Synthesis and electrochemical properties of polyaniline/Co(OH)2–Ni(OH)2 nanocomposite electrode materials

Electrochemical supercapacitive properties of polyaniline (PANI)/cobalt hydroxide (Co(OH)2)–nickel hydroxide (Ni(OH)2) nanocomposite (NC) electrode materials, synthesized potentiostatically via a electrochemical deposition method, are explored and compared with PANI and Co(OH)2–Ni(OH)2 electrode materials. From the surface analysis, an amorphous PANI, NCs and Co(OH)2–Ni(OH)2 are entirely different from one another. The PANI surface demonstrates nanofibrous morphology, NCs exhibits nanofiber-platelet morphology and Co(OH)2–Ni(OH)2 endows platelet-type surface morphology. The electrochemical properties of the PANI, NCs and Co(OH)2–Ni(OH)2 electrode materials are obtained from the cyclic-voltammetry and galvanostatic charge-discharge measurements. The specific capacitances of PANI, NCs and Co(OH)2–Ni(OH)2 measured at a sweep rate of 10 mV/s in a 1.0 M NaOH electrolyte are found to be 0.59, 50.0–74.1 and 312.5 F/g, respectively. The retention values of PANI, NCs and Co(OH)2–Ni(OH)2 obtained at the same scan rate for 1000 cycles are 25.8, 70.5–57 and 42.4%, respectively. This work clearly illustrates the reasons for a weak electrochemical performance of PANI and its composites with Co(OH)2–Ni(OH)2 in alkaline electrolyte over Co(OH)2–Ni(OH)2 electrode material.