Energy is constantly around people in its many forms – in the sunlight, warmth in the room and even the movements of the people themselves. All this energy is usually just “lost” to human civilization, but it can potentially be used to power mobile and wearable gadgets – from biometric sensors to smart clocks. Researchers from the University of Oulu (Finland) found a mineral with a perovskite crystal structure, the properties of which allow it to extract energy simultaneously from a variety of different sources.
Perovskites are a family of minerals, many of which have proved promising due to their ability to simultaneously extract energy of one or two types. Some of the representatives of this family, for example, may be good for converting solar energy into electricity. The other is better able to extract energy from changes in temperature and pressure, which can occur during the movement. They are called, respectively, pyroelectric and piezoelectric materials.
At times, of course, one type of energy as a source is not enough. A certain form of energy may not always be available – under cloudy weather or when a person does not move. Therefore, researchers have developed devices that can extract numerous forms of energy. But for such devices, different materials are required, which make them too bulky for use in compact devices.
Applied Physics Letters published the results of a study conducted by Yang Bai and his colleagues from the University of Oulu. The researchers studied a specific type of perovskite, called KBNNO, which is probably capable of extracting various forms of energy. Like all perovskites, KBNNO is a ferroelectric material filled with tiny electric dipoles, similar to small compass arrows in a magnet.
When a similar KBNNO ferroelectric material undergoes temperature changes, its dipoles are shifted and thus an electric current is induced. The electric charge also accumulates in accordance with the direction of the dipole moment. Deformation of the material leads to the fact that certain of its fragments attract or repel the charge, which again leads to the generation of current.
Previously, researchers have already studied the photovoltaic and general ferroelectric properties of KBNNO, but this study was conducted at 200 degrees below the freezing point, and they did not focus their attention on the properties of the material associated with temperatures and pressures. In the new study, notes Yang Bai, all these properties of the material, manifested at room temperature, were first evaluated.
Experiments have shown that while KBNNO is good for generating energy from heat and pressure, it is not as good as other perovskites. Perhaps the most impressive discovery of the researchers was the possibility of modifying the composition of KBNNO in order to improve its pyroelectric and piezoelectric properties. Thus, it is possible to “configure” all these properties and use them as efficiently as possible. Young Bai and his colleagues are exploring the possibility of improving the KBNNO material with the use of sodium.
Young Bai also said that next year he hopes to create a prototype of a device that extracts energy from various sources. The process of its production is simple, therefore commercialization of this technology can be carried out within several years after the researchers determine the best material.
According to Yang Bai, this technology can lead to acceleration of development in the Internet of things and smart cities, where energy-consuming sensors and devices can have constant access to energy.
Such material, most likely, can be used in battery of devices, increasing their energy efficiency and reducing the need for frequent charging. Someday, adds Yang Bai’s narrative, the user will never ever need to put his gadget on charge. Batteries of compact devices in the modern sense can generally remain in the past.
But the fact that a theoretical way is found to do without accumulators in gadgets does not mean either the rapid appearance of products using this technology, nor that technology will ever be realized.
Will someday wear portable devices and even smartphones without batteries, which are enough for the energy that is in the space around, but is lost, because there is no effective method of extracting it?
Based on sciencedaily.com