NEXEON LIMITED

The invention provides methods for providing composite particles with a carbon coating and the resulting core-shell particulate material. The process comprises subjecting a plurality of precursor composite particles to a heat treatment in contact with a pyrolytic carbon precursor such that an outer shell of a pyrolytic conductive carbon material is formed on the precursor composite particles, wherein the heat treatment is carried out at a temperature of no more than 700° C.

This invention relates to a particulate material consisting of a plurality of composite particles comprising a porous particle framework and a plurality of nanoscale elemental silicon domains located within the pores of the porous particle framework. The porous particle framework comprises micropores and mesopores, wherein the total volume of micropores and mesopores in the porous particle framework as measured by gas adsorption is from 0.5 to 1.8 cm 3 /g. The composite particles comprise from 30 to 70 wt % silicon, wherein at least 30 wt % of the silicon is surface silicon as determined by thermogravimetric analysis (TGA); no more than 1.2 wt % of hydrogen; and have a weight ratio of oxygen to silicon of no more than 0.15. The BET surface area of the composite particles is no more than 40 m 2 /g.

This invention relates to particulate electroactive materials consisting of a plurality of composite particles, wherein the composite particles comprise: (a) a porous conductive particle framework including micropores and/or mesopores having a total volume of at least 0.4 to 2.2 cm 3 /g; (b) an electroactive material disposed within the porous conductive particle framework; and (c) a lithium-ion permeable filler penetrating the pores of the porous conductive particle framework and disposed intermediate the nanoscale silicon domains and the exterior of the composite particles.

The invention relates to a process for preparing composite particles, the process comprising contacting the plurality of particles in the reaction zone with a gas comprising at least 25 vol % of a silicon-containing precursor at a temperature effective to cause deposition of silicon in the pores of the porous particles. A controlled temperature differential between the maximum temperature of the internal surfaces of the reaction zone and the simultaneous minimum temperature within the plurality of porous particles is maintained during the contacting step.

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/or mesopores having a total volume of at least 0.7 cm 3 /g, wherein at least half of the micropore/mesopore volume is in the form of pores having a diameter of no more than 5 nm; and (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.

Silicon-containing composite particles, the process comprising the steps of: (a) providing a plurality of porous particles comprising micropores and/or mesopores, wherein the D 50 particle diameter of the porous particles from 0.5 to 200 μm; the total pore volume of micropores and mesopores is from 0.4 to 2.2 cm 3 /g; and the PD 50 pore diameter is no more than 30 nm; c (b) combining a charge of the porous particles with a charge of a silicon-containing precursor in a batch pressure reactor, wherein the charge of porous particles has a volume of at least 20 cm 3 per litre of reactor volume (cm 3 /L RV ), and wherein the charge of the silicon-containing precursor comprises at least 2 g of silicon per litre of reactor volume (g/L RV ); and (c) heating the reactor to a temperature effective to cause deposition of silicon in the pores of the porous particles, thereby providing the silicon-containing composite particles.

The invention relates to a process for preparing composite particles, the process comprising contacting the plurality of particles in the reaction zone with a gas comprising at least 25 vol % of a silicon-containing precursor at a temperature effective to cause deposition of silicon in the pores of the porous particles. A controlled temperature differential between the maximum temperature of the internal surfaces of the reaction zone and the simultaneous minimum temperature within the plurality of porous particles is maintained during the contacting step.

This invention relates to particulate electroactive materials consisting of a plurality of composite particles, wherein the composite particles comprise a plurality of silicon nanoparticles dispersed within a conductive carbon matrix. The particulate material comprises 40 to 65 wt % silicon, at least 6 wt % and less than 20% oxygen, and has a weight ratio of the total amount of oxygen and nitrogen to silicon in the range of from 0.1 to 0.45 and a weight ratio of carbon to silicon in the range of from 0.1 to 1. The particulate electroactive materials are useful as an active component of an anode in a metal ion battery.

An electrochemically active material comprising a surface is provided, wherein the surface comprises an oligomer. A method of functionalising the surface with the oligomer is also provided.

This invention relates to continuous process for preparing composite particles by continuous introduction of a porous particle feedstock and a silicon precursor gas into a first reaction zone and continuous withdrawal of a composite particles and an effluent gas from the first reaction zone, the composite particles comprising a porous particle framework and elemental silicon within the pores of the porous particle framework.