Sung Bum Kang1,Youngmun Lee1,Daniel Hsieh1,Wuchen Fu1,Ho Chan Chang1,Jay Taylor1,Mayur Prabhudesai1,Nenad Miljkovic1,Sanjiv Sinha1,Paul Braun1
University of Illinois at Urbana-Champaign1
Sung Bum Kang1,Youngmun Lee1,Daniel Hsieh1,Wuchen Fu1,Ho Chan Chang1,Jay Taylor1,Mayur Prabhudesai1,Nenad Miljkovic1,Sanjiv Sinha1,Paul Braun1
University of Illinois at Urbana-Champaign1
Phase change materials (PCM) are a promising candidate for thermal energy storage in building infrastructure, enabling grid-integrated peak load shaving by utilizing energy production in off-peak hours. Glauber’s salt (Na<sub>2</sub>SO<sub>4.</sub>10H<sub>2</sub>O, Sodium sulfate hydrate) are highly attractive due to their high energy storage capacity and low cost but Glauber’s salt suffers from long-standing challenges including high supercooling ( > 15<sup>o</sup>C) and low thermal cyclic stability, which is a major setback for practical building-scale energy storage applications. Here, we developed a unique ionic molecular nucleating agent for Glauber’s salt which reduced the supercooling temperature to less than 5<sup>o</sup>C. By combining this nucleated SSD with a polymer, phase segregation of salt hydrate for over 100 thermal cycles without degradation was achieved. Key was that the polymer confined the SSD crystals, preventing phase separation. In addition, we applied our stable Glauber’s salt composite in a miniatured building model and demonstrate that our PCM composite can be utilized for real-world building infrastructure.