The new material is designed to store heat from the sun during the day in form of thermal battery, which can release heat when needed.

The researchers said that the new system combines phase change material (PCM) with molecular switches that change shape when exposed to light.

MIT said: “When integrated into the PCM, the phase-change temperature of the hybrid material can be adjusted with light, allowing the thermal energy of the phase change to be maintained even well below the melting point of the original material.”

Capable of storing around 200 joules of energy per gram, the system can withstand a temperature change of around 10 degrees Celsius (18 degrees Fahrenheit).

MIT professor Jeffrey Grossma said: “Our interest in this work was to show a proof of concept, but we believe there is a lot of potential for using light-activated materials to hijack the thermal storage properties of phase change materials.”

Additionally, the system can retain heat for 10 hours, unlike similar device which have capacity to store heat for few minutes.

Commenting on the research work, University of California at Berkeley materials science and engineering professor Junqiao Wu said: “This is highly creative research, where the key is that the scientists combine a thermally driven phase-change material with a photoswitching molecule, to build an energy barrier to stabilize the thermal energy storage.”

The work is backed by the Tata Center for Technology and Design within MIT’s Energy Initiative.


Image: MIT researcher handling a new chemical composite designed to store thermal energy. Photo: courtesy of Melanie Gonick/Massachusetts Institute of Technology (MIT).