Synthesis and characterization of polyaniline–Fe3O4 nanocomposite: Electrical conductivity, magnetic, electrochemical studies

Fe3O4 nanoparticles were prepared by hydrolysis reaction of urea in ethylene glycol as solvent at 160 °C. The prepared Fe3O4 nanoparticles were incorporated into polyaniline (PANI) matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline:Fe3O4 (19:1, 16:1, 12:1, 9:1) using (NH4)2S2O8 as oxidant in aqueous solution of sodium dodecylbenzene sulphonic acid under N2 atmosphere. Room temperature conductivities of the synthesized PANI, PANI/Fe3O4 (19:1) and PANI/Fe3O4 (9:1) are 3.2 × 10−4, 1.8 × 10−5 and 1.0 × 10−5 S/cm, respectively, indicating decrease of conductivity with increase of Fe3O4 in PANI. Saturation magnetizations of Fe3O4, PANI/Fe3O4 (19:1), and PANI/Fe3O4 (9:1) are 27.5, 5.5 and 6.3 emu/g, respectively, indicating an increase of ferromagnetic interaction with more incorporation of Fe3O4 in PANI matrix, whereas PANI is diamagnetic. Electrochemical studies shows that Zn-PANI/Fe3O4 (9:1) battery had delivered maximum discharge capacity (78.6 mAh/g) as compared to Zn-PANI battery (50.1 mAh/g) at constant current of 0.5 mA cm−2. At constant resistance of 1000 Ω, discharge capacities of Zn-PANI/Fe3O4 and Zn-PANI battery are 73.37 and 50.8 mAh/g, respectively.