Fatty acid eutectics embedded in guar gum/graphene oxide/boron nitride carbon aerogels for highly efficient thermal energy storage and improved photothermal conversion efficiency

Carbon aerogels with low density, high compressibility and fatigue resistance, are of great interest for the encapsulation of phase change materials (PCMs) to resolve their leakage and low thermal conductivity issues, thus providing exciting potential for thermal management and energy storage. In this work, we successfully fabricated interconnected carbon aerogels with superior mechanical performance from graphene oxide (GO), thermally conductive hexagonal boron nitride (BN), and green biomass guar gum (GG). The GG with long soft molecular chains stabilized the porous structures of the carbon aerogels through hydrogen bonding. GG also maintained the even dispersion of BN in the carbon skeleton, forming a connected thermal conductive network. Furthermore, the stearic acid (SA)-capric acid (CA) binary eutectic PCMs were successfully capsulated in the porous structures of the obtained GG/GO/BN carbon aerogels to fabricate composite PCMs with high thermal conductivity and good shape stability, which overcoming the limitations of single PCMs and expanding their thermal energy storage applications. The composite PCMs exhibited an excellent energy storage capacity of 161.63 J/g with almost no change after 100 thermal cycles. In addition, the thermal conductivity of the composite PCMs increased to 0.6061 W∙m−1∙K−1, which was nearly three times that of SA-CA, and the photothermal conversion efficiency of the composite PCMs reached 92.56 %.