Cellulose nanofibril/carbon nanotube composite foam-stabilized paraffin phase change material for thermal energy storage and conversion

The leakage and low thermal conductivity of paraffin phase change material (PCM) must be addressed to achieve a more efficient energy storage process. In this study, cellulose nanofibril (CNF) foams were prepared as the porous support of paraffin to prevent its leakage, and multiwalled carbon nanotubes (CNTs) were incorporated in the foams to improve heat transfer performance. Treatment of CNF with methyltrimethoxysilane improved compatibility between the foams and paraffin. The prepared highly porous (porosity >96%) foams had paraffin absorption capacities exceeding 90%. The form-stable PCM composites displayed negligible paraffin leakage and had a compact structure. The prepared PCM composites had enhanced heat transfer performance, reasonable phase change properties and thermal stabilities. The enthalpy of the SCNF/CNT50-Pw PCM composite decreased by 6% after 100 melting/freezing cycles. Compared with pristine paraffin, the PCM composites exhibited superior form-stabilities and improved thermal properties, which suggested application in a solar-thermalelectricity energy harvesting and conversion system.

Automated summary

The study addresses the leakage and low thermal conductivity issues of paraffin phase change material (PCM) by preparing cellulose nanofibril (CNF) foams and incorporating multiwalled carbon nanotubes (CNTs). The prepared PCM composites demonstrate high paraffin absorption capacities, negligible leakage, improved heat transfer performance, and enhanced thermal stabilities, making them suitable for solar-thermal electricity energy harvesting and conversion systems.