Functional metal‐porphyrazine derivatives and their polymers, 10. Secondary fuel cells based on oxygen reduction on platinum electrode modified by polymers and metal‐phthalocyanines

Secondary fuel cells based on oxygen reduction of platinum electrode modified by polymers and metal‐phthalocyanine (Mt = Fe(III), Co(II), Ni(II), and Cu(II)) were studied. The discharge curves for the platinum electrode modified by poly(2‐vinylpyridine) (or polystyrene) and Co‐phthalocyanine in 30% KOH aqueous solution, for a 30 min charge at 500 μA, followed by a 100 μA discharge showed a stable plateau at about −0.24 V SCE (Saturated Calomel Electrode). The open circuit voltage (vs. Zn) of the cell was 1.2 V, and the discharge capacity was of 46 A · h/kg. For this battery there was no significant decay in its characteristics after more than 30 charge‐discharge cycles. In Mt‐phthalocyanines, the values decreased in the order of Co(II) > Fe(III) > > Cu(II) > Ni(II). From a cyclic voltammogram for the electrode modified by the polymer and Co‐Pc, the cathodic reactions were discussed.