This invention relates to particulate electroactive materials comprising a plurality of composite particles, wherein the composite particles comprise: (a) a porous carbon framework including micropores and optional mesopores having a total volume of at least 0.7 cm3/g and up to 2 cm3/g, wherein at least half of the total micropore and mesopore volume is in the form of pores having a diameter of no more than 1.5 nm; and (b) silicon located within the micropores and optional mesopores of the porous carbon framework in a defined amount relative to the total volume of the micropores and optional mesopores.