Solar thermal fuels can harvest and store solar energy through the conversion of molecular conformation in a closed circulation system and release energy in the form of heat on demand. In this paper, a series of isotactic azobenzene-based polyethers (azopolyethers) with main-chain chirality were synthesized via highly enantioselective resolution polymerization of racemic azobenzene-containing epoxides. The thermal properties, photoisomerization, and energy-storage properties of these resultant azopolyethers as a new generation of solar thermal fuels were investigated in detail. These isotactic-enriched azopolyethers with trans-azobenzene moieties were found to be semicrystalline materials with melting temperatures in the range of 230-259 ℃ and crystallization temperature within the scope of 197-219 ℃. The azobenzene groups in the polyethers exhibited reversible trans-to-cis and cis-to-trans photoisomerization upon irradiation with light. Due to the crystallization characteristic of isotactic polyethers, their energy storage densities are significantly higher than that of the corresponding amorphous polyethers, and the maximum energy storage density is up to 193.7 J/g. This provides a new idea for the research of polymer energy storage materials.