▎ 摘　　要

NOVELTY - A silicon-carbon composite comprises nanoscale silicon and carbon in a weight ratio of 30:70-70:30, and has a volume fraction of porosity of 20-70%. USE - The silicon-carbon composite is used as anode for lithium ion battery (claimed). ADVANTAGE - The composite has enhanced porosity and silicon-to-carbon ratio, whilst being sealable with coatings of suitable thickness. The composite is prepared by low-cost process and incorporates low-cost silicon and amounts of various allotropes of carbon that are optimized. The high level of porosity is desirable as this enables a higher level of silicon to be incorporated, and reduces swelling in the electrode. The composite provides a strong network for conduction of electrons and lithium ions. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) an anode for a lithium ion battery comprising the silicon-carbon composite; (2) a half cell for a lithium ion battery comprising the anode, a binder and a conducting additive in a weight ratio of composite to binder to conducting additive of 8:1:1; (3) a lithium ion battery comprising the anode, a cathode, an electrolyte and a separator; (4) a method for making a silicon-carbon composite comprising nanoscale silicon and carbon, comprising (a) preparing a dispersion of silicon nanoparticles by milling in water and retaining the mixture of silicon and water, and the selected forms of carbon, (b) spray drying the dispersion to form essentially spherical, micrometer-sized composite particles, (c) heat treating the composite particles to pyrolyze and/or burn off any polymers, and to strengthen the composite particles, (d) coating the composite particles with carbon to form the silicon-carbon composite, and (e) optionally, adding additional elements such as lithium, magnesium, nitrogen and halogen gases to the composite, either during the heating step (c) or coating step (d) or during a subsequent heat treatment step, or (i) preparing a dispersion of silicon nanoparticles by milling in water and retaining the mixture of silicon and water, (ii) optionally, preparing a separate dispersion of selected forms of carbon in water, optionally comprising one or more surfactants, (iii) adding the carbon dispersion and optional surfactant mixture (or carbon in non-dispersed form) to the silicon-water dispersion, (iv) dispersing the resultant mixture, (v) spray drying the resultant dispersed silicon-carbon mixture to form essentially spherical particles, (vi) heat treating the essentially spherical particles to pyrolyze and/or burn off any polymers, and to strengthen the spherical silicon-carbon particles, (vii) coating the heat treated spherical silicon-carbon particles with carbon using a chemical vapor deposition process to form a carbon-coated silicon-carbon composite and (viii) optionally, adding additional elements such as lithium, magnesium, nitrogen and halogen gases to the carbon-coated silicon-carbon composite, during step (c) or step (d) or during subsequent heat treatment; (5) a carbon-coated silicon-carbon composite comprising nanoscale silicon and carbon, made by the above process; and (6) silicon-carbon composite particles comprising at least 40% silicon with respect to carbon, and at least 50% pores, where the carbon is comprised of graphene and carbon nanotubes, the amount of graphene with respect to the total amount of graphene and carbon nanotubes is at least 40%.