Electroactive materials for metal-ion batteries

A particulate material comprising a plurality of composite particles, wherein the composite particles comprise:

• (a) a porous carbon framework comprising micropores and/or mesopores, wherein
• the micropores and mesopores have a total pore volume as measured by gas adsorption of P1 cm3/g, wherein P1 has a value of 0.69 to 1.21, and
• the micropore fraction of the porous carbon framework as measured by gas adsorption is from 0.54 to 0.78;
• and
• (b) silicon located within the micropores and/or mesopores of the porous carbon framework,
• wherein
• the composite particles have a D90 particle diameter of no more than 10 μm;
• the silicon content of the composite particles is from 45 wt % to 59 wt %;
• the particulate material has a Z value of no more than 10% as determined by TGA analysis in air, in which Z=1.875×[(Mf−M800)/Mf]×100%, in which Mf is the mass of the TGA sample at completion of oxidation and M800 is the mass of the TGA sample at 800° C., and wherein the Z value is the percentage of unoxidized silicon at 800° C.;
• and
• the composite particles have a BET surface area of no more than 30 m2/g.