Lithium ion batteries with supplemental lithium

Abstract

Supplemental lithium can be used to stabilize lithium ion batteries with lithium rich metal oxides as the positive electrode active material. Dramatic improvements in the specific capacity at long cycling have been obtained. The supplemental lithium can be provided with the negative electrode, or alternatively as a sacrificial material that is subsequently driven into the negative electrode active material. The supplemental lithium can be provided to the negative electrode active material prior to assembly of the battery using electrochemical deposition. The positive electrode active materials can comprise a layered-layered structure comprising manganese as well as nickel and/or cobalt.

What is claimed is: 
     
         1 . A lithium ion battery comprising supplemental lithium, a positive electrode, a negative electrode, a separator between the positive electrode and the negative electrode and an electrolyte comprising lithium ions, the negative electrode comprising a lithium intercalation/alloying composition wherein the supplemental lithium comprises elemental lithium and wherein at least some of the supplemental lithium is initially provided as a source layer on the negative electrode. 
     
     
         2 . The lithium ion battery of  claim 1  wherein the source layer comprises a layer of lithium. 
     
     
         3 . The lithium ion battery of  claim 1  wherein the source layer comprises particulate lithium in a binder. 
     
     
         4 . The lithium ion battery of  claim 1  wherein the lithium intercalation/alloying composition comprises silicon. 
     
     
         5 . The lithium ion battery of  claim 1  wherein the lithium intercalation/alloying composition in the negative electrode is in a layer with a polymer binder. 
     
     
         6 . The lithium ion battery of  claim 5  wherein the layer with the polymer binder and lithium intercalation/alloying composition further comprises electrically conductive carbon particles. 
     
     
         7 . The lithium ion battery of  claim 1  wherein the effective capacity of the supplemental lithium from about 10% to about 55% of the initial negative electrode capacity. 
     
     
         8 . The lithium ion battery of  claim 1  wherein the positive electrode comprises LiCoO 2 . 
     
     
         9 . The lithium ion battery of  claim 1  wherein the positive electrode comprises lithium metal oxide is approximately represented by a formula Li 1+x M 1−y O 2−z F z  where M is one or more metal elements, x is from about 0.01 to about 0.33, y is from about x−0.2 to about x+0.2 with the proviso that y≥0, and z is from 0 to about 0.2. 
     
     
         10 . A method for the formation of a negative electrode for a lithium ion battery wherein the negative electrode comprises an active lithium intercalation/alloying composition, supplemental lithium and a polymer binder, the method comprising associating a source layer of supplemental lithium with the negative electrode. 
     
     
         11 . The method of  claim 10  wherein the active lithium intercalation/alloying composition is combined with a polymer binder 
     
     
         12 . The method of  claim 11  wherein conductive carbon is blended with the active lithium intercalation/alloying composition and polymer binder. 
     
     
         13 . The method of  claim 11  further comprising applying the active lithium intercalation/alloying composition combined with the polymer binder and a solvent as a film on a metal foil. 
     
     
         14 . The method of  claim 13  further comprising pressing and drying the layer on the metal foil to form a dried layer. 
     
     
         15 . The method of  claim 14  wherein the associating of the thin layer of lithium comprises application of a thin layer of lithium metal over the dried layer. 
     
     
         16 . The method of  claim 13  further comprising applying a layer of lithium particles in a polymer binder over the dried layer. 
     
     
         17 . The method of  claim 11  wherein the effective capacity of the supplemental lithium from about 10% to about 55% of the initial negative electrode capacity. 
     
     
         18 . A method for producing a lithium ion battery, the method comprising:
 immersing an electrode assembly with a non-aqueous electrolyte comprising lithium ions, wherein the electrode assembly is formed by assembling a negative electrode formed according to the method of  claim 11  with a positive electrode comprising a lithium metal oxide and a binder wherein a separator is placed between the positive electrode and a negative electrode.   
     
     
         19 . The method of  claim 18  wherein the positive electrode comprises LiCoO 2 . 
     
     
         20 . The method of  claim 18  wherein the positive electrode comprises lithium metal oxide is approximately represented by a formula Li 1+x M 1−y O 2−z F z  where M is one or more metal elements, x is from about 0.01 to about 0.33, y is from about x−0.2 to about x+0.2 with the proviso that y≥0, and z is from 0 to about 0.2. 
     
     
         21 . The method of  claim 18  wherein the source layer of lithium becomes associated with preloaded extractable lithium wherein the preloaded extractable lithium comprises above any amount of lithium consumed in association with the first cycle irreversible capacity loss of the negative electrode, from about 2 percent to about 55 percent of the total theoretical capacity of the active lithium intercallation/alloying composition less the negative electrode irreversible capacity loss. 
     
     
         22 . The method of  claim 18  further comprising cycling the battery.