Structurally stable active material for battery electrodes

A process of producing active material for an electrode of an electrochemical cell containing sodium carboxymethylcellulose comprising:

• 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, an epoxy resin based on bisphenol A and epichlorohydrin, polyurethane resin and polyester resin, as component 3,
• mixing components 1 to 3 into a mixture such that component 3 comprises 20 to 80 wt % of the 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.