A method for producing a composite sulphur/carbon conductive material obtained solely from an initial sulphur and an initial carbon which includes the following successive steps between 50% and 90% by weight of initial sulphur and between 50% and 10% by weight of initial carbon having a specific surface smaller than or equal to 200 m2/g are placed in a reactor at atmospheric pressure, the sum of the proportions respectively of the initial sulphur and carbon attaining 100%, the reactor is hermetically sealed at atmospheric pressure, and the composite sulphur/carbon conductive material is formed, in powder form, by heat treatment by heating said reactor to a heating temperature comprised between 115° C. and 400° C., without external regulation of the pressure inside the reactor, and keeping said reactor at said heating temperature during a predetermined time.