Supramolecular Phase Change Materials for Spatiotemporally Thermal Energy Utilization

Phase change materials (PCMs) are promising heat storage media to solve the intermittency and instability of renewable energy utilization. However, due to the spontaneous crystallization behavior and the accompanied release of latent heat upon cooling, the absorbed thermal energy can not be well stored at room temperature, which severely limits the applicability of PCMs in thermal energy storage. Herein, the long-term storage as well as switchable and controllable release of thermal energy using activated perethylated pillar[5]arene EtP5 (EtP5α) is reported for the first time. Through activation at 393 K, EtP5α can store thermal energy in the supercooled state at room temperature and release thermal energy by triggering cold crystallization at 370 K. High thermal energy storage capacity can be maintained for 20 thermal cycles and more than 365 days at room temperature, which is the PCMs that can store thermal energy for the longest time at room temperature.