TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The additive is selected from carbon, zeolite, graphite, silicon, silicon oxides, tin oxides, titanium oxides, vanadium oxides, metals, metal alloys, metal oxides, metal nitrides, metal carbides, metallic compounds, silicon-containing polymers, boron containing polymers, and phosphorus containing polymers, and/or inorganic and organic compounds. The metallic compound comprises metals selected from titanium, zirconium, vanadium, niobium, chromium, molybdenum, manganese, iron, ruthenium, cobalt, nickel, palladium, copper, silver, zinc, lead, hafnium, tungsten, barium, aluminum, platinum, silicon, phosphorus, arsenic, lithium, gallium, tin, antimony, bismuth, vanadium, magnesium, calcium, strontium, boron, indium, silicon, germanium, scandium and/or yttrium.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: The additive is mixed with the polyimide precursor powder after imidization and solvent removal to produce the mixture, where the additive is added in the solution of poly(amic acids) before imidization and solvent removal to produce the mixture. The porous carbon foam composite is an activated carbon/carbon (AC/C) composite, and the additive comprises activated carbon powder, and/or carbon fiber. The mixture is compressed under pressure of 2000-13000 psi. The pyrolysis is conducted at 600-3500 (preferably below 1000) degrees C and having a carbon phase with surface area at or 300 m2/gram. The consolidation of the mixture is performed by contacting the mixture with a substrate with at least one surface of the consolidated mixture binding to the substrate. The substrate comprises solid plate, woven metal mesh, bed of solid particles, woven fiber pad and non-woven fiber pad. The porous carbon foam composite is monolithic, granular, or irregularly shaped. The metallic compound is added during the preparation of the polyimide precursor powder or added to the mixture. EXAMPLE - p-Phenylene diamine (1.622 g) was dissolved in dimethylacetamide (40 ml) in a flask. While stirring, pyromellitic dianhydride (3.270 g) was added to the reaction system. The reaction was carried out at ambient temperature with stirring until a viscous solution was formed. The reaction temperature was raised to 150 degrees C with strong agitation to produce polyimide precipitate. The solvent was distilled off under vacuum at 50 degrees C. The powders were further annealed at 300 degrees C for 30 minutes to form polyimide powder. Polyimide powder (9 g), activated carbon powder (6.1 g), and carbon fiber (0.84 g) were mixed and blended into a homogeneous mixture. The mixture was compressed at 5500 psi at ambient temperature. The plate was pyrolyzed at 800 degrees C under protection of nitrogen for 3 hours to produce AC/C composite having a density of 0.5 g/cc and a thickness of 7 mm.