Electrochemical devices based on multiple junction ionic conductive membranes

Abstract

A fuel cell ( 100 ) includes a cation exchange membrane ( 110 ), a first anion exchange membrane ( 120 ) and a second anion exchange membrane ( 130 ). The cation exchange membrane ( 110 ) has a first side and an opposite second side. The first anion exchange membrane ( 120 ) has a first exterior surface and an opposite first interior surface disposed along at least a portion to the first side of the cation exchange membrane ( 110 ). A catalyst ( 140 ) is embedded along the first exterior surface. The second anion exchange membrane ( 130 ) has a second exterior surface and an opposite second interior surface disposed along at least a portion to the second side of the cation exchange membrane ( 110 ). A catalyst ( 142 ) is embedded along the second exterior surface. A stack of fuel cells ( 700 ) include a first fuel cell ( 710 ) with an acidic first anode ( 714 ) that is electrically coupled to an alkaline second cathode ( 722 ) of a second fuel cell ( 720 ).

What is claimed is: 
     
         1 . A stack of fuel cells, comprising:
 a. a first fuel cell, including a first cathode and an oppositely disposed acidic first anode;   b. an second fuel cell spaced apart from the first fuel cell, the second fuel cell including a second anode and an oppositely disposed alkaline second cathode, the alkaline second cathode in electrical communication with the acidic first anode of the first fuel cell; and   c. a fuel channel defined between the acidic first anode of the first fuel cell and the second anode of the second fuel cell.   
     
     
         2 . The stack of  claim 1 , further comprising a first oxidant passage disposed adjacent to the first cathode of the first fuel cell and a second oxidant passage disposed adjacent to the alkaline second cathode of the second fuel cell. 
     
     
         3 . The stack of  claim 1 , wherein:
 a. the acidic first anode of the first fuel cell includes a proton exchange membrane; and   b. the first cathode of the first fuel cell includes a selected one of a proton exchange membrane or an anion exchange membrane.   
     
     
         4 . The stack of  claim 1 , wherein:
 a. the alkaline second cathode of the second fuel cell includes an anion exchange membrane; and   b. the second anode of the second fuel cell includes a selected one of a proton exchange membrane or an anion exchange membrane.   
     
     
         5 . The stack of  claim 1 , wherein each of the acidic first anode, the first cathode, the second anode and the alkaline second cathode include an exterior surface into which a catalyst has been embedded. 
     
     
         6 . The stack of  claim 5 , wherein the catalyst includes particles of a metal supported by carbon. 
     
     
         7 . The stack of  claim 6 , wherein the metal comprises a metal selected from a group consisting of: platinum, palladium, silver, nickel and alloys thereof. 
     
     
         8 . The stack of  claim 5 , wherein the catalyst comprises metal particles coated with enzymes. 
     
     
         9 . The stack of  claim 5 , further comprising a conductive mesh disposed adjacent to at least one exterior surface. 
     
     
         10 . The stack of  claim 9 , wherein the conductive mesh comprises a material selected from a group consisting of: a carbon paper, a carbon cloth, a metal mesh, an alloy and combinations thereof.