Preparation and properties of orientation reinforced CO2 corrosion resistant fiber membrane
Objective CO2 corrosion of the cathode in flexible metal-air batteries severely reduces its electrochemical performance and greatly hinders the further development of flexible metal-air batteries.Existing research shows that the amino functional group in PEI has strong adsorption capacity for CO2.By increasing the orientation of the fiber membrane,the specific surface area and pore volume of the fiber membrane can be increased,thereby enhancing the adsorption capacity of the fiber membrane.A high degree of orientation can also enhance the mechanical properties of the membrane to a certain extent.However,there are few studies on cathode separators for flexible metal-air batteries offering both excellent CO2 adsorption capacity and good mechanical properties.As such,this study aims to use electrospinning technology to prepare highly oriented Polyethyleneimine(PEI)/polyacryloni-trile(PAN)composite fiber membrane by adjusting the drum speed,and to characterize its physical properties,mechanical properties and CO2 adsorption properties.Method Four different groups of PEI/PAN composite fiber membranes were prepared at the drum rotation speeds of 500,1 000,1 500 and 2 000 r/min respectively.Fourier transform infrared spectroscopy,X-ray diffractometer,Scanning electron microscopy,and a flexible electronic comprehensive test platform were used to characterize the physical properties and mechanical properties of the composite fiber membranes.The CO2 adsorption performance of the composite fiber membranes was characterized by a specific surface area and pore size analyzer and a simultaneous thermal analyzer,and the influence of orientation on the CO2 adsorption capacity and mechanical properties of the PEI/PAN composite fiber membrane was explored.Results The results of infrared spectroscopy and scanning electron microscopy show that the PEI/PAN composite fiber membrane was successfully prepared by electrospinning,and as the drum speed increases,the fiber diameter decreases.The rotation speed of the drum greatly affected the orientation of the fibers.When the rotation speed was 1 500 r/min,the orientation of the fibers seemed the best.The high degree of orientation obtained by increasing the rotation speed of the drum can obtain a larger specific surface area and pore volume of the PEI/PAN composite fiber membrane,thus improving its ability to adsorb CO2.This is mainly due to the smaller fiber diameter and the larger gap formed by fiber stacking between the non-oriented and oriented directions.The increase in fiber orientation also enhances the crystallinity of fibers,which greatly affects their mechanical properties.High orientation caused increase the tensile breaking strength and Young's modulus of the fibers in the longitudinal direction.This is mainly because the nanofibers arew able to withstand greater tensile stress when they are aligned.Conclusion The PEI/PAN composite fiber membrane prepared by electrospinning at 1 500 r/min has excellent orientation.Compared with the randomly oriented composite fiber membrane prepared by electrospinning at 500 r/min,the CO2 adsorption capacity of the prepared membrane is increased by 62.06%,the longitudinal tensile breaking strength is enhanced by 178.57%,and the Young's modulus is enhanced by 245.3%.The research reported in this article provides a reference for the preparation of cathode anti-CO2 corrosion membranes for flexible metal-air batteries.
oriented nanofiber membraneelectrospinningCO2 adsorptionmechanical propertybattery diaphragm material