Method of forming silicon
AssigneeNexeon Limited
InventorsLeigh Canham, Christopher Michael Friend, William James Macklin, Scott Brown
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Abstract
A method of forming a particulate material comprising silicon, the method comprising the step of reducing a particulate starting material comprising silica-containing particles having an aspect ratio of at least 3:1 and a smallest dimension of less than 15 microns, or reducing a particulate starting material comprising silica-containing particles comprising a plurality of elongate structural elements, each elongate structural element having an aspect ratio of at least 3:1 and a smallest dimension of less than 15 microns.
Claims61
A method of forming a particulate material comprising silicon, the method comprising the step of reducing a particulate starting material comprising silica-containing particles having an aspect ratio of at least 3:1 and a smallest dimension of less than 15 microns, or reducing a particulate starting material comprising silica-containing particles comprising a plurality of elongate structural elements, each elongate structural element having an aspect ratio of at least 3:1 and a smallest dimension of less than 15 microns.
A method according to any preceding claim wherein substantially all silica of the starting material is reduced.
A method according to any preceding claim wherein the geometric surface area of the silicon material is substantially the same as the geometric surface area of the starting material.
A method according to any preceding claim wherein the shape of the particles of the material comprising silicon is substantially the same as the shape of the starting material particles.
A method according to any preceding claim wherein the starting material is n- or p-doped.
A method according to any preceding claim wherein the starting material particles have an open framework structure.
A method according to any preceding claim wherein the starting material is reduced at a reaction temperature of no more than 750° C., optionally no more than 650° C.
A method according to any preceding claim wherein the starting material is reduced by exposure to liquid metal or metal vapour.
A method according to any preceding claim wherein the silica is reduced by exposure to a reducing composition that causes both reduction of the silica and doping of the silicon.
A method according to any preceding claim comprising the further step of coating at least part of the surface of the material comprising silicon.
A method according to any preceding claim wherein the starting material is formed by electrospinning silica.
A method according to any preceding claim wherein the starting material has a substantially enclosed void volume and the smallest dimension is a thickness of a wall of the starting material enclosing the void volume.
A method according to any preceding claim wherein the material comprising silicon has a BET value that is the same as or less than a BET value of the starting material.
A method according to any preceding claim wherein the material comprising silicon has a BET value of less than 100 m2/g.
A method according to any preceding claim wherein the starting material is no more than 95% silica by weight.
A method according to any preceding claim wherein the particulate material comprising silicon is treated to remove reaction by-products.
A method according to claim 356 wherein reaction by-products are removed by HCl treatment.
A method according to any preceding claim wherein the particulate material comprising silicon is etched to form silicon pillars extending from a silicon core of the particulate material.
A particulate material comprising silicon obtainable by a method according to any preceding claim.
An electrode according to claim4l, wherein the electrode further comprises a conductive current collector in electrical contact with the active material.
A method of forming a material comprising silicon comprising the steps of electrospinning a material comprising silica and reducing the electrospun material comprising silica.
A method of forming silicon comprising the step of reducing biogenic silica.
A method of forming a particulate material comprising silicon, the method comprising the step of reducing a particulate starting material comprising silica-containing particles wherein the particulate starting material is no more than 95% silica by weight.
A method of forming a particulate material comprising silicon, the method comprising the step of reducing a particulate starting material comprising silica-containing particles wherein the particulate material comprising silicon has a surface area per unit weight of less than 100 m2/g.
A method of forming a particulate material comprising silicon, the method comprising the step of reducing a particulate starting material comprising silica-containing particles wherein the particulate starting material is in contact with a layer of a thermal moderator.
A method of forming a particulate material comprising silicon, the method comprising the step of partially reducing silica of a particulate starting material comprising silica-containing particles, and treating the partially reduced silica to remove remaining starting material.
Dependencies are inferred from the claim text.