Abstract: The present invention relates to a heat accumulator composite material, a method for the manufacture thereof and a heat accumulator device. The object of the invention is therefore to provide heat accumulator materials, a method for the manufacture thereof and heat accumulator devices that exhibit high thermal capacities and heat accumulator capacities. The solution of the object is accomplished through a heat accumulator composite material that comprises a plurality of carbon particles and a thermally conducting material, wherein the material differs from the carbon particles. The manufacture of the thermal accumulator composite material according to the invention is accomplished by combining a plurality of carbon particles and a thermally conducting material for the formation of a mixture, and heating the mixture in a partial vacuum to a temperature above the melting point of the thermally conducting material.