Flexible material will enable to transform magnetic fields into electricity
Scientists have created flexible composite material on the base of polymers and nanoparticles of cobalt ferrite, that is able to transform magnetic fields into electric tension. Such transformation can be used in creation of sensors, wireless devices and energy harvesting systems, that can work, using surrounding magnetic fields, not electricity. Researchers have found out that material function more effectively if you use nanoparticles, where part of cobalt ions is substituted for zinc (zinc-cobalt ferrite). Such composite generates tension, that exceeds characteristics of material with ferrite-cobalt nanoparticles three times and is comparable to some piezoelectric generators, that are used in wireless sensors. Results of the research are published in the journal Polymers.
In modern electronics there is a demand for such materials that can effectively transform different forms of energy into each other, for example, magnetic into electric one. Thus, for example, multiferroics—materials that combine magnetic and electric properties—are used in detectors, data storage systems and devices for energy harvesting. In contrast to ordinary electronic materials, that exclusively use electricity, multiferroics are able to react simultaneously on magnetic and electric fields, thanks to that you can create more compact and energy efficient devices on their base. However, majority of multiferroics are rigid and fragile, due to that they are not used in flexible electronics. That's why scientists are trying to create elastic analogues, that could retain high efficiency for energy transformation.
Researchers from Immanuel Kant Baltic Federal University (Kaliningrad) together with colleagues from Lomonosov Moscow State University (Moscow) and Nesmeyanov Institute of Organoelement compounds of Russian Academy of Sciences (Moscow) designed magnetoelectric composite, that consists from polymers and nanoparticles of ferrite cobalt.
As a base authors took silicone elastomer—soft and elastic polymer on the base of organosilicon compounds. They combined it with film from polyvinylidene fluoride – polymer that generates electric tension during deformation, for example, folding. Researchers added nanoparticles of ferrite cobalt to these compounds.
Moreover, scientists created samples with nanoparticles as a filler, where part of cobalt ions were substituted for zinc and nickel. This enabled to control magnetic properties of the composite. Thus, zinc decreases its resistance to demagnetization, and nickel increased magnetic susceptibility, by making material more sensible to weak magnetic fields.
Researchers placed obtained composites into alternating magnetic field, which strength was different in various space points. Under the influence of field, the silicone elastomer, that contained nanoparticles, bent and deformed the polyvinylidene fluoride layer. In its turn this layer generated electric tension. It turned out that the sample where particles with partial substitution of cobalt ions with zinc ions was used, transformed magnetic fields into electrical tension the most effectively. Its efficiency turned out to be thrice higher, than that of material, produced with particles of pure cobalt ferrite and was comparable to some piezoelectrical generators, that are used in wireless sensors.
"We showed that even small changes in the composition of nanoparticles can significantly increase magnetoelectrical effect. This is especially important for creation of compact and lightweight devices, for example, batteries for wearable electronics. In future such materials can form the base of energy efficient technologies that collect energy from surrounding electromagnetic fields. In future we are planning to produce a prototype and offer an alternative to existing analogues, a device that will be characterized by low cost, durability and light weght",—tells Valeria Rodionova, candidate of Physical and Mathematical sciences, director of Research&Education Center "Smart Materials and Biomedical Applications" of Immanuel Kant Baltic Federal University.
More information:
doi.org/10.3390/polym17091183
Provided by Immanuel Kant Baltic Federal University
