Production and characterization of polyaniline/Co3O4 nanocomposite as a cathode of Zn-polyaniline battery

Co3O4 nanoparticles were prepared by using ethylene glycol as solvent, urea as precipitant and cobalt acetate as precursor. The prepared Co3O4 nanoparticles were incorporated into polyaniline matrix during in situ chemical oxidative polymerization of aniline with different molar ratios of aniline: Co3O4 (40:1, 20:1, 13:1) using (NH4)2S2O8 as oxidant in aqueous solution of sodium dodecylbenzene sulfonic acid under N2 atmosphere. Room temperature conductivities of PANI, PANI/Co3O4 (40:1), PANI/Co3O4 (20:1) and PANI/Co3O4 (13:1) are 3.2 x 10-4, 5.1 x 10-5, 4.1 x 10-5 and 1.4 x 10-5 S/cm respectively, indicating decrease of conductivity with increase of Co3O4 in PANI due to the blocking of charge carriers. These charge carriers do not have sufficient energy to hop between favorable sites. PANI/Co3O4 NCs show paramagnetic behavior at 5 K. Electrochemical studies showed that Zn-PANI/Co3O4 (13:1) battery had delivered maximum discharge capacity (87.1 mAh g-1) as compared to Zn-PANI battery (50.1 mAh g-1) at constant current of 0.5 mA cm-2. At constant resistance of 1000 Ω, discharge capacities of Zn-PANI/Co3O4 (13:1) and Zn-PANI battery are 84.6 and 50.8 mAh g-1, respectively.