LAUSR

Salt hydrate phase change materials (PCMs) possess the challenge of supercooling, which must be addressed to allow more efficient energy storage and utilisation. In this work, cellulose nanofibril (CNF), a versatile biopolymer was used to support and disperse silver nanoparticles (AgNPs), and the synthesised CNF/AgNPs composite was used to improve the performance of sodium acetate trihydrate (SAT). Results showed that CNF dispersed the AgNPs uniformly and prevented their aggregation. Through the synergistic effect of 1% CNF/AgNPs and 2% sodium phosphate dibasic dodecahydrate, a low supercooling degree of 1.2 °C was achieved. Moreover, AgNPs were uniformly distributed in the prepared PCM composite. Differential scanning calorimetry results indicated that the prepared PCM@CNF/AgNPs 0.02 composite showed a similar melting point (57.4 °C) and enthalpy (269 kJ/kg), compared to those of pure SAT. Thermogravimetric analysis showed that the PCM composite did not lose all moisture until a heating temperature of 160 °C, showing improved thermal stability. The thermal conductivity of PCM@CNF/AgNPs 0.02 composite was 31.6% higher than that of SAT. The enthalpy of this composite decreased only around 2% after 100 melting/freezing cycles, showing satisfying thermal reliability. This composite can therefore be used to fabricate high-performance TES systems with negligible supercooling and improved thermal properties.