As solar energy becomes more common, one problem we begin to encounter more often is a lack of long-term storage. We don't always need energy right at the moment when it is produced. Solutions like exporting excess solar energy to the grid aren't always the most efficient and cost-effective solution (or even possible in remote locations). Innovation in energy storage is, therefore, becoming increasingly vital.

Scientists from Lancaster University produced encouraging results with a crystalline material, potentially getting us yet another step closer towards a sustainable future.

The remarkable material possesses characteristics that enable it to store energy for several months at room temperature, making it ideal for storing excess solar energy in the summer to be used in darker winter months or at remote houses/facilities located off the grid. The energy can be released in the form of heat whenever required.

The new material could prove useful in remote locations without access to the grid. - Image Credit: wildwave4 via Shutterstock / HDR tune by Universal-Sci

Another possible beneficial use case for the material could come in the form of a dilute coating that can be attached to exterior surfaces of buildings to store heat or used on car windscreens to remove ice on colder days in a more eco-friendly way.

The crystalline substance is composed of a type of so-called 'metal-organic framework' consisting of an arrangement of metal ions connected by carbon-based molecules to form three dimensional constructions. The framework was developed by a Japanese research team at an earlier date.

Subsequently, the Lancaster team came up with the idea to test the material for its energy storage capabilities by exposing it to UV light, causing the azobenzene molecules to change shape towards a strained configuration inside the pores of the metal-organic framework. This process saves injected energy in a manner akin to how a bent spring stores its potential energy.

The energy can be swiftly liberated when outside heat is applied to the material. The heat acts as a trigger to 'switch' its state. The released warmth can thereafter be applied to warm different materials.

It turns out that stored energy can be saved for at least 4 months but possibly even years. This is no small feat as contemporary materials created to fulfill the same function can only hold their energy for a few days, at most. A lot of this has to do with the fact that those materials have to be in a liquid state to be functional. The new metal-organic framework has an advantage as it functions as a chemically stable and easily containable solid.

Solar energy plays a crucial role in the worlds' switch to more sustainable forms of energy production - Image Credit: Jenson via Shutterstock / HDR tune by Universal-Sci

Joint Principal Investigator Dr. John Griffin stated in a press release that the new material acts similar to phase change materials used to provide heat in products like hand warmers. However, while hand warmers need to be heated to be recharged, this material captures "free" energy straight from the sun. Additionally, it has no moving or electronic parts, meaning that there is no energy loss when it gets stored or released.

The research team shared its aspiration to develop the material further so that it can store an even more considerable amount of energy. In addition, the crystalline materials show potential to be used for data storage utilizing its defined arrangement of photoswitches that could be switched on or off individually akin to how data storage works on optical media, but at a much smaller scale.

If you are interested in learning more about this study, be sure to check out the paper published in the science journal Chemistry of Materials listed below.

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