Lithiated silicon/carbon composite materials and method for producing the same

Abstract

The invention relates to composite materials comprising lithiated or partially-lithiated graphite or graphene, and silicon having particles sizes from about 1 μm to about 100 μm, and that have an electrochemical rest potential less than about 2 V measured against Li/Li + , wherein graphitic material is mixed with silicon powder in a molar ratio of 9:1 to 1:9 and with lithium powder to an amount of the lithium in the composite material in the range of about 10 molar % to 100 molar % of the stochiometrically maximally possible lithium absorption, and to methods for production thereof.

We claim: 
     
         1 . Composite materials comprising lithiated or partially-lithiated graphite or graphene and silicon having particle sizes from about 1 μm to about 100 μm, and having an electrochemical rest potential less than about 2 V measured against Li/Li + . 
     
     
         2 . The composite materials of  claim 1  that additionally comprise metallic lithium. 
     
     
         3 . The composite materials of  claim 1  having a coating layer comprising functional groups or molecular constituents that have reacted with lithium that was available on the composite materials' surfaces. 
     
     
         4 . The composite materials of  claim 3  wherein the coating layer is applied with one or more gaseous or liquid coating means. 
     
     
         5 . A method for producing composite materials comprising combining (i) a graphitic material with particle sizes from about 5 μm to about 200 μm and a silicon powder with particle sizes from about 1 μm to about 100 μm in a molar ratio of 9:1 to 1:9 with (ii) a lithium powder with a particle sizes from about 5 μm to about 500 μm under inert gas conditions to form a combination and mechanochemically converting the combination in a temperature range of about 0° C. to about 120° C. under inert gas or in a vacuum, into the composite materials, wherein the amount of lithium in the composite materials is in the range of about 10 molar % to about 100 molar % of the stochiometrically maximally possible lithium absorption. 
     
     
         6 . The method of  claim 5 , wherein the mechanochemically converting is conducted in a temperature range of about 20° C. to about 100° C. 
     
     
         7 . The method of  claim 5  comprising also combining metallic lithium particles having sizes between about 5 μm to about 500 μm to form the combination. 
     
     
         8 . The method of  claim 7  further comprising subjecting the produced composite materials to a temperature of about 150° C. to about 350° C. for about 5 minutes to about 24 hours. 
     
     
         9 . The method of  claim 5  additionally comprising applying to the produced composite materials a coating layer comprising functional groups or molecular constituents such that the functional groups or molecular constituents react with lithium available on the composite materials' surfaces. 
     
     
         10 . The method of  claim 9  comprising applying the coating layer via a gaseous coating agent or a liquid coating agent. 
     
     
         11 . The method of  claim 10 , wherein the gaseous coating agent is selected from N 2 , CO 2 , CO, O 2 , N 2 O, NO, NO 2 , HF, F 2 , PF 3 , PF 5 , and POF 3 , and the liquid coating agent is selected from carbonic acid esters, vinyl ethylene carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate; lithium chelateoborate solutions in organic solvents, and inorganic compounds. 
     
     
         12 . Use of composite materials that comprise lithiated or partially-lithiated graphite or graphene and silicon particles having sizes from about 1 μm to about 100 μm, and that have an electrochemical rest potential less than about 2 V measured against Li/Li + , as anode material in galvanic cells with non-aqueous electrolytes. 
     
     
         13 . Use of composite materials that comprise lithiated or partially-lithiated graphite or graphene and silicon particles having sizes from about 1 μm to about 100 μm, and that have an electrochemical rest potential less than about 2 V measured against Li/Li + , as anode material in lithium batteries.