Preparation Of Polyacrylonitrile Composite Piezoelectric Fiber Membrane And Its Performance In Self-charging System

Self-charging energy device can integrate nano generator and energy storage device into an independent energy unit,which makes energy conversion and energy storage into a simple process,and improves energy utilization and energy conversion efficiency.However,due to the structural characteristics of the self-charging battery,constrained by the problems of low efficiency of energy conversion and energy collection and insufficient storage capacity,the development of self-charging battery is still facing great challenges.This paper mainly focuses on the above problems and proposes solutions.The specific research contents are as follows:PAN composite fiber membrane was prepared by electrospinning,Through FTIR,XRD,mechanical properties and piezoelectric properties tests,the conclusion is as follows:the tensile strength of the composite film is higher than that of PAN,PVDF and commercial PP/PE film,and the tensile strength reaches 16.43mpa;the plane serrated content of pan can be increased by electrospinning In addition,the composite film has good piezoelectric stability and can still maintain high piezoelectric property under long-term compression vibration.The composite nanofiber membrane was used as piezoelectric separator to improve the performance of self-charging battery.The composite fiber membrane had a good thermal stability,with a liquid absorption rate of 250%,a porosity of 52%,and an ionic conductivity of 0.92ms/cm.The composite membrane was assembled into a lithium-ion battery.In the electrochemical test,the battery composed of the composite membrane showed higher charge discharge performance(129.56 mAh/g).From 0.2C to 5C,the battery still has a capacity retention rate of 55.35%,which can meet the basic requirements of battery separator.In the self-charging performance test,the voltage of the battery increases from 415.3mv to 476.7mv after 180s self-charging process under the pressure of 30N and frequency of 1.5Hz,and the voltage increases by 61.4mV and61.4Mv respectively under the constant current discharge condition of 1?A.After 130s,the voltage drops to 415.1mV and the storage capacity is 0.0361?Ah.Flexible structure is used to improve the performance of self-charging supercapacitor.A flexible self-charging super capacitor was prepared by using flexible carbon fabric material as electrode,polyvinyl alcohol/sulfuric acid as gel electrolyte and composite membrane as piezoelectric separator.The supercapacitor has excellent charge discharge characteristics and cyclic voltammetry curve,and can maintain a good specific capacitance(54 m F/cm~2)at high current density 20mA/cm~2).Moreover,after5000 charge and discharge processes,the good symmetry and linear relationship can be maintained,and the cycle life of the device is enhanced,which fully meets the requirements of supercapacitor.Under the external force of 30N and frequency of 1.5Hz,the voltage of flexible self-charging supercapacitor increases from 0V to 124.8mV in30s,and the device is discharged at constant current of 100?A,According to the calculation,the specific area capacitance of the device is 9.24 m F/cm~2,which is equivalent to 12.3%of the specific capacitance charged by external power supply.It is proved that flexible structure has higher energy utilization and energy conversion efficiency than stainless steel structure.