Electroactive materials for use in metal-Ion batteries

A particulate material consists of a plurality of composite particles, wherein the composite particles comprise: (a) a conductive porous particle framework including micropores and/or mesopores having a total pore volume between 0.4 - 2.2 cm3/g; (b) a plurality of electroactive material domains disposed within the conductive porous particle framework; and (c) a lithium-ion permeable filler penetrating the pores of the porous conductive particle framework and disposed intermediate the electroactive material and the exterior of the composite particles. The electroactive material may comprise Si, Sn, Ge and/or Al, and preferably comprises Si nanoscale domains. The conductive porous particles are preferably carbon but may comprise porous metal oxides (e.g. titanium oxide) instead. Preferably, the PD50 pore diameter of the porous particle framework is no more than 10 nm. The filler may be a conductive pyrolytic carbon material or a Li-ion permeable solid electrolyte. The filler may also comprise a coating over at least part of the outer surface of the composite particles. The composite particles are preferably used as an anode material in a rechargeable metal-ion battery.