Optimizing Polarization of Magnetoelectric Composite Films for Energy Harvesting Applications
Faculty Mentor Information
Dr. Zhangxian (Dan) Deng, Boise State University; and Matt Zuzelski, Boise State University
Presentation Date
7-16-2026
Abstract
Magnetoelectric (ME) composites combine a piezoelectric material with a magnetostrictive material to convert both mechanical and magnetic energy into electrical energy. This coupling effect enables self-powered operation, removing the need for batteries, which require regular maintenance or replacement and are often impractical in hard to access environments. As a result, ME composites are well suited for flexible devices spanning applications from self-powered structural health monitoring sensors on spacecraft, to biomedical energy harvesting in wearable sensors and implantable medical devices. However, the performance of ME composites depends heavily on how effectively they are fabricated, from the annealing stage through polarization. This research addresses the fabrication and polarization of ME composite films, with a specific focus on identifying the poling method that most effectively enhances piezoelectric performance. To investigate this, poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and cobalt ferrite (CoFe₂O₄) composite films were fabricated and polarized to optimize their piezoelectric response. In this system, P(VDF-TrFE) serves as the piezoelectric material layer, generating an electric charge in response to mechanical stress. While CoFe₂O₄ serves as the magnetostrictive material layer, changing shape in response to an applied magnetic field. When combined, strain from the CoFe₂O₄ layer transfers to the P(VDF-TrFE) layer, inducing an electric charge, which is the mechanism behind the magnetoelectric coupling that allow these composites to convert magnetic energy into usable electrical energy. Using direct ink writing (DIW), 15 wt% double layered films were printed and tested across a range of annealing temperatures to find and promote the correct electroactive β-phase of P(VDF-TrFE), necessary for strong piezoelectric behavior. The maximum annealing temperature identified for developing the correct crystal structure was 120°C, which produced smooth, flexible films, while higher temperatures caused cracking and structural degradation. X-ray diffraction (XRD) analysis confirmed appropriate crystallinity in the 120°C film. The next stage of this research is polarization of the optimized films using corona and contact poling methods, with resulting polarization efficiency compared via the d33 piezoelectric coefficient. It is possible that the lower annealing temperature required to prevent cracking of the film may result in a reduced piezoelectric response compared to films annealed at higher temperatures, representing a potential trade-off between structural integrity and performance, though this remains to be confirmed through testing. Film thickness measurements are currently underway to calculate the appropriate poling electric field, ensuring the films are neither over nor under polarized. This work aims to identify optimal poling parameters for ME composite films, contributing to broader efforts to enable flexible, self-powered materials for next generation energy harvesting in sensors for structural health monitoring and medical device applications.
Optimizing Polarization of Magnetoelectric Composite Films for Energy Harvesting Applications
Magnetoelectric (ME) composites combine a piezoelectric material with a magnetostrictive material to convert both mechanical and magnetic energy into electrical energy. This coupling effect enables self-powered operation, removing the need for batteries, which require regular maintenance or replacement and are often impractical in hard to access environments. As a result, ME composites are well suited for flexible devices spanning applications from self-powered structural health monitoring sensors on spacecraft, to biomedical energy harvesting in wearable sensors and implantable medical devices. However, the performance of ME composites depends heavily on how effectively they are fabricated, from the annealing stage through polarization. This research addresses the fabrication and polarization of ME composite films, with a specific focus on identifying the poling method that most effectively enhances piezoelectric performance. To investigate this, poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and cobalt ferrite (CoFe₂O₄) composite films were fabricated and polarized to optimize their piezoelectric response. In this system, P(VDF-TrFE) serves as the piezoelectric material layer, generating an electric charge in response to mechanical stress. While CoFe₂O₄ serves as the magnetostrictive material layer, changing shape in response to an applied magnetic field. When combined, strain from the CoFe₂O₄ layer transfers to the P(VDF-TrFE) layer, inducing an electric charge, which is the mechanism behind the magnetoelectric coupling that allow these composites to convert magnetic energy into usable electrical energy. Using direct ink writing (DIW), 15 wt% double layered films were printed and tested across a range of annealing temperatures to find and promote the correct electroactive β-phase of P(VDF-TrFE), necessary for strong piezoelectric behavior. The maximum annealing temperature identified for developing the correct crystal structure was 120°C, which produced smooth, flexible films, while higher temperatures caused cracking and structural degradation. X-ray diffraction (XRD) analysis confirmed appropriate crystallinity in the 120°C film. The next stage of this research is polarization of the optimized films using corona and contact poling methods, with resulting polarization efficiency compared via the d33 piezoelectric coefficient. It is possible that the lower annealing temperature required to prevent cracking of the film may result in a reduced piezoelectric response compared to films annealed at higher temperatures, representing a potential trade-off between structural integrity and performance, though this remains to be confirmed through testing. Film thickness measurements are currently underway to calculate the appropriate poling electric field, ensuring the films are neither over nor under polarized. This work aims to identify optimal poling parameters for ME composite films, contributing to broader efforts to enable flexible, self-powered materials for next generation energy harvesting in sensors for structural health monitoring and medical device applications.