From Low-Energy Methanol to Gasoline-Level Fuel: Adamantane-Enhanced Gel Fuels with Shear-Thinning Pumpability

Methanol is a low-carbon fuel and energy carrier, but its low volumetric energy density limits its application in volume-constrained systems. Here, methanol-adamantane gel fuels are developed to increase volumetric energy density while maintaining pumpable handling. All formulations form self-standing gels at room temperature. Adamantane induces a dual network consisting of a gelator fibrillar scaffold and an adamantane-rich crystalline skeleton, which strengthens solvent confinement and suppresses segregation. The measured densities and cone calorimetry outputs exceed linear mixing predictions. At a 5:5 adamantane-to-methanol volume ratio, the gel reaches 36.01 MJ/L, which is 104.54% higher than neat methanol and comparable to gasoline. Microscopic analysis reveals porous, interconnected frameworks that immobilize methanol and anchor solid domains. Furthermore, rheological evaluations demonstrate high viscosity at low shear and strong shear-thinning behavior at high shear, supporting storage stability and low flow resistance during delivery. Methanol retention tests under ambient exposure and centrifugation confirm reduced solvent loss and the absence of macroscopic phase separation. Finally, combustion calorimetry indicates staged burning and higher total heat release with increasing adamantane loading, while the specific gelator chemistry controls residue formation. This approach successfully upgrades methanol into a higher-energy-density gel fuel with shear-thinning pumpability for volume-limited applications.