Method for producing silicon-based anodes for secondary batteries

Abstract

A method for producing silicon-based anodes for secondary batteries carries out the following steps for producing an anode: —depositing a silicon layer on a metal substrate having grain boundaries, wherein the silicon layer has a first boundary surface directed towards the metal substrate, —heating the metal substrate using a heating unit to a temperature between 200° C. and 1000° C., —conditioning the region of the second boundary surface of the silicon layer that is facing away from the metal substrate using an energy-intensive irradiation during the heating, generating polyphases in the region of the silicon layer and the metal substrate, made up of amorphous silicon and/or crystalline silicon of the silicon of the silicon layer and of crystalline metal of the metal substrate and of silicide and—generating crystalline metal of the metal substrate.

What is claimed is: 
     
         1 . A silicon-based anode ( 20 ) for secondary batteries ( 30 ),
 wherein the secondary batteries ( 30 ) comprise at least the anode, at least one electrolyte ( 31   a ,  31   b ) and a counter-electrode ( 33 );   wherein the anode ( 20 ) is manufactured according to a method comprising the following steps:   depositing a silicon layer ( 3 ) on a metal substrate ( 1 ), wherein the silicon layer ( 3 ) has a first interface ( 14 ) directed toward the metal substrate ( 1 );   heating the metal substrate ( 1 ) by means of a heating unit ( 22 ) to a temperature between 200° C. and 1000° C., wherein the heating unit ( 22 ) is associated with the metal substrate ( 1 ) and is directed toward the metal substrate ( 1 );   tempering the region of a second interface ( 15 ) of the silicon layer ( 3 ) turned away from the metal substrate ( 1 ) by means of an energy-intensive irradiation during the heating;   generating multiple phases ( 10 ,  11 ) in the region of the silicon layer ( 3 ) and of the metal substrate ( 1 ), comprising amorphous silicon of the silicon layer ( 3 ) and crystalline metal of the metal substrate ( 1 ); and   generating crystalline metal ( 8 ) of the metal substrate ( 1 );   wherein the irradiation and the tempering are performed with an energy source comprising gas discharge lamps, which emit radiation in the wavelength region between 400 nm-800 nm and a flash duration between 0.2 ms and 20 ms to a temperature of up to 2000° C.;   wherein the anode ( 20 ) at least comprises:   the metal substrate ( 1 ), functioning as carrier material and as current lead;   the silicon layer ( 3 ) deposited on the metal substrate ( 1 ), with a formation of the first interface ( 14 ) to the metal substrate ( 1 ); and   multiple phases ( 10 ,  11 ) of amorphous silicon, silicon and crystalline metal in the region of the metal substrate ( 1 ) and of the silicon layer ( 3 ) and multiple phases of silicide, wherein a metal-induced crystallization between the material of the metal substrate ( 1 ) and the material of the silicon layer ( 3 ) is realized   
     
     
         2 . The anode according to  claim 1 , wherein at least one buffer layer ( 4   b ) is situated in the region of the first interface ( 14 ) between metal substrate ( 1 ) and the silicon layer ( 3 ). 
     
     
         3 . The anode according to  claim 1 , wherein at least one buffer layer ( 4   a ) is applied on a second interface ( 15 ) of the silicon layer ( 3 ) turned away from the metal substrate ( 1 ). 
     
     
         4 . An arrangement ( 21 ) comprising:
 the anode ( 20 ) according to  claim 1 ;   at least one energy-intensive energy source ( 6 ), which is directed with its energy flow toward the silicon layer ( 3 ) of the anode ( 20 );   a heating unit ( 22 ), which is associated with the metal substrate ( 1 ) and is directed toward the metal substrate ( 1 ) and at least heats the metal substrate ( 1 ) and the silicon layer ( 3 ) to a temperature between 200° C. and 1000° C.;   wherein, during the heating, the energy source ( 6 ) is directed toward the second interface ( 15 ) of the silicon layer ( 3 ) turned away from the metal substrate ( 1 ) for the transmission of short-time high energy ( 7 ).   
     
     
         5 . The arrangement according to  claim 4 , wherein the energy-intensive energy source ( 6 ) at least comprises:
 at least one flash lamp ( 6 ), which is directed toward the second interface ( 15 ) of the silicon layer ( 3 ) of the anode ( 20 );   at least one reflector ( 5 ) associated with the flash lamp ( 6 );   wherein, during the heating, the flash-lamp light ( 7 ) is directed toward the second interface ( 15 ) of the silicon layer ( 3 ) turned away from the metal substrate ( 1 ) for the transmission of short-time high energy.   
     
     
         6 . A secondary battery ( 30 ) with the anode ( 20 ) according to  claim 1 , comprising at least the components:
 a cathode ( 33 );   a first electrolyte ( 31   a );   a separator ( 32 );   a second electrolyte ( 31   b );   wherein the anode ( 20 ) is arranged after the second electrolyte ( 31   b );   wherein the components: cathode ( 33 ), first electrolyte ( 31   a ), separator ( 32 ), second electrolyte ( 31   b ) and anode ( 20 ) are combined in layered manner in the said order within the secondary battery ( 30 ).