Room-Temperature Colossal Elastocaloric Effects in Three-Dimensional Graphene Architectures: An Atomistic Study

摘要

Solid-state cooling exploits the thermal response of caloric materials whensubjected to external physical fields and represents a promising alternativeto conventional refrigeration technologies. However, existing caloric materialsare often limited by relatively small caloric response and hysteresisissues rooted in first-order structural transitions. Here, colossal and reversibleelastocaloric effects near room temperature in superelastic graphenearchitectures are predicted by thermodynamic analysis and atomistic calculations.The estimated adiabatic temperature change can reach a value of 155 Kunder a compressive stress of 0.7 GPa in a wide temperature range of around300 K, yielding outstanding elastocaloric strength and efficiency. More uniqueis that both cooling and warming can be realized in the materials by applyingtensile and compressive strains to host conventional and inverse elastocaloriceffects, respectively, with almost no fatigue behavior and hysteresis effect.Such unprecedented elastocaloric performance results from a strain-inducedlarge change in configurational entropy in the graphene architectures. Theseeffects are potentially extendable to other superelastic nanomaterials andhence suggest new material settings for developing high-performance solidstaterefrigerants.