Synergistic suppression of supercooling and thermal performance enhancement of sodium acetate trihydrate using BNNS/Al₂O₃ composite nucleating agents

Sodium acetate trihydrate (SAT) possesses a high latent heat of phase transition; however, its high degree of supercooling, low thermal conductivity, and susceptibility to phase separation limit its practical applications. This study proposes an XG-stabilized BNNS/Al 2 O 3 composite nucleation modification strategy that suppresses SAT supercooling through the combined regulation of Al 2 O 3 particles and two-dimensional BNNS, while utilizing BNNS to improve heat transfer performance. Experimental results show that 2 wt% XG effectively suppresses phase separation, 0.5 wt% Al 2 O 3 reduces the supercooling to 5.53 ℃, and BNNS further lowers the supercooling to 0.65 ℃ while increasing the thermal conductivity to 1.543 W·m − 1 ·K − 1 .Furthermore, after 100 thermal cycles, the composite exhibited good thermal energy retention capacity. This composite achieves a good overall balance between supercooling suppression, thermal energy storage density, and thermal conductivity, demonstrating application potential in the fields of low-to-medium-temperature thermal energy storage and thermal management.