Electrode surface engineering in lithium ion batteries

Abstract

A method to form a coated cathode material may generally include forming, via chemical vapor deposition, an interfacial layer coating on an exterior surface of a cathode active material, wherein the interfacial layer comprises an organic polymer; and wherein the interfacial layer is substantially uniform on and conformal to the exterior surface of the cathode active material. The polymer may include poly(3,4-ethylenedioxythiophene) (PEDOT). Methods of making and using the same are also described.

What is claimed is: 
     
         1 . A coated cathode material comprising:
 a substrate comprising a cathode active material; and   an interfacial coating in contact with at least a portion of an exterior surface of the substrate,   wherein the cathode active material comprises a lithium transition metal oxide,   wherein the cathode active material comprises a particle having a diameter from 10 nm to 100 μm,   wherein the interfacial coating comprises one of a polythiophene, a polypyrrole, a polyselenophene, a polyaniline, and derivatives and combinations thereof, and   wherein the interfacial coating has a thickness of 10-100 nm.   
     
     
         2 . The material of  claim 1 , wherein the interfacial coating comprises one of poly(3,4 ethylenedioxythiophene), poly(1,3-dihydroisothianapthene), poly (2-thiophene acetic acid), poly(3-thiopheneethanol), and derivatives and combinations thereof. 
     
     
         3 . The material of  claim 1 , wherein the interfacial coating comprises poly(3,4 ethylenedioxythiophene). 
     
     
         4 . The material of  claim 1 , wherein the interfacial coating comprises one of a polyene, a poly(siloxane), a poly(silazane), a polyfuran, and combinations thereof. 
     
     
         5 . The material of  claim 1 , wherein the interfacial coating comprises one of polydimethylsiloxane, polyhexavinyldisiloxane, poly(ethylene oxide), poly(isobenzofuran), polyoxymethylene, poly(1,3,5-trimethyl-1,3,5-trivinyl cyclotrisiloxane), poly(1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane), poly(1,3,5-trivinyl-1,3,5-trimethyl-cyclotrisilazane), poly(1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasilazane), and combinations thereof. 
     
     
         6 . The material of  claim 1 , wherein the cathode active material comprises one of lithium nickel manganese cobalt oxide, lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide, and combinations thereof. 
     
     
         7 . The material of  claim 1 , wherein the cathode active material comprises lithium manganese oxide (LiMn 2 O 4 ). 
     
     
         8 . The material of  claim 1  comprising:
 a cycling life of at least 40% greater than a cycling life of a cathode material lacking the interfacial layer coating. 
 
     
     
         9 . The material of  claim 1  comprising:
 a specific capacity tested at 5 C at least 50% greater than a specific capacity of a cathode material lacking the interfacial layer coating. 
 
     
     
         10 . The material of  claim 1  comprising:
 a low temperature (0° C.) capacity greater than 10 mAh/g at 5 C; 
 a room temperature (25° C.) capacity greater than 40 mAh/g at 10 C; and 
 a high temperature (50° C.) capacity greater than 80 mAh/g at 10 C. 
 
     
     
         11 . The material of  claim 1 , wherein the interfacial coating comprises as least one coordination site for a free acid formed by one of hydrolysis and decomposition of an electrolyte for a lithium ion battery. 
     
     
         12 . The material of  claim 1  comprising at least one oxide bond and sulfide bond between the cathode active material and the interfacial coating sufficient to stabilize and inhibit disproportionation of the cathode active material. 
     
     
         13 . A rechargeable battery comprising:
 an anode;   a cathode comprising the coated cathode material of  claim 1 ; and   optionally, an electrolyte.   
     
     
         14 . The material of  claim 1  obtainable by oxidative chemical vapor deposition. 
     
     
         15 . A coated cathode material obtainable by oxidative chemical vapor deposition, the coated cathode material comprising:
 a substrate comprising a lithium transition metal oxide cathode active material; and   a polymerized thiophene interfacial coating in contact with at least a portion of an exterior surface of the substrate,   wherein the cathode active material comprises a particle having a diameter from 10 nm to 100 μm, and   wherein the interfacial coating has a thickness of 10-100 nm.   
     
     
         16 . The material of  claim 14 , wherein the cathode active material comprises lithium manganese oxide (LiMn 2 O 4 ), and wherein the interfacial coating comprises poly(3,4 ethylenedioxythiophene). 
     
     
         17 . The material of  claim 14  comprising:
 a cycling life of at least 40% greater than a cycling life of a cathode material lacking the interfacial layer coating; and 
 a specific capacity tested at 5 C at least 50% greater than a specific capacity of a cathode material lacking the interfacial layer coating. 
 
     
     
         18 . The material of  claim 14  comprising:
 a low temperature (0° C.) capacity greater than 10 mAh/g at 5 C; 
 a room temperature (25° C.) capacity greater than 40 mAh/g at 10 C; and 
 a high temperature (50° C.) capacity greater than 80 mAh/g at 10 C. 
 
     
     
         19 . The material of  claim 14 , wherein the interfacial coating comprises as least one coordination site for a free acid formed by one of hydrolysis and decomposition of an electrolyte for a rechargeable battery. 
     
     
         20 . The material of  claim 14  comprising at least one oxide bond and sulfide bond between the cathode active material and the interfacial coating sufficient to stabilize and inhibit disproportionation of the cathode active material.