Advanced solid acid electrolyte composites

Abstract

Solid acid/surface-hydrogen-containing secondary component electrolyte composites, methods of synthesizing such materials, electrochemical device incorporating such materials, and uses of such materials in fuel cells, membrane reactors and hydrogen separations are provided. The stable electrolyte composite material comprises a solid acid component capable of undergoing rotational disorder of oxyanion groups and capable of extended operation at a wide temperature range and a secondary compound with surface hydrogen atoms, which when intimately mixed, results in a composite material with improved conductivity, mechanical and thermal properties, when compared to pure solid acid compound.

1 . A proton conducting membrane, said membrane comprising: 
 a solid acid component, wherein said solid acid component is capable of conducting protons in a solid state through a superprotonic mechanism;    a secondary component having a plurality of surface hydrogen; and    a plurality of interfaces formed by said solid acid component and said secondary component, wherein said solid acid component and said secondary component interact to form a composite.    
     
     
         2 . The proton conducting membrane of  claim 1 , wherein said plurality of interfaces is formed by hydrogen bonding interactions between said solid acid component and said secondary component.  
     
     
         3 . The proton conducting membrane of  claim 1 , wherein said solid acid component comprises a plurality of solid acid particles.  
     
     
         4 . The proton conducting membrane of  claim 1 , wherein said secondary component comprises a plurality of secondary component particles.  
     
     
         5 . The proton conducting membrane of  claim 1 , wherein the secondary component is selected from the group consisting of an inorganic compound, a polymer, a nanostructure and ceramics.  
     
     
         6 . The proton conducting membrane of  claim 1 , wherein said solid acid component comprises a plurality of solid acid particles and said secondary component comprises a plurality of secondary component particles having a plurality of surface of hydrogen.  
     
     
         7 . The proton conducting membrane of  claim 1 , further comprising a structural binder selected from the group consisting of a polymer, ceramic, glass, a metal, a nanostructure and a mixture thereof.  
     
     
         8 . The proton conducting membrane of  claim 1 , wherein said solid acid component comprises a compound having the formula M a H b (XO t ) c , 
 wherein    M is a cation having a charge from +1 to +4;    X is selected from the group consisting of S, Se, P, As, Si, Ge, V, Cr and Mn; and a, b, t and c are each independently a non-negative real number from 1 to 4.    
     
     
         9 . The proton conducting membrane of  claim 1 , wherein said solid acid component is an eulytite solid acid.  
     
     
         10 . The proton conducting membrane of  claim 1 , wherein said secondary component comprises a compound having the formula M′ d (X′O y ) e *nH 2 O(H f X″O z ) g , wherein 
 M′ is a cation having a charge from +1 to +4;    X′ and X” are each independently selected from the group consisting of S, Se, P, As, Si, Ge;    n and g are each independently a non-negative real number; and    d, e, f, y and z are each independently a non-negative real number from 1 to 4.    
     
     
         11 . The proton conducting membrane of  claim 8 , wherein said secondary component comprises a compound having the formula M′ d (X′O y ) e *nH 2 O(H f X″O z ) g .  
     
     
         12 . The proton conducting membrane of  claim 11 , wherein said solid acid component comprises a compound having the formula CsH 2 PO 4  and said secondary component comprises a compound having the formula LaPO 4 *nH 2 O(H 3 PO 4 ) g .  
     
     
         13 . The proton conducting membrane of  claim 8 , wherein said secondary component is selected from the group consisting of a polymer, a metal and a ceramic.  
     
     
         14 . The proton conducting membrane of  claim 13 , wherein said solid acid is CsH 2 PO 4  and said secondary component is a polymer selected from the group consisting of poly(trimesic acid)s, polybenzimidazoles, polyimidazoles, poly(monododecylphosphate), polyimides, polyamines, polyamides, phosphated tetrafluoroethylene copolymers and sulfonated tetrafluoroethylene copolymers (Nafion®).  
     
     
         15 . The proton conducting membrane of  claim 1 , has a conductivity from about 10 −3  Ω −1  cm −1  to about 0.2 Ω −1  cm −1  in the temperature range from about 130° C. to about 330° C.  
     
     
         16 . The proton conducting membrane of  claim 11 , wherein X, X′ and X″ represent the same element.  
     
     
         17 . The proton conducting membrane of  claim 11 , wherein M is a different cation from M′.  
     
     
         18 . The proton conducting membrane of  claim 1 , further comprising a separate electrically conducting material.  
     
     
         19 . The proton conducting membrane of  claim 18 , wherein the conducting material is selected from the group consisting of a conducting polymer, a metal and a carbon material.  
     
     
         20 . The proton conducting membrane of  claim 1 , wherein said membrane has a proton conductivity of about 10 −5  Ω −1  cm −1  or higher at the temperature of utilization.  
     
     
         21 . A fuel cell system comprising a proton conducting membrane in accordance with  claim 1 , wherein the fuel cell system provides electrical power to an external device.  
     
     
         22 . A proton conducting membrane, said membrane comprising: 
 a plurality of solid acid particles, wherein said plurality of solid acid particles is capable of conducting protons in a solid state through a superprotonic mechanism;    a plurality of secondary component particles having a plurality of surface hydrogen; and    a plurality of interfaces formed by said solid acid component particles and said secondary component particles, wherein said solid acid component and said secondary component interact to form a composite.    
     
     
         23 . The proton conducting membrane of  claim 22 , wherein each particle of said plurality of secondary particles has a dimension from about 5 nm to about 50 μm.  
     
     
         24 . A method for preparing a proton conducting membrane, said method comprising: 
 contacting a solid acid component with a secondary component having a plurality of surface hydrogen under conditions sufficient to generate a composite, wherein said solid acid component interacts with said secondary component to form a plurality of interfaces.    
     
     
         25 . The method of  claim 24 , further comprising contacting a structural binder.  
     
     
         26 . The method of  claim 24 , wherein said plurality of interfaces is formed by hydrogen bonding interactions between said solid acid component and said secondary component.  
     
     
         27 . The method of  24 , wherein said solid acid component is a compound of the formula M a H b (XO t ) c ; and said secondary component is a compound of the formula M′ d (X′O y ) e *nH 2 O(H f X″O z ) g , 
 wherein    M and M′ are each independently a cation having a charge from +1 to +4;    X, X′ and X″ are each independently selected from the group consisting of S, Se, P, As, Si and Ge;    a, b, t, c, d, y, e, f and z are each independently a non-negative real number from 1 to 4; and    n and g are each independently a non-negative real number.    
     
     
         28 . The method of  claim 24 , wherein said solid acid component is a compound of the formula M a H b (XO t ) c ; and said secondary component is selected from the group consisting of a polymer, a metal, ceramic, a carbon material and a nanostructure.  
     
     
         29 . A method of rehydrating a solid acid composite, said method comprising: contacting the solid acid composite of  claim 1  with a water molecule under conditions sufficient for rehydrating.