Transparent polymer film stores sunlight and expends it as heat

A new transparent polymer film that stores sunlight and outputs it as energy at a later time has been developed by MIT. According to the group of researchers at MIT, the film could be applied to many surfaces, for example, clothing, siding or windows. The heat could be released when needed. Currently, the sun’s energy is stored and later recovered as electricity, but this new material has the possibility of providing a high-efficient method for storing the sun’s energy. The storing process is doing through a chemical reaction. It was found by Jeffrey Grossman, an MIT professor, postdoc David Zhitomirsky and Eugene Cho, a graduate student. According to a paper in the journal of Advanced Energy Materials, to obtain a long-term stable storage of heat from the sun, it has to be done through a chemical change versus storing the heat itself. The storage system would take advantage of a stable molecular configuration. The energy would then released by a small amount of light or electrical heat. The trick is to find a molecule that will remain stable in two different configurations. At first blush, exposure to sunlight would take the energy of the light and jump start the molecules into a “charged” state where they could remain for long periods of time. Those molecules could then be triggered by very specific stimuli, pushing them back into their original shape and giving off heat as it does. Solar thermal fuels (STF) as they’re called, aren’t new and have been developed before. Grossman and his team have played a part in that process, but those efforts had “had limited utility in solid-state applications.” The reason for that is that they were designed to be used in liquid solutions as opposed to solid state films. Unlike the old approach, this is based on solid-state materials. To be more specific, inexpensive materials. In order to make this polymer film, it’ll take a two-step process. The heat-storing material could be made into a thin film and could be “incorporated into many different materials.” Those materials could then be made into thin film that could be applied to many different things, from thawing windshields to heating up food in bowls. Of course, the film is a work in progress, and Grossman’s team is working on improving the film’s properties. In its current form, it has a slight yellowish tinge and researchers are trying to make the material more transparent. Also, researchers are trying to boost the energy expenditure to 20 degrees Celsius above the surrounding temperature. Currently, it can only push 10 degrees above the surrounding temperature. University of Toronto professor Ted Sargent, who’s not a part of the research, is enthusiastic about the research. As he put it: “This work presents an exciting avenue for simultaneous energy harvesting and storage within a single material. The approach is innovative and distinctive. The research is a major advance towards the practical application of solid-state energy-storage/heat-release materials from both a scientific and engineering point of view.”