Molecular Solar Thermal Storage Enhanced by Hyperbranched Structures

Abstract

Molecular solar thermal fuels have received more and more attention recently to meet the ever‐increasing global energy demands. However, molecular solar fuels are still impeded by low storage energy and short half‐life. Herein, novel molecular solar fuels are prepared from azobenzenes grafted on graphene with layer‐by‐layer dendritic hyperbranched structures. The storage performances of photoactive molecular fuels can be increased significantly via layer‐by‐layer dendritic amplification. The energy density of three‐layer hyperbranched fuels can reach up to 104 W h kg−1 (374 J g−1), which is more than three times that of pristine azobenzenes (32 W h kg−1 or 115 J g−1). Moreover, the storage half life of three‐layer hyperbranched fuels can reach 80 h, which is much longer than that of pristine azobenzenes (2.5 h). This strategy of fabricating the azobenzene–graphene hybrids with hyperbranched structures paves a new way for the development of high‐performance molecular solar thermal fuels.