Presented here is the formulation and characterization of a stable aluminum slurry fuel that reacts readily and exothermically with liquid water to produce hydrogen gas and AlOOH (boehmite). Bulk pure aluminum is first surface-treated with a gallium-indium 2 April 2020 eutectic, then ground into a powder and suspended in mineral oil containing 4-8 wt% fumed silica as a shear-thinning agent. Aluminum mass fractions of up to 65 wt% are shown here. This formulation results in a slurry fuel that can be pumped continuously at low power while remaining in suspension for over 2 months. The fuel is also shown here to exhibit a high degree of reaction completion (93.4%) with a total measured energy density of 28.7 MJ/L and specific energy of 17.5 MJ/kg. Finally, to show the feasibility of using this fuel for on-demand hydrogen production in a representative power system, a prototype continuous-flow reactor was developed, and validation experiments were performed, the results of which are presented here. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.