Non-aqueous electrolyte secondary battery

Abstract

The present invention provides a non-aqueous electrolyte secondary battery including a positive electrode, a negative electrode having a negative active material, and a non-aqueous electrolyte, characterized in that the negative active material contains composite particle (C), which has silicon-containing particle (A) and electronic conductive additive (B), the silicon-containing particle (A) has a content of carbon, and when measured at a temperature rising rate of 10±2° C./min by thermogravimetry, said composite particle (C) exhibits two stages of weight loss in the range of 30 to 1000° C.

1 - 6 . (canceled) 
     
     
         7 . A non-aqueous electrolyte secondary battery comprising:
 a positive electrode;   a negative electrode; and   a non-aqueous electrolyte,   wherein the negative electrode contains a negative active material,   the negative active material contains a composite particle (C),   the composite particle (C) contains a silicon-containing particle (A) and an electron-conductive additive (B),   the electron-conductive additive (B) covers the surface of the silicon-containing particle (A), and   the silicon-containing particle (A) comprises equimolar amounts of Si and O.   
     
     
         8 . The non-aqueous electrolyte secondary battery according to  claim 7 , wherein the weight of the electron-conductive additive (B) falls within the range of 0.5 wt. % to 60 wt. % of the composite particle (C). 
     
     
         9 . The non-aqueous electrolyte secondary battery according to  claim 7 , the composite particles further containing carbon and the silicon-containing particle (A) and carbon are coated by the electron-conductive additive (B). 
     
     
         10 . The non-aqueous electrolyte secondary battery according to  claim 7 , wherein the electron-conductive additive (B) contains a carbon material having an average interplanar spacing d(002) of 0.3354 nm or more and less than 0.34 nm. 
     
     
         11 . The non-aqueous electrolyte secondary battery according to  claim 7 , wherein the electron-conductive additive (B) is carbon. 
     
     
         12 . The non-aqueous electrolyte secondary battery according to  claim 7 , wherein at least one of half widths of the Si (111)-plane and Si (220)-plane diffraction peaks of the silicon-containing particle (A) in X-ray diffraction measurement with CuKα radiation is less than 3° (2θ). 
     
     
         13 . The non-aqueous electrolyte secondary battery according to  claim 7 , wherein the negative active material further contains a carbon material (D). 
     
     
         14 . A method of making the non-aqueous electrolyte secondary battery of  claim 7  comprising:
 calcinating SiO at a range of temperature from 900° C. to 1400° C. and separating SiO into Si and SiO 2  to make a particle including a microcrystalline silicon phase and an amorphous SiO 2  phase. 
 
     
     
         15 . The method according to  claim 14 , wherein SiO is calcinated in N 2  or Ar. 
     
     
         16 . The method according to  claim 14  further comprising chemically depositing, concurrently with the calcinating, carbon on the surface of the particle. 
     
     
         17 . A method of making a negative active material comprising:
 calcinating SiO at a range of temperature from 900° C. to 1400° C. and separating SiO into Si and SiO 2  to make a particle including a microcrystalline silicon phase and an amorphous SiO 2  phase.   
     
     
         18 . The method of making a negative active material according to  claim 17 , wherein SiO is calcinated in N 2  or Ar. 
     
     
         19 . The method of making a negative active material according to  claim 17  further comprising chemically depositing, concurrently with the calcinating, carbon on the surface of the particle.