Submicron Sized Silicon Powder with Low Oxygen Content

Abstract

A submicron sized Si based powder having an average primary particle size between 20 nm and 200 nm, wherein the powder has a surface layer comprising SiO x , with 0<x<2, the surface layer having an average thickness between 0.5 nm and 10 nm, and wherein the powder has a total oxygen content equal or less than 3% by weight at room temperature. The method for making the powder comprises a step where a Si precursor is vaporized in a gas stream at high temperature, after which the gas stream is quenched to obtain Si particles, and the Si particles are quenched at low temperature in an oxygen containing gas.

1 - 18 . (canceled) 
     
     
         19 . A collection of particles having an average primary particle size between 20 nm and 200 nm, wherein the particles have a silicon core, wherein the particles have a covering on their surface, whereby this covering comprises SiOx with 0<x<2, the surface covering having an average thickness between 0.5 nm and 10 nm, and wherein the collection of particles has a total oxygen content equal to or less than 3% by weight. 
     
     
         20 . The collection of particles according to  claim 19 , wherein said covering is applied on the surface of the silicon core. 
     
     
         21 . The collection of particles according to  claim 19 , wherein said SiOx is SiOx with 1≦x<2. 
     
     
         22 . The collection of particles according to  claim 19 , wherein said covering consists of SiOx, with 0<x<2. 
     
     
         23 . The collection of particles according to  claim 22 , wherein said SiOx is SiOx with 1≦x<2. 
     
     
         24 . The collection of particles according to  claim 19 , wherein said covering is a layer. 
     
     
         25 . The collection of particles according to  claim 19 , wherein said surface covering has an average thickness between 0.5 nm and 5 nm. 
     
     
         26 . A powder comprising silicon particles, wherein the silicon particles have an average primary particle size between 20 nm and 200 nm, wherein the silicon particles have a surface layer, wherein the surface layer comprises SiOx with 0<x<2, the surface layer having an average thickness between 0.5 nm and 10 nm, and wherein the powder has a total oxygen content equal to or less than 3% by weight. 
     
     
         27 . The powder according to  claim 26 , wherein said SiOx is SiOx with 1≦x<2. 
     
     
         28 . The powder according to  claim 27 , wherein said surface layer consists of SiOx with 1≦x<2. 
     
     
         29 . The powder according to  claim 27 , wherein said surface layer has an average thickness between 0.5 nm and 5 nm. 
     
     
         30 . A powder comprising particles, wherein the particles have an average primary particle size between 20 nm and 200 nm, wherein the particles have a silicon core, wherein the particles comprise SiOx with 0<x<2, wherein said SiOx is present on the surface of said silicon core, wherein said SiOx has an average thickness on said silicon core of between 0.5 nm and 10 nm, and wherein the powder has a total oxygen content equal to or less than 3% by weight. 
     
     
         31 . The powder according to  claim 30 , wherein said SiOx is SiOx with 1≦x<2. 
     
     
         32 . The powder according to  claim 30 , wherein said SiOx has an average thickness on said silicon core of between 0.5 nm and 5 nm. 
     
     
         33 . A Li-ion secondary battery comprising a negative electrode, wherein the negative electrode comprises the collection of particles according to  claim 19 . 
     
     
         34 . A Li-ion secondary battery comprising a negative electrode, wherein the negative electrode comprises the powder according to  claim 26 . 
     
     
         35 . A Li-ion secondary battery comprising a negative electrode, wherein the negative electrode comprises the powder according to  claim 30 .