The hydrogen evolution reaction of the anode is a severe barrier that limits the further commercial application of Al-air batteries. Therefore, this study introduces a bifunctional membrane for the inhibition of hydrogen evolution in Al-air batteries. The reference to Al2O3@PAN as "bifunctional" means that it has both hydrophobic and anti-corrosion functions. Al2O3 can effectively inhibit the migration of hydroxide ions, and PAN is an excellent hydrophobic material. The bifunctional membrane is placed between the aluminum anode and the electrolyte, which can prevent the invasion of excess water and hydroxide ions, thereby inhibiting the hydrogen evolution corrosion of the anode. Electrochemical tests have confirmed that the corrosion inhibition rate of a bifunctional membrane containing 1.82 wt. % Al2O3@PAN is as high as 89.24%. The specific capacity of Al-air batteries containing this membrane can reach 1950 mAh/g, and the utilization rate of the aluminum anode has reached 61.2%, which is helpful in reducing the waste of aluminum resources. The results prove that the bifunctional membrane has excellent anti-corrosion properties. Bifunctional membranes can also be used to prevent the corrosion of metals in other fields.
Keywords: Al2O3@PAN; Al–air battery; anti-corrosion; bifunctional membrane; hydrogen evolution reaction.