The optimization of the pore structure for the air electrode plays a crucial role in enhancing electrochemical per-formance of the electrode.The oxygen transmission rate can be enhanced,leading to achieve high energy density and long discharge life of metal air batteries by the recombination of the porous electrode structure.In the forming process of air elec-trode,the effects of calcination temperatures(200,250,300,350,400 ℃)on the apparent morphology,micropore structure,and electrochemical performance of the air electrode were investigated using scanning electron microscopy,differential ther-mal analysis,specific surface area measurement,wetting angle determination,and electrochemical testing.Additionally,the discharge performance of the Mg-based air battery was further evaluated.The results showed that the fiber melting state of PTFE binder in air electrode changed the distribution of micropore structure(including air inlet and liquid inlet)via the in-crease of heat treatment temperature,which affected the oxygen reduction electrochemical performance and the discharge life of air electrode.In particular,the air electrode prepared at a calcination temperature of 350 ℃,which was close to the PTFE phase transition point(343 ℃),exhibited the uniform pore size distribution and the optimal hydrophobic characteris-tics(including hydrophobic points and gas diffusion channels).As a result,the air electrode demonstrated the minimum electrode polarization(with an electrode current density of 159.1 mA/cm2 at a polarization potential of-0.45 V),the longest discharge lifespan(with a discharge time of 39.0 h at a current density of 15 mA/cm2),as well as high capacity and power density(37.4 A·h and 13.05 mW/cm2,respectively).
air electrodecalcination temperatureelectrochemical propertymetal air battery
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