Third-generation ultralong-term latent heat storage glass based on a sugar alcohol mixture.

Long-term thermal storage can decarbonize heat utilization by resolving mismatches between heat supply and demand. However, common heat storage materials cannot store energy for long periods. Here, we report an ultralong-term latent heat storage "glass" based on a ternary eutectic sugar alcohol mixture. The as-prepared material exhibits a solid-liquid phase change and glass transition at 423 and 289 K, respectively, with heat release via cold crystallization at 346 K. Remarkably, the glass transition temperature increases to 313 K after aging at ambient temperature for 12 hours due to structural relaxation. This phase change material (PCM) conserves the latent heat of fusion at 423 K for at least 180 days in the glass state at ambient temperature. These results establish a third-generation latent heat storage mode, retaining the charged state as a kinetically arrested amorphous solid and thereby fundamentally shifting the stability criterion from supercooled-liquid nucleation suppression to glass-transition and structural-relaxation kinetics.