An electrically conducting composite is made by providing an aerogel structure of nonconducting material, exposing the aerogel structure to a mixture of RuO4 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 RuO4 decomposes into RuO2 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 RuO4 decomposes to RuO2 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 RuO4 begins to decompose into RuO2, the newly formed RuO2 is deposited throughout the aerogel structure as a three-dimensionally networked conductive deposit.