Layer-layer lithium rich complex metal oxides with high specific capacity and excellent cycling

Abstract

Lithium rich and manganese rich lithium metal oxides are described that provide for excellent performance in lithium-based batteries. The specific compositions can be engineered within a specified range of compositions to provide desired performance characteristics. Selected compositions can provide high values of specific capacity with a reasonably high average voltage. Compositions of particular interest can be represented by the formula, x Li 2 MnO 3 .(1−x) Li Ni u+Δ Mn u−Δ Co w A y O 2 ). The compositions undergo significant first cycle irreversible changes, but the compositions cycle stably after the first cycle.

What is claimed is: 
     
         1 . A positive electrode active material for a lithium ion battery having a room temperature specific discharge capacity from 4.6V to 2V of at least about 210 mAh/g at a discharge rate of C/10 and an irreversible capacity loss of no more than about 60 mAh/g, and comprising a layered lithium metal oxide composition approximately represented by the formula x Li 2 MnO 3 .(1−x) Li Ni u+Δ Mn u−Δ Co w A y O 2 , x is at least about 0.2 and no more than about 0.325, the absolute value of Δ is no more than about 0.3, 2u+w+y is approximately equal to 1, w is in the range from 0 to 1, u is in the range from 0.2 to 0.5 and y is no more than about 0.1, with the proviso that both (u+Δ) and w are not zero, wherein an optional fluorine dopant can replace no more than about 10 mole percent of the oxygen. 
     
     
         2 . The positive electrode active material of  claim 1  having an average voltage of at least about 3.625 when discharged from 4.6 volts to 2.0 volts at a rate of C/3. 
     
     
         3 . The positive electrode active material of  claim 1  further comprising a stabilization coating. 
     
     
         4 . The positive electrode active material of  claim 3  wherein the stabilization coating comprises fluorine. 
     
     
         5 . The positive electrode active material of  claim 3  wherein the stabilization coating comprises a metal oxide. 
     
     
         6 . The positive electrode active material of  claim 1  wherein the absolute value of Δ is no more than about 0.175, w is at least about 0.1 and no more than about 0.6 and u is at least about 0.225 and no more than about 0.45. 
     
     
         7 . The positive electrode active material of  claim 1  having an irreversible capacity loss of no more than about 50 mAh/g and a room temperature specific discharge capacity of at least about 215 mAh/g when discharged from 4.6V to 2V at a rate of C/10. 
     
     
         8 . The positive electrode active material of  claim 1  having an irreversible capacity loss of no more than about 45 mAh/g and a room temperature specific discharge capacity of at least about 220 mAh/g when discharged from 4.6V to 2V at a rate of C/10. 
     
     
         9 . A positive electrode active material for a lithium ion cell comprising a layered lithium metal oxide composition approximately represented by the formula Li 1+b Ni α Mn β Co γ A δ O 2−z F z , where b ranges from about 0.091 to about 0.14, α ranges from 0.1 to about 0.4, β range from about 0.2 to about 0.65, γ ranges from 0 to about 0.46, δ ranges from about 0 to about 0.15 and z ranges from 0 to 0.2, and where A is Mg, Sr, Ba, Cd, Zn, Al, Ga, B, Zr, Ti, Ca, Ce, Y, Nb, Cr, Fe, V, Li or combinations thereof, and having a stabilization coating, wherein when discharged at room temperature at a discharge rate of C/10 the positive electrode active material has a specific discharge capacity of at least about 215 mAh/g from 4.6V to 2V. 
     
     
         10 . The positive electrode active material of  claim 9  wherein b+α+β+γ+δ is approximately equal to 1. 
     
     
         11 . The positive electrode active material of  claim 9  wherein the stabilization coating comprises fluorine. 
     
     
         12 . The positive electrode active material of  claim 9  wherein the stabilization coating comprises a metal oxide. 
     
     
         13 . The positive electrode active material of  claim 9  wherein α ranges from 0.1125 to about 0.35 and γ ranges from 0 to about 0.35. 
     
     
         14 . The positive electrode active material of  claim 9  having an irreversible capacity loss of no more than about 50 mAh/g. 
     
     
         15 . A method for synthesizing a positive electrode active composition, the method comprising:
 co-precipitating a precursor composition comprising manganese as well as nickel and/or cobalt in selected amounts corresponding to a product composition approximately represented by the formula x Li 2 MnO 3 .(1−x) Li Ni u+Δ Mn u−Δ Co w A y O 2 , x is at least about 0.2 and no more than about 0.325, the absolute value of Δ is no more than about 0.3, 2u+w+y is approximately equal to 1, w is in the range from 0 to 1, u is in the range from 0.2 to 0.5 and y is no more than about 0.1 with the proviso that both (u+Δ) and w are not zero, wherein an optional fluorine dopant can replace no more than about 10 mole percent of the oxygen;   adding a lithium source at a selected point in the process;   heating the precursor composition to a first temperature to decompose the precursor composition to form a metal oxide; and   heating the metal oxide to a second temperature greater than the first temperature to improve the crystallinity of the metal oxide wherein the product active composition has a specific discharge capacity of at least about 210 mAh/g cycled from 4.6 volts to 2.0 volts at a rate of C/3.   
     
     
         16 . The method of  claim 15  wherein the precursors compositions are in a solution having a pH between about 6.0 and about 12.0. 
     
     
         17 . The method of  claim 15  wherein the first temperature between about 400° C. and about 800° C. 
     
     
         18 . The method of  claim 15  wherein the second temperature is at least about 650° C. 
     
     
         19 . The method of  claim 15  wherein the precursor composition comprises a carbonate. 
     
     
         20 . The method of  claim 15  wherein the lithium source is blended with the precursor composition prior to the decomposition of the precursor composition to form the metal oxide.