Lithium cell and method of forming same

Abstract

An electrochemical cell including an anode comprising a carbonaceous material, where the carbonaceous material is capable of reversibly incorporating lithium ions therein and lithium metal on the surface thereof, a cathode capable of reversibly incorporating therein lithium ions, and a non-aqueous electrolyte in contact with the anode and the cathode, where the ratio of the capacity to reversibly incorporate lithium ions of the cathode to the capacity to reversibly incorporate lithium ions in the form of LiC 6 of the carbonaceous material of the anode is equal to or larger than 4.5:1.

What is claimed is: 
     
         1 . An electrochemical cell comprising:
 an anode comprising a carbonaceous material, said carbonaceous material is capable of reversibly incorporating lithium ions therein and lithium metal on the surface thereof;   a cathode capable of reversibly incorporating therein lithium ions; and   a non-aqueous electrolyte in contact with said anode and said cathode;   wherein the ratio of the capacity to reversibly incorporate lithium ions of said cathode to the capacity to reversibly incorporate lithium ions in the form of LiC 6  of said carbonaceous material of said anode is equal to or larger than 4.5:1.   
     
     
         2 . The cell according to  claim 1  wherein said anode comprises an electrically conducting support member, said carbonaceous material is attached to said support member. 
     
     
         3 . The cell according to  claim 2  wherein said electrically conducting support member comprises a material selected from the group consisting of an electrically conducting polymer, an electrically conducting material, a metal, copper, nickel, stainless steel, chromium, gold and combinations thereof. 
     
     
         4 . The cell according to  claim 1  wherein said cell is selected from a primary electrochemical cell and a rechargeable electrochemical cell. 
     
     
         5 . The cell according to  claim 1  wherein said carbonaceous material comprises a substance selected from graphite, coke, petroleum coke, carbon, partially or fully graphitized carbon forms, carbon-black, hard carbon and combinations thereof. 
     
     
         6 . The cell according to  claim 1  wherein said carbonaceous material comprises a layer having a thickness equal to or smaller than 2 microns. 
     
     
         7 . The cell according to  claim 1  wherein said electrolyte comprises one or more non-aqueous solvents and at least one lithium salt dissolved in said one or more non-aqueous solvents. 
     
     
         8 . The cell according to  claim 7  wherein said cell further includes a separator for separating said cathode from said anode and wherein said electrolyte impregnates said separator. 
     
     
         9 . The cell according to  claim 1  wherein the said electrolyte comprises a solid ion-conducting polymer in contact with said anode and said cathode. 
     
     
         10 . The cell according to  claim 1  wherein said cell in the charged state comprises a layer of metallic lithium deposited on said carbonaceous material. 
     
     
         11 . The cell according to  claim 1  wherein said cathode comprises a lithiated transition metal intercalation active material. 
     
     
         12 . The cell according to  claim 11  wherein said lithiated transition metal intercalation active material comprises one or more compounds selected from a lithiated transition metal oxide, a lithiated transition metal salt, a mixed lithiated transition metal oxide, a mixed lithiated transition metal salt, a lithiated metal phosphate, lithiated cobalt oxides, LiCoO 2 , LiNiCoO 2 , LiAlNiCoO 2 , LiMnNiCoO 2 , LiMnO 2 , Li 2 Mn 2 O 4 , LiV 2 O 5 , and LiFe(PO 4 ). 
     
     
         13 . The cell according to  claim 11  wherein said cathode comprises an electrically conducting support member, said lithiated transition metal intercalation active material is attached to said support member. 
     
     
         14 . An electrochemical cell comprising:
 an anode comprising an electrically conducting support member and a carbonaceous material attached to said support member, said carbonaceous material is capable of reversibly incorporating lithium ions therein and lithium metal on the surface thereof;   a cathode capable of reversibly incorporating therein lithium ions; and   a non-aqueous electrolyte in contact with said anode and said cathode;   wherein prior to charging said cell, said cathode is lithiated by an amount of lithium ions that is equal to or larger than 4.5 times the capacity of said carbonaceous material of said anode to intercalate therein lithium ions in the form of LiC 6 .   
     
     
         15 . A method for constructing an electrochemical cell, the method comprising the steps of:
 providing an anode comprising a carbonaceous material attached to a support member, said carbonaceous material is capable of reversibly incorporating lithium ions therein and lithium metal on the surface thereof;   providing a cathode capable of reversibly intercalating therein lithium ions wherein in the cell's discharged state said cathode is lithiated by an amount of lithium ions that is equal to or larger than 4.5 times the capacity of said carbonaceous material of said anode to intercalate therein lithium ions in the form of LiC 6 ;   providing a non-aqueous electrolyte;   assembling said cathode, said anode and said electrolyte in a housing to obtain said electrochemical cell.   
     
     
         16 . The method according to  claim 15  further including the step of sealing said housing. 
     
     
         17 . The method according to  claim 15  further including the step of charging said electrochemical cell after said step of assembling. 
     
     
         18 . The method according to  claim 15  further including the step of charging said electrochemical cell to deposit lithium metal on said carbonaceous material. 
     
     
         19 . The method according to  claim 18  wherein said depositing of lithium metal on said carbonaceous material increases the internal pressure within the cell to reduce lithium dendrite formation. 
     
     
         20 . The method according to  claim 15  wherein said support member is an electrically conducting support member.