Investigation On The Magnetoelectric Energy Conversion Properties Of Flexible Nanocomposite

With the rapid development of smart grids and the advances in intellectualization of electronic devices,efficient utilization of power energy,real-time monitoring of power systems,and the integration and decarbonization of power equipment have become important directions for the development of the power industry.Smart and efficient sensors are the core module for condition monitoring in power systems,ensuring the safe and stable operation of power systems.Therefore,the core of the advance of a perception layer in the energy internet is the development of efficient and intelligent power sensors,and it is also a key to realize automated control and ensuring high-quality power supply.The core functional material plays an important role in improving the sensing performance of new sensors.The development and application of new sensors based on high-performance functional materials are also an essential part of the transformation from traditional to modern power equipment.In this paper,the magnetoelectric composite of poly(vinylidene fluoride-co-trifluoroethylene)copolymer(PVDF-TrFE)is investigated by doping with superparamagnetic Fe3O4 nanoparticles.The impact of Fe3O4 doping on the magnetoelectric conversion efficiency and the magnetoelectric coupling effect under external magnetic field are explored.The results provide reference values for the development and application of new intelligent magnetoelectric sensors in future power systems.In this paper,PVDF-TrFE magnetoelectric composite and PVDF-TrFE/Fe3O4 composite were prepared using a spin-coating method.Based on the magnetoelectric coupling mechanism of the Lorentz force and piezoelectric effect,a layered magnetoelectric coupling structure of Au electrode/electromechanical coupling/Au electrode was designed,and a theoretical model of the magnetoelectric coupling was established.Furthermore,a magnetoelectric effect measurement system was set up to analyze the magnetoelectric coupling properties of the magnetoelcctric composite.Furthermore,the influence of Fe3O4 nanoparticles on the electrical properties of the polymer was explored through microscopic characterization techniques,and the change of magnetoelectric voltage for pure PVDF-TrFE and magnetoelectric composite doped with Fe3O4 nanoparticles were measured.Molecular dynamics simulations were also performed to investigate the enhancement of the magnetoelectric effect and the internal stress of the magnetoelectric composite induced by superparamagnetic nanoparticles.The results showed that PVDF-TrFE/Fe3O4 composite doped with a concentration of 0.5wt%exhibited the best performance with piezoelectric coefficient of 18pC/N at a polarization temperature of 110℃.Doping with Fe3O4 nanoparticles can increase the β-crystal crystallinity and dipole orientation of PVDF-TrFE thin film,thereby the magnetoelectric coupling performance of the magnetoelectric composite was enhanced.During the investigation of the factors affecting magnetoelectric energy conversion,the impact of alternating and direct magnetic fields on the output magnetoelectric voltage was observed.Additionally,the effect of increased electrical conductivity of the metal electrode layer on the enhancement of the magnetoelectric effect was explored.Moreover,the magnetoelectric voltage coefficient of PVDF-TrFE/Fe3O4 composite doped with superparamagnetic nanoparticles under resonance mode was 8.97mV/(cm Oe),which was 17.5%higher than that of the pure PVDF-TrFE composite.The mechanical characteristic calculated by simulation showed that all the Young’s modulus,shear modulus,and bulk modulus of PVDFTrFE/Fe3O4 composite were smaller than those of PVDF-TrFE,which verified that doping Fe3O4 nanoparticles increased the strain of the magnetoelectric composite under an external magnetic field and the charge density of the electromechanical coupling layer.Furthermore,the magnetoelectric energy conversion efficiency was improved.This paper focuses on the effect of doping modification on the magnetoelectric coupling properties of PVDF-TrFE/Fe3O4 composite,establishing an energy conversion theoretical model to explore the magnetoelectric energy conversion mechanism.The influence of superparamagnetic nanoparticles on the magnetoelectric effect of the magnetoelectric composite is further analyzed by combining microscopic characterization with macroscopic measurement.The conclusions of this research provide theoretical basis and reference for the real-time monitoring of intelligent electrical equipment and the development of advanced magnetoelectric sensors.