Thermally conductive composites with adjustable phase change temperature for efficient thermal management

Inorganic hydrated salt phase change materials (PCMs) featuring non flammability, high energy storage density, and low cost can effectively improve energy utilization efficiency and reduce the mismatch between energy supply and demand. However, the phase change temperature of inorganic hydrated salts with high energy storage density is usually too high or too low, significantly limiting their thermal management applications. In this work, thermally conductive inorganic hydrated salt PCMs with high energy storage density and adjustable phase change temperature are developed by integrating hydrogen bonds and ion interactions. The supercooling, phase separation and cyclic stability of sodium sulfate decahydrate (SSD) are improved by introducing nucleating agents and nano-structured bacterial cellulose (BC). A controllable adjustment of phase change temperature in the range of 30-37 degrees C is achieved by compounding a thermally conductive temperature regulator. Furthermore, the addition of a small amount of boron nitride (BN) improves the thermal conductivity of shape-stabilized SSD, giving rise to a superior thermal conductivity of up to 1.55 W m- 1 K-1. The resulting thermally conductive composite PCMs with opportune phase change temperature, high energy storage density and enhanced cyclic stability are capable of achieving effective thermal management of batteries and buildings.