Core-ligand modulating core-shell coordination for stably supercooled phase change materials in long-term heat storage and release

Abstract

Hierarchically Core-shell coordinated metal-organic networks came out recently as a promising supercooled phase change material (SPCM) to achieve mutually stable energy storage and controllable release for long-term energy storage and release.However, this new material system needs further developments especially regarding their supercooling stability for the high-enthalpy composition. Here, we report a Mnacetamidomethanol@erythritol (MA@Er) core-shell SPCM at high erythritol loads relying on the core ligand modulation, achieving both high supercooling stability and controllable crystallization simultaneously. As revealed, the hydroxylic group of acetamidomethanol in the core-shell interactions with erythritols leads to over 5 times higher thermodynamic energy barrier than the currently reported counterparts, resulting in only 7.8% loss of enthalpy after 1000 successive thermal charge-discharge cycles.MA@Er with 161 kJ/kg enthalpy can release the latent heat to attain a temperature peak of 71.7°C shortly after triggering by a small shear stress of 8 Pa. Moreover, its thermal energy utilization efficiency reaches 86.3% by consuming low-grade waste heat.MA@Er core-shell SPCMs demonstrate a great potential in practical utilization of lowgrade thermal energy in the long-term mode.