Comprehensive Evaluation of Barium Hydroxide Octahydrate for Reliable Thermal Energy Storage: Supercooling Suppression and Corrosion Compatibility

ABSTRACT This study presents a comprehensive experimental evaluation of the reliability and thermal stability of a barium hydroxide octahydrate (BHO)‐based phase change material (PCM) with a phase change temperature of 78°C, focusing on supercooling suppression and corrosion resistance. Eight nucleating agents were added to PCM samples at varying mass fractions to evaluate their efficacy for supercooling suppression, which was statistically evaluated across 30 thermal cycles. Corrosivity was additionally assessed through long‐term immersion tests using five metals commonly used in thermal energy storage applications. As a result, among the nucleating agents, strontium hydroxide octahydrate (1.0 wt%) exhibited the most effective and consistent suppression capability, achieving a normalized weighted score of 0.996. SUS304 and SUS316 showed negligible mass loss (< 0.1%) and minimal surface degradation. In addition, DSC analysis revealed that contact with reactive metals reduced latent heat and altered melting behavior, indicating impaired thermal performance. It was concluded that strontium hydroxide octahydrate combined with SUS304 or SUS316 provides a promising and durable solution for thermally stable latent heat storage applications of BHO.