Abstract
As renewable energy technologies continue to advance, supercooled phase change materials (PCMs) are emerging as a promising solution for long-term thermal energy storage (TES), gaining significant attention from both researchers and industry for their potential to enhance energy efficiency. In our previous study, a supercooled PCMs system that blended erythritol (ET) and d-mannitol (DM) was shown to exhibit high latent heat but could not achieve long-term thermal storage stability. To extend the thermal storage duration of the previous DM/ET (DE) material, it served as a foundation that was integrated with sodium alginate (SA) to produce novel SA/DE PCMs. Experimental results demonstrated that the subject SA/DE PCMs were stable after 3 months of room-temperature storage (approximately 10-30 °C) attributed to intermolecular hydrogen bonding between hydroxyl groups of SA and DE. When the SA content was 3 wt %, the mixture exhibited a maximum cold-crystallization enthalpy (ΔH (cc)) of 199.0 J/g, which was approximately 97.0% of pure DE's ΔH (cc) value. Furthermore, this material exhibited excellent cyclic stability, and the stored latent heat could be controllably released through different triggers. This study opens new pathways for long-term thermal energy storage and dispatchable utilization, showing great promise for renewable energy integration and carbon-neutral technologies.