core-shell composite.The specific capacitance of the electrode material prepared by the optimal condition is 737.13F/g,measured at the scanning rate of 0.001V/s by cyclic voltammetry.Its supercapacitor could achieve the specific capacitance of 50.86F/g at the current density of 10mA/cm2.