A process of producing active material for an electrode of an electrochemical cell includes providing lithium-intercalating carbon particles having an average particle size of 1 μm to 100 μm as component 1, providing silicon particles having an average particle size of 5 nm to 500 nm as component 2, providing a polymer or polymer precursor which can be pyrolyzed to form amorphous carbon and is selected from the group consisting of epoxy resin, polyurethane resin and polyester resin, as component 3, mixing components 1 to 3 in to a mixture and heat treating the mixture substantially in the absence of atmospheric oxygen at a temperature at which the pyrolyzable polymer or the pyrolyzable polymer precursor decomposes to form amorphous carbon.