Anisotropic cte lsm for sofc cathode

Abstract

An anisotropic coefficient of thermal expansion (CTE) cathode of a solid oxide fuel cell (SOFC) is formed by placing a layer of perovskite powder between two platens, and sintering the layer while applying pressure to the platens, thereby forming the anisotropic CTE cathode. The perovskite can be lanthanum strontium manganite (LSM).

1 . A cathode of a solid oxide fuel cell, comprising a sintered layer having an anisotropic coefficient of thermal expansion (CTE) defined by an out-of-plane CTE and an in-plane CTE with a difference of at least 1×10 −6 ° C. −1  between the out-of-plane CTE and the in-plane CTE. 
     
     
         2 . The cathode of  claim 1 , wherein the sintered layer is a perovskite. 
     
     
         3 . The cathode of  claim 2 , wherein the perovskite is lanthanum strontium manganite (LSM). 
     
     
         4 . The cathode of  claim 3 , wherein the LSM has an in-plane CTE in a range of between about 10.6×10 −6 ° C. −1  and about 11.8×10 −6 ° C. −1 . 
     
     
         5 . The cathode of  claim 4 , wherein the LSM has an in-plane CTE in a range of between about 11.0×10 −6 ° C. −1  and about 11.4×10 −6 ° C. −1 . 
     
     
         6 . The cathode of  claim 3 , wherein the out-of-plane CTE of the LSM is about 13.0×10 −6 ° C. −1  and the in-plane CTE of the LSM is about 12.0×10 −6 ° C. −1 . 
     
     
         7 . The cathode of  claim 3 , wherein the out-of-plane CTE of the LSM is about 14.0×10 −6 ° C. −1  and the in-plane CTE of the LSM is about 10.6×10 −6 ° C. −1 . 
     
     
         8 . The cathode of  claim 1 , wherein the cathode exhibits a non-linear stress-strain curve at a temperature in a range of between about 20° C. and about 50° C. 
     
     
         9 . A method for forming a low coefficient of thermal expansion (CTE) cathode of a solid oxide fuel cell, comprising the steps of:
 a) placing a layer of perovskite powder between two platens; and   b) sintering the layer while applying pressure to the platens, thereby forming the low CTE cathode.   
     
     
         10 . The method of  claim 9 , wherein the perovskite is lanthanum strontium manganite (LSM). 
     
     
         11 . The method of  claim 9 , wherein the layer has a thickness in a range of between about 0.5 mm and about 4 mm. 
     
     
         12 . The method of  claim 9 , wherein the layer is sintered at a temperature in a range of between about 1200° C. and about 1400° C. for a time period in a range of between about 15 minutes and about 3 hours. 
     
     
         13 . The method of  claim 12 , wherein the layer is sintered at a temperature in a range of between about 1270° C. and about 1290° C. for a time period in a range of between 15 minutes and about one hour. 
     
     
         14 . The method of  claim 9 , wherein the pressure applied to the platens is in a range of between about 0.02 MPa and about 20 MPa. 
     
     
         15 . The method of  claim 14 , wherein the pressure applied onto the platens is in a range of between about 0.02 MPa and about 12 MPa.