Silicon or Germanium Network Structure for Use as an Anode in a Battery

Abstract

The invention provides process for producing a stable Si or Ge electrode structure comprising cycling a Si or Ge nanowire electrode until a structure of the Si nanowires form a continuous porous network of Si or Ge ligaments.

1 . A process for producing a stable Silicon, Si, or Germanium, Ge, or Tin, Sn, electrode structure comprising:
 cycling a Si or Ge or Sn nanostructure electrode until the nanostructure forms a continuous porous network of Si or Ge or Sn ligaments.   
     
     
         2 . The process of  claim 1 , wherein the process further comprises continually lithiating and delithiating the Si or Ge or Sn nanostructure electrode to form the continuous porous network of Si or Ge or Sn ligaments. 
     
     
         3 . The process of  claim 1 , wherein the electrode is cycled for at least 100 cycles. 
     
     
         4 . The process of  claim 1 , wherein the electrode is cycled at a rate of C/2. 
     
     
         5 . An anode for a lithium-ion battery comprising a continuous porous network of a lithium-alloying active material. 
     
     
         6 . The anode of  claim 5 , wherein the network comprises interwoven ligaments of the active material. 
     
     
         7 . The anode of  claim 5 , wherein the average ligament diameter comprises 5 nm. 
     
     
         8 . The anode of  claim 5 , wherein the lithium-alloying active material comprises one of Silicon, Germanium, or Tin. 
     
     
         9 . A lithium-ion battery comprising:
 the anode of  claim 5 ; and   an electrolyte comprising a solid electrolyte interphase layer former.   
     
     
         10 . The battery of  claim 5 , wherein the solid electrolyte interphase layer former comprises vinylene carbonate. 
     
     
         11 . A method for producing tin seeded Silicon or Germanium nanowires grown by solution decomposition comprising:
 evaporating tin onto the surface of stainless steel substrates;   placing the pre-treated stainless steel substrates in a chamber;   adding a high boiling point solvent to the chamber;   heating the chamber to a first temperature;   applying a vacuum to the chamber;   purging the chamber with an inert gas and increasing the temperature of the chamber to the reaction temperature; and   injecting a silicon or germanium precursor into the chamber; wherein the chemical vapour deposition of the silicon or germanium monomer from the decomposition of the injected silicon or germanium precursor produces tin seeded Silicon or Germanium nanowires via the vapour-liquid solid growth mechanism.   
     
     
         12 . The method of  claim 11 , wherein 99.99% purity tin is evaporated. 
     
     
         13 . The method of  claim 11 , further comprising the step of rinsing and drying the stainless steel substrates prior to placing the substrates in the chamber. 
     
     
         14 . The method of  claim 13 , wherein the substrates are rinsed in toluene and dried by means of a nitrogen line. 
     
     
         15 . The method of  claim 11 , wherein the vacuum is applied to the chamber for one hour. 
     
     
         16 . The method of  claim 15 , further comprising the step of providing a constant flow of inert gas to the chamber. 
     
     
         17 . The method of  claim 11 , wherein the first temperature is 125° C. 
     
     
         18 . The method of  claim 11 , wherein the high boiling point solvent comprises 7 mls of squalane. 
     
     
         19 . The method of  claim 11 , wherein the reaction temperature is 430° C. 
     
     
         20 . The method of  claim 11 , wherein the precursor is phenylsilane or diphenylgermane. 
     
     
         21 . The method of  claim 11 , further comprising the step of washing the tin seeded Silicon or Germanium nanowires. 
     
     
         22 . A Si or Ge anode for a lithium-ion battery, wherein the anode is produced using the process or method of  claim 1 .