High-differential-pressure water electrolysis cell and method of operation

Abstract

An electrolysis cell includes an anode, a cathode and a high-differential-pressure water electrolysis bilayer membrane disposed between the anode and the cathode. The high-differential-pressure bilayer membrane includes a platinum-impregnated ion-exchange membrane layer and an untreated ion-exchange membrane layer. The untreated ion-exchange membrane layer is disposed between the anode and the platinum-impregnated ion-exchange membrane layer.

1 . An electrolysis cell comprising:
 an anode;   a cathode; and   a high-differential-pressure water electrolysis bilayer membrane disposed between the anode and the cathode, the high-differential-pressure water electrolysis bilayer membrane comprising:
 a platinum-impregnated ion-exchange membrane layer; and 
 an untreated ion-exchange membrane layer disposed between the anode and the platinum-impregnated ion-exchange membrane layer. 
   
     
     
         2 . The electrolysis cell of  claim 1 , wherein the untreated ion-exchange membrane layer is thicker than the platinum-impregnated ion-exchange membrane layer. 
     
     
         3 . The electrolysis cell of  claim 1 , wherein a ratio of a platinum-impregnated ion-exchange membrane layer thickness to a high-differential-pressure water electrolysis bilayer membrane thickness is between about 0.002 to about 0.999. 
     
     
         4 . The electrolysis cell of  claim 3 , wherein the ratio of the platinum-impregnated ion-exchange membrane layer thickness to the high-differential-pressure water electrolysis bilayer membrane thickness is between about 0.002 and about 0.8 
     
     
         5 . The electrolysis cell of  claim 3 , wherein the ratio of the platinum-impregnated ion-exchange membrane layer thickness to the high-differential-pressure water electrolysis bilayer membrane thickness is between about 0.004 and about 0.5. 
     
     
         6 . The electrolysis cell of  claim 1 , wherein the platinum-impregnated ion-exchange membrane layer and the untreated ion-exchange membrane layer are hot-pressed together to form a single structure. 
     
     
         7 . The electrolysis cell of  claim 1 , wherein the untreated ion-exchange membrane layer is a chemically-stabilized perfluorocarbon ion-exchange membrane. 
     
     
         8 . The electrolysis cell of  claim 1 , wherein the electrolysis cell is a high-differential-pressure water electrolysis cell that generates oxygen at a pressure up to about 24,821 kilopascals. 
     
     
         9 . The electrolysis cell of  claim 1 , and further comprising:
 a water feed line connected to the cathode.   
     
     
         10 . A method for producing high-purity oxygen, the method comprising:
 feeding water to a cathode of a high-differential-pressure electrolysis cell, the high-differential-pressure cell comprising an anode and a bilayer membrane disposed between the anode and the cathode, the bilayer membrane including a platinum-impregnated ion-exchange membrane layer and an untreated ion-exchange membrane layer, wherein the platinum-impregnated ion-exchange membrane layer is impregnated with platinum which forms catalyst sites in the platinum-impregnated ion-exchange membrane layer;   transporting water from the cathode to the anode across the platinum-impregnated ion-exchange membrane layer and then across the untreated ion-exchange membrane layer;   electrolyzing the water in the anode to produce hydrogen ions, oxygen gas and electrons;   passing the electrons through an exterior circuit to the cathode;   passing the hydrogen ions through the untreated ion-exchange membrane layer and then through the platinum-impregnated ion-exchange membrane layer to the cathode;   combining the hydrogen ions and the electrons to form hydrogen gas in the cathode; and   recombining cross-diffusing hydrogen gas of the cathode and oxygen gas of the anode at the catalyst sites of the platinum-impregnated ion-exchange membrane.   
     
     
         11 . The method of  claim 10 , wherein the anode is configured to operate at pressures up to about 24,821 kilopascals. 
     
     
         12 . The method of  claim 11 , wherein the platinum-impregnated ion-exchange membrane layer and the untreated ion-exchange membrane layer are hot-pressed together to form a single structure. 
     
     
         13 . The method of  claim 12 , wherein a ratio of a thickness of the platinum-impregnated ion-exchange membrane layer to a thickness of the bilayer membrane is between about 0.002 and about 0.999. 
     
     
         14 . The method of  claim 13 , wherein the ratio of the thickness of the platinum-impregnated ion-exchange membrane layer to the thickness of the bilayer membrane is between about 0.002 and about 0.8. 
     
     
         15 . The method of  claim 10 , wherein the platinum-impregnated ion-exchange membrane layer is adjacent the cathode and the untreated ion-exchange membrane layer is adjacent the anode. 
     
     
         16 . A system for producing high-purity oxygen, the system comprising:
 an oxygen anode for producing hydrogen ions, oxygen gas and electrons;   a hydrogen cathode for producing hydrogen gas;   a water feed connected to the cathode for feeding water thereto; and   an electrolysis bilayer ion-exchange membrane comprising:
 a platinum-impregnated ion-exchange membrane layer; and 
 an untreated ion-exchange membrane layer, wherein the bilayer ion-exchange membrane is disposed between the anode and the cathode such that the platinum-impregnated ion-exchange membrane layer is closer to the cathode than to the anode. 
   
     
     
         17 . The system of  claim 16 , wherein a ratio of a thickness of the platinum-impregnated ion-exchange membrane layer to a thickness of the electrolysis bilayer ion-exchange membrane is between about 0.002 to about 0.999. 
     
     
         18 . The system of  claim 16 , wherein the ratio of the thickness of the platinum-impregnated ion-exchange membrane layer to the thickness of the electrolysis ion-exchange bilayer membrane is between about 0.004 and about 0.5. 
     
     
         19 . The system of  claim 16 , wherein the platinum-impregnated ion-exchange membrane layer and the untreated ion-exchange membrane layer are hot-pressed together to form a single structure. 
     
     
         20 . The system of  claim 16 , wherein the platinum-impregnated ion-exchange membrane layer and the untreated ion-exchange membrane layer are separate structures in the bilayer ion-exchange membrane.