Oligomeric phthalocyanine modified polyaniline — an electrode material for use in aqueous secondary batteries

Polyaniline (PANI) and oligomeric phthalocyanine (PPC) are prepared and characterized by spectroscopic and analytical methods. They are blended in different proportions and their blends are characterized by cyclic voltammetry, electrochemical impedance measurements and are studied as electrodes in aqueous secondary batteries. The cell Zn/0.1 M ZnSO4/PANI—PPC is constructed and its charging—discharging behaviour is studied at different current densities. The effect of oligomeric phthalocyanine content on the cycle stability and the cell performance was also studied. The impedance spectra of the system were studied in two-electrode and three-electrode modes. The charge transfer resistance is found to be potential dependent. The complex impedance of the system is found to be independent of frequency at high frequencies and it shows a complex capacitive behaviour at low frequencies. The cell shows a maximum capacity of 93.3 Ah kg−1 for a particular ratio of PANI to PPC in the system. The current efficiency was close to 100% over at least 1000 complete cycles when cycled between 1.2 to 0.6 V at a constant current of 0.9 mA cm−2. The cell performance is stable at current densities ranging from 0.9 to 10 mA cm−2.