Bio-based MXene hybrid aerogel/paraffin composite phase change materials with superior photo and electrical responses toward solar thermal energy storage

Green, stable, and high-performance phase change materials with photothermal/electrothermal capabilities are crucial for solar thermal utilization. In this paper, biomass cellulose nanocrystals (CNCs), konjac glucomannan (KGM), MXene (a two-dimensional material), and AgNO3 were first mixed through a simple and fast physical process and then subject to directional freeze-drying and thermal annealing successively. The resulting lightweight porous carbon aerogels further adsorbed paraffin to yield a composite phase change material PMCKA. PMCKA had a high loading rate (95.16%), high enthalpy (231.38 J/g), exceptional conductivity (147.5 S/m), and remarkable cycle stability. Moreover, the photothermal and electrothermal conversion efficiencies of PMCKA might reach up to 97.45% and 98.89%, respectively. This finding demonstrates superior photothermal and electrothermal conversion performance of PMCKA in solar energy storage. Therefore, PMCKA can probably be widely applied to solar thermal conversion, industrial waste heat recovery, and thermal management of electronic equipment.