Colossal Barocaloric Effect in Encapsulated Solid‐Liquid Phase Change Materials

Abstract Barocaloric cooling as an emerging cooling technology offers an eco‐friendly alternative to traditional vapor compression refrigeration. Research on barocaloric materials primarily concentrates on solid–solid phase change materials (PCMs), among which plastic crystals exhibit colossal barocaloric effect. Solid‐liquid PCMs such as paraffin also exhibit giant barocaloric effect, however, their potential is often overshadowed by leakage issues. In this work, a strategy is demonstrated by encapsulating solid‐liquid PCMs into porous carbon matrixes to generate a large family of colossal barocaloric materials. In practice, by orthogonally combining paraffins with encapsulation matrixes like graphene foam, carbon nanotube foam, and carbon foam, it can be obtained composites that work without leakage issues. The significant advantage is their colossal barocaloric effect with the highest entropy value up to 570 J K −1 kg −1 in paraffin‐20@graphene foam. Moreover, the composites possess thermal conductivity up to 89.9 W m −1 K −1 in paraffin‐20@carbon foam, and tunable working temperature in the range of 270—330 K. Most importantly, this strategy, demonstrated with 5 solid‐liquid PCMs and 3 encapsulation matrixes in this work, is just the beginning. Further exploration with more materials can develop a huge family of encapsulated solid‐liquid PCMs with colossal barocaloric performance for modern cooling technology.