How sunburn inspired a new way to store energy

A chemistry professor has developed a high-density energy storage system inspired by the molecular damage of sunburn, achieving an energy density of 1.65 megajoules per kilogram [1]. Grace Han of the University of California, Santa Barbara, conceived the idea after reading about DNA photochemistry and noticing the intensity of sunlight in California [1]. She realized molecules that change shape under light, similar to DNA damaged by UV radiation, could store energy [1]. In a paper published in February, her team described a molecular solar thermal (Most) system where shape-shifting molecules, activated by 300-nanometer ultraviolet light, store energy [1]. When triggered with hydrochloric acid, the system rapidly released enough heat to boil a small amount of water [1]. 'When I actually saw the video and saw how quickly the entire solution was boiling, that was really remarkable,' Han said [1]. The recorded energy density of 1.65 megajoules per kilogram surpasses that of typical lithium-ion batteries [1]. However, the system relies on harsh UV light not abundant in sunlight and requires corrosive hydrochloric acid to release the energy, limitations Han acknowledges and aims to improve [1]. Researcher Kasper Moth-Poulsen noted the system's high energy density compared to prior efforts, highlighting Most technology's potential for long-term, emissions-free heat storage without combustion [1]. Challenges remain, including the need for thin material layers to allow light penetration and the complexity of liquid-based systems [1].