The invention relates to a particulate material comprising a plurality of composite particles, wherein the composite particles comprise: (a) a porous carbon framework comprising micropores and mesopores having a total pore volume of at least 0.6 cm3/g and no more than 2 cm3/g, where the volume fraction of micropores is in the range from 0.5 to 0.9 and the volume fraction of pores having a pore diameter no more than 10 nm is at least 0.75, and the porous carbon framework has a D50 particle size of less than 20 μm; (b) silicon located within the micropores and/or mesopores of the porous carbon framework in a defined amount relative to the volume of the micropores and/or mesopores.