Effect of Seawater pH Value on Anode Performance of Aluminum-Air-Seawater Batteries

The corrosion behavior and discharge behavior of Al alloy in seawater with different pH values were investigated based on measurement of polarization curves, electrochemical impedance spectra and constant current polarization curves as well as observation of scanning electron microscope, aiming at revealing the effect of increasing pH value of seawater on the corrosion behavior and discharge behavior of Al anode of the Al-air-seawater batteries.Results show that the corrosion potential of Al alloy gradually decreases with increasing seawater pH value,accompanied by increase of corrosion rate and widening of passivation region.Secondary passivation occurred at a seawater pH value of 9.10.In the meantime,with the increase of seawater pH value,the polarization of Al alloy discharged at a constant current was significantly enhanced and the potential moved towards the positive direction,thereby affecting the discharge properties of the batteries.