An electrically conducting composite is made by providing an aerogel structure of nonconducting material, exposing the aerogel structure to a mixture of RuO.sub.4 and a nonpolar solvent in an inert atmosphere, wherein the mixture is held initially at a first temperature that is below the temperature at which RuO.sub.4 decomposes into RuO.sub.2 in the nonpolar solvent and in the presence of the aerogel, and allowing the mixture to warm to a second temperature that is above the temperature at which RuO.sub.4 decomposes to RuO.sub.2 in the nonpolar solvent and in the presence of the aerogel, wherein the rate of warming is controlled so that as the mixture warms and the RuO.sub.4 begins to decompose into RuO.sub.2, the newly formed RuO.sub.2 is deposited throughout the aerogel structure as a three-dimensionally networked conductive deposit.