Catalase‐Based Air‐Cathode for Biocompatible Zinc–Air Battery

The use of catalase (CAT) from bovine liver as an electrocatalyst in the air electrode of a primary zinc–air battery (ZAB) with neutral electrolyte (pH 7.4) is reported. First, the use of Nafion for immobilizing CAT onto electrode surface allowed to obtain long‐term stability of the catalytic activity of CAT. Besides, analysis of the CAT and CAT‐Nafion as catalysts for oxygen reduction reaction (ORR) was carried out by linear sweep voltammetry (LSV) using a rotating ring‐disk electrode (RRDE), demonstrating a four‐electron ORR mechanism. Finally, CAT and CAT‐Nafion were tested as air electrodes in flooded ZAB and compared against human hemoglobin‐based ZAB. Our results demonstrated the significant influence of the protein coating of the heme groups on the ZAB performance, affecting greatly the discharge capacity and the power density.