Positive electrodes for lithium batteries

Abstract

Lithium-rich compounds that are precursors for positive electrodes for lithium cells and batteries comprise a Li 2 O-containing compound as one component, and a second charged or partially-charged component, selected preferably from a metal oxide, a lithium-metal-oxide, a metal phosphate or metal sulfate compound. Li 2 O is extracted from the electrode precursors to activate the electrode either by electrochemical methods or by chemical methods. Methods for synthesizing and activating the electrodes, electrochemical cells, and batteries containing such electrodes also are described.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 
     
         1 . A non-aqueous lithium electrochemical cell comprising a negative electrode and an activated positive electrode with a lithium-containing non-aqueous electrolyte therebetween; wherein the activated positive electrode is prepared by;
 combining a first component and a second component to form a precursor material, wherein the first component contains one or more metal cation and Li 2 O-containing materials; and the second component contains one or more charged or partially-charged metal cation-containing electrode materials selected from the group consisting of a charged or partially charged lithium metal oxide, a charged or partially charged metal phosphate, and a charged or partially charged metal sulfate, which can accommodate lithium within their structure during the charging and discharging of the electrode when included in an electrochemical cell, with the proviso that at least one of the first and second components does not contain manganese;   fabricating an electrode from the precursor material; and   subsequently electrochemically activating the positive electrode by applying a sufficiently high potential to the electrode in the electrochemical cell to remove Li 2 O from the precursor material, such that lithium is electrochemically extracted from the positive electrode to load the anode therewith;   wherein the negative electrode comprises one or more material selected from carbon, a metal, a semimetal, an intermetallic material, and a metal oxide.   
     
     
         2 . The electrochemical cell of  claim 1 , wherein the first component comprises an intergrown or blended composite structure comprising two or more Li 2 O-containing components of different molecular structure. 
     
     
         3 . The electrochemical cell of  claim 1 , wherein the metal cations of the first component comprise one or more of Mn, V, Fe and Ti cations. 
     
     
         4 . The electrochemical cell of  claim 3 , wherein the first component comprises one or more materials selected from the group consisting of Li 2 O.MnO 2 , Li 2 O.3V 2 O 5 , 3Li 2 O.V 2 O 5 , Li 2 O.2.5Fe 2 O 3 , Li 2 O.Fe 2 O 3 , 5Li 2 .Fe 2 O 3 , and Li 2 O.TiO 2 . 
     
     
         5 . The electrochemical cell of  claim 3 , wherein the first component comprises one or more materials selected from the group consisting of a Li 2 MnO 3  and LiMO 2 -containing material and a Li 2 MnO 3  and LiM′ 2 O 4 -containing material; wherein M and M′ are independently one or more metal cations. 
     
     
         6 . The electrochemical cell of  claim 5 , wherein M comprises one or more of Mn, Ni, and Co; and wherein M′ comprises Li and Mn. 
     
     
         7 . The electrochemical cell of  claim 1 , wherein the negative electrode comprises one or more material selected from graphite, Sn, Si, Cu 6 Sn 5  and Li 4 Ti 5 O 12 . 
     
     
         8 . The electrochemical cell of  claim 1 , wherein the second component comprises one or more of Li 1+x V 3 O 8  in which 0≦x≦0.3, Li 1−y FePO 4  in which 0<y≦1, and Fe 2 (SO 4 ) 3 . 
     
     
         9 . The electrochemical cell of  claim 1 , wherein first component comprises one or more materials selected from the group consisting of Li 2 .MnO 2 , Li 2 O.3V 2 O 5 , 3Li 2 .V 2 O 5 , Li 2 O.2.5Fe 2 O 3 , Li 2 O.Fe 2 O 3 , 5Li 2 .Fe 2 O 3 , and Li 2 O.TiO 2 ; and the second component comprises one or more of Li 1+x V 3 O 8  in which 0≦x≦0.3, Li 1−y FePO 4  in which 0<y≦1, and Fe 2 (SO 4 ) 3 . 
     
     
         10 . The electrochemical cell of  claim 1 , wherein the Li 2 O-containing material of the first component comprises one or more of Mn, Fe, V and Co cations. 
     
     
         11 . The electrochemical cell of  claim 1 , wherein the positive electrode is either crystalline, partially crystalline, or amorphous. 
     
     
         12 . An activated positive electrode for a non-aqueous lithium cell prepared by combining:
 (a) a first component containing one or more metal cation- and Li 2 O-containing materials; and   (b) a second component containing one or more charged or partially-charged metal cation-containing electrode materials selected from the group consisting of a charged or partially charged lithium metal oxide, a charged or partially charged metal phosphate, and a charged or partially charged metal sulfate, which can accommodate lithium within their structure during the charging and discharging of the electrode when included in an electrochemical cell, to form a precursor material; fabricating an electrode from the precursor material, and subsequently electrochemically activating the electrode by applying a sufficiently high potential to the electrode in an electrochemical cell also including a negative electrode and a non-aqueous electrolyte to remove Li 2 O from the precursor material;   wherein the first component comprises an intergrown composite structure or a blend of compounds containing the Li 2 O-containing material;   with the proviso that at least one of the first and second components does not contain manganese.   
     
     
         13 . The electrode of  claim 12 , wherein the Li 2 O-containing material comprises a lithium manganese-oxide or lithium-iron oxide component. 
     
     
         14 . The electrode of  claim 13 , wherein the Li 2 O-containing material comprises Li 2 MnO 3  or Li 5 FeO 4 . 
     
     
         15 . The electrode of  claim 12 , wherein the first component further comprises a lithium metal oxide component, LiMO 2 , in which M comprises a transition metal cation. 
     
     
         16 . The electrode of  claim 15 , wherein M comprises one or more of Mn, Ni and Co. 
     
     
         17 . The electrode of  claim 15 , wherein the transition metal is combined with one or more other metal ions. 
     
     
         18 . The electrode of  claim 15 , wherein the transition metal is combined with one or more of Al and Mg. 
     
     
         19 . The electrode of  claim 15 , wherein the second component comprises a charged or partially-charged metal oxide, a lithium metal oxide, a metal phosphate, or a metal sulfate. 
     
     
         20 . The electrode of  claim 19 , wherein the second component is a charged or partially-charged lithium metal oxide. 
     
     
         21 . The electrode of  claim 20 , wherein the metal of the charged or partially-charged lithium metal oxide comprises one or more transition metal. 
     
     
         22 . The electrode of  claim 21 , wherein the transition metal is selected from Mn, V and Fe. 
     
     
         22 . A non-aqueous lithium battery comprising a plurality of electrically connected electrochemical cells of  claim 1 . 
     
     
         23 . An electrochemical cell comprising the positive electrode of  claim 12 , a negative electrode spaced from the positive electrode, and a lithium-containing non-aqueous electrolyte in contact with the positive and negative electrodes. 
     
     
         24 . A non-aqueous lithium battery comprising a plurality of electrically connected electrochemical cells of  claim 23 .