Solid-state multi-layer electrolyte, electrochemical cell and battery including the electrolyte, and method of forming same

Abstract

An electrochemical cell including a multi-layer solid-state electrolyte, a battery including the cell, and a method of forming the battery and cell are disclosed. The electrolyte includes a first layer that is compatible with the anode of the cell and a second layer that is compatible with the cathode of the cell. The cell exhibits improved performance compared to cells including a single-layer electrolyte.

1 . A solid-state electrochemical cell based on lithium ion transport, the cell comprising:
 an anode;   a composite cathode comprising electroactive cathode material; and   a solid-state electrolyte interposed between the anode and cathode, wherein the solid-state electrolyte comprises:
 a first electrolyte layer that is stable with regard to the anode; and 
 a second electrolyte layer that is stable with regard to the cathode. 
   
     
     
         2 . The solid-state electrochemical cell of  claim 1 , wherein the anode material comprises a material selected from the group consisting of lithium metal, indium metal, nano-silicon composite material, silicon alloys, carbon, and combination of these materials. 
     
     
         3 . The solid-state electrochemical cell of  claim 1 , wherein the cathode comprises an oxide material, an electrically-conducting carbon material, and second electrolyte layer material. 
     
     
         4 . The solid-state electrochemical cell of  claim 1 , wherein the electroactive cathode material is selected from the group consisting of LiCoO 2 , Li 1 N 0.85 Co 0.1 Al 0.05 O 2 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiFePO 4 , LiMn 2 O 4 , and a combination of these materials. 
     
     
         5 . The solid-state electrochemical cell of  claim 1 , wherein the cathode active material has an average particle size ranging from about 0.01 μm to about 20 μm. 
     
     
         6 . The solid-state electrochemical cell of  claim 1 , wherein the cathode comprises cathode active material particles coated with between about 0.2 and about 5 nm of material. 
     
     
         7 . The solid-state electrochemical cell of  claim 6 , wherein the particles are coated with the material using atomic layer deposition techniques. 
     
     
         8 . The solid-state electrochemical cell of  claim 6 , wherein material comprises aluminum oxide, zirconium oxide, titanium oxide, or any combination thereof. 
     
     
         9 . The solid-state electrochemical cell of  claim 6 , wherein the coated cathode is heat treated at a temperature between 250° C. and 600° C. 
     
     
         10 . The solid-state electrochemical cell of  claim 6 , wherein the cathode is heat treated in a reducing atmosphere comprising one or more of argon, nitrogen, and hydrogen. 
     
     
         11 . The solid-state electrochemical cell of  claim 6 , wherein the cathode is heat treated for about 1 hr to about 24 hrs. 
     
     
         12 . The solid-state electrochemical cell of  claim 1 , wherein the first electrolyte layer is adjacent the anode and comprises xLi 2 S(1−x)P 2 S 5 , where x is a molar ratio and ranges from about 60 to about 80. 
     
     
         13 . The solid-state electrochemical cell of  claim 1 , wherein the first electrolyte layer comprises particles with size of about 0.5 to about 20 μm. 
     
     
         14 . The solid-state electrochemical cell of  claim 1 , wherein the second electrolyte layer comprises particles with size of about 0.5 to about 20 μm. 
     
     
         15 . The solid-state electrochemical cell of  claim 1 , wherein the second electrolyte layer is adjacent the cathode and comprises Li x Ge y P z S 4 , where x, y, z are mole concentrations and range from 2.3<x<4, 0<y<1, and 0<z<1. 
     
     
         16 . The solid-state electrochemical cell of  claim 1 , wherein the second electrolyte layer is heat treated at a temperature between 300° C. and 550° C. 
     
     
         17 . The solid-state electrochemical cell of  claim 1 , wherein the second electrolyte layer is heat treated in a reducing atmosphere comprising one or more of argon, nitrogen, and hydrogen. 
     
     
         18 . The solid-state electrochemical cell of  claim 1 , wherein the second electrolyte layer is heat treated for about 1 hr to about 24 hrs. 
     
     
         19 . A method of forming an electrochemical cell, the method comprising the steps of:
 providing an anode;   providing a cathode comprising electroactive cathode material; and   providing a solid-state electrolyte, wherein the step of providing a solid-state electrolyte comprises the steps of
 preparing a first electrolyte layer composition; 
 preparing a second electrolyte layer composition; and 
 forming a multi-layer electrolyte using the first electrolyte layer and the second electrolyte layer. 
   
     
     
         20 . A battery comprising;
 a housing;   a first terminal;   an anode coupled to the first terminal;   a solid-state electrolyte comprising a first electrolyte layer stable with regard to the anode and a second electrolyte layer stable with regard to the cathode;   a cathode; and   a second terminal coupled to the cathode.