Activated carbon materials and methods of producing and using activated carbon materials are provided. In particular, biomass-derived activated carbon materials and processes of producing the activated carbon materials with prespecified surface areas and pore size distributions are provided. Activated carbon materials with preselected high specific surface areas, porosities, sub-nm (<1 nm) pore volumes, and supra-nm (1-5 nm) pore volumes may be achieved by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process.
 The present invention was made, at least in part, with government support under Award ID 0438469 from the National Science Foundation, under Award DE-FG36-08GO18142 from the Department of Energy, and under Award ID 500-08-022 from the California Energy Commission. Accordingly, the United States Government and the State of California have certain rights in this invention.