Multi-Stimuli-Responsive Aerogels Composed of Ag Nanoparticle-Coated Graphene Nanosheets for Energy Storage and Conversion

Phase change materials (PCMs) offer considerable possibilities in multienergy conversion and thermal energy storage, but the obvious drawbacks of melt leakage, fire risk, low thermal conductivity, and poor light absorption hinder their practical application. In this work, an excellent match of AgNPs and graphene nanosheets was achieved by constructing hybrid aerogels (GAA) through a hydrothermal reduction and thermal annealing process, followed by vacuum impregnation of paraffin wax (PW) to obtain shape-stable composite PCMs (PW-GAA). The 3D porous network connected by graphene nanosheets served as a dispersion carrier for AgNPs, ensuring efficient heat transfer pathways, effective thermal storage ability, and excellent solar-thermal and electro-thermal conversion capability of PW-GAA. Compared to pure PW, the melt leakage rate of PW-GAA3 is reduced to 2.56%, while the thermal stability and flame safety are improved. In addition, the PW-GAA3 can reach a solar-thermal conversion efficiency of 92.62% and an electro-thermal conversion efficiency of 95.19%. Furthermore, it achieves a solar-thermal-electric energy conversion output voltage of 200.5 mV. This work offers a promising approach for effective multienergy conversion and thermal energy storage utilization.