Graphene Aerogels Embedded with Boron Nitride Nanoparticles for Solar Energy Storage and Flame-Retardant Materials

Phase change energy storage technology provides a viable option for the use of solar energy; however, its potential shortcomings such as low thermal conductivity, phase change leakage, and fire hazards have led to defective applications. In this paper, graphene/boron nitride (GB) aerogels with dual thermal conductivity networks are constructed using boron nitride precursors BM (boric acid and melamine) and graphene oxide through a self-assembly method during reduction and calcination. The GB aerogels are then vacuum impregnated with paraffin wax (PW) to prepare PW–GB composite phase change materials (PCMs). The results show that the dual-layer network structure ensures that the PW–G4B2 composites have outstanding latent efficiency (96.7%) as well as a low leakage rate of 3.0%. Thanks to the highly thermally conductive BN fiber attachment, the thermal conductivity of PW–GB reaches 0.4108 W/(m·K), which is 81.5% higher than that of pure PW. Meanwhile, its photothermal conversion efficiency reaches 78.99% at 100 mW/cm2 optical density, showing great potential for thermal management in photothermal conversion applications. Moreover, the synergistic barrier effect of BN fibers with excellent thermal stability and graphene nanosheets results in significant improvements in the thermal stability and flame-retardant performance.