Synergistic Advancement of Molecular Design and Dual Encapsulation Technology for High‐Performance Room‐Temperature Barocaloric Refrigeration Materials

Abstract Plastic crystal neopentyl glycol (NPG) displays a colossal barocaloric effect akin to conventional refrigerants, rendering it as a highly promising solid‐state refrigerant. However, its practical application is restricted by its elevated phase transition temperature, inferior thermal conductivity, and weak mechanical response. Herein, a molecular design strategy is employed, wherein NPG molecules are substituted with trimethylolpropane (TMP) molecules, resulting in the successful synthesis of novel plastic crystals, designated as NPG_0.75TMP_0.25, with a phase change temperature of 283.7 K. To enhance the thermal conductivity, a dual encapsulation strategy is utilized to fabricate a highly oriented thermally conductive hybrid network composed of NPG_0.75TMP_0.25 and expanded graphite (EG) by using melt adsorption and pressure induction. The hybrid networks also significantly augment the mechanical properties of NPG_0.75TMP_0.25. The resulting composite barocaloric material exhibits a maximum entropy change of 223.8 J K⁻¹ kg⁻¹ achieved under pressure changes below 40 MPa and a thermal conductivity of 18.31 W m⁻¹ K⁻¹. Moreover, the composite exhibits high mechanical response and fatigue resistance. This study not only demonstrates the potential of composite barocaloric materials for practical applications but also significantly advances the engineering of barocaloric refrigeration.