Preparation and functional application of polyethyleneimine/polyacrylonitrile composite fiber membrane
Objective The CO2 corrosion of metal-air batteries is extremely serious,which greatly limits the service life of the metal-air batteries.Existing researches generally add CO2 absorbers or O2 selective membranes to the cathodes,which indeed inhibit the CO2 corrosion to a certain extent,but have a negative impact on the electrochemical performance of the batteries.Therefore,there is an urgent need to explore a new method to inhibit cathode corrosion in metal-air batteries,which would not sacrifice the electrochemical performance of the battery and can effectively inhibit CO2 corrosion.Method Polyethyleneimine/polyacrylonitrile(PEI/PAN)precursor solutions with different PEI contents were prepared,and PEI/PAN composite fiber membranes were fabricated by electrospinning.The microstructure of the composite fiber membrane was characterized by scanning electron microscope and infrared spectrometer.The influences of different PEI contents on the CO2 adsorption performance of PEI/PAN composite fiber membranes were studied combining computer simulation and CO2 adsorption-desorption experiments.An aluminum-air battery with a PEI/PAN composite fiber membrane was prepared to verify the optimization effect of the composite fiber membrane on the discharge performance of the battery.Results PEI was successfully embedded into PAN fibers through electrospinning,and the surface was smooth and the layered fiber structure was evenly distributed.The computer simulation results showed that the PEI/PAN composite fiber membrane of system Ⅱ(50％PEI)illustrated excellent adsorption performance,and the CO2 adsorption-desorption experiment further confirmed the simulation results.When the pressure was 100 kPa,the adsorption capacity of PEI/PAN composite fiber membrane was 1.86 mmol/g.The experimental and simulation results agreed well to each other.Taking aluminum-air batteries as an example,aluminum-air batteries with PEI/PAN composite fiber membranes were assembled.Electrochemical test results showed that compared with conventional aluminum-air batteries,the cathode corrosion of aluminum-air batteries with PEI/PAN composite fiber membrane was significantly inhibited.The discharge time of the aluminum battery with PEI/PAN composite fiber membrane was 548 min,while the conventional aluminum-air battery was only 455 min.The discharge time of the battery with the composite fiber film was prolonged by 20.4％,and the specific capacity was increased by 19.5％,proving that the PEI/PAN composite fiber film could effectively inhibit the corrosion of the positive electrode and improve the electrochemical performance of the battery.Conclusion The PEI/PAN composite fiber membrane prepared has excellent adsorption properties,and its application in metal-air batteries can effectively inhibit the corrosion of CO2 on the air cathode.Adding PEI/PAN composite fiber membrane to the cathode of aluminum-air battery can significantly increase the specific capacity and prolong the discharge time of the battery.
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