Tunable Thin Liquid/Gas Diffusion Layers for Electrolyzers

Abstract

A liquid/gas diffusion layer (LGDL) 112 for use in a proton exchange membrane electrolyzer cell 100 includes a planar body 120 having first and second surfaces 128, 130 that are separated by a body thickness 126. The body defines 120 a plurality of straight-through, non-interconnected, pores 122 extending through the body thickness 126, between the first and the second surfaces 128, 130. Each pore 122 has a peripheral rim shape 124, a throat area, and is separated from one another by a land length distance. The body has a porosity c that is calculated by dividing a total throat area of the plurality of pores A P by a total surface area of the surface around the pores A H , and where the porosity ratio e is between approximately 0.20 and approximately 0.80.

What is claimed is: 
     
         1 . A liquid/gas diffusion layer for use in a proton exchange membrane electrolyzer cell comprising:
 a planar body having a first surface and a second surface that are separated by a thickness, said body defining a plurality of straight-through, non-interconnected, pores extending through the thickness, between the first surface and the second surface, with each pore having a peripheral rim shape, a throat area, and where each pore is separated from one another by a land length distance; and   wherein said body has a porosity ratio that is calculated by dividing a total throat area of the plurality of pores by a total surface area of the first surface extending around the pores, and where the porosity ratio is between approximately 0.20 and approximately 0.80.   
     
     
         2 . The liquid/gas diffusion layer of  claim 1  wherein the calculated porosity ratio is between approximately 0.25 and approximately 0.35. 
     
     
         3 . The liquid/gas diffusion layer of  claim 2  wherein the calculated porosity ratio is between approximately 0.28 and approximately 0.32. 
     
     
         4 . The liquid/gas diffusion layer of  claim 1  wherein the calculated porosity ratio is between approximately 0.65 and approximately 0.75. 
     
     
         5 . The liquid/gas diffusion layer of  claim 4  wherein the calculated porosity ratio is between approximately 0.68 and approximately 0.72. 
     
     
         6 . The liquid/gas diffusion layer of  claim 1  wherein the peripheral shape of each pore is circular and each pore has a diameter and the diameter is between approximately 10 μm and 800 μm. 
     
     
         7 . The liquid/gas diffusion layer of  claim 6  wherein the diameter is between approximately 200 μm and 600 μm. 
     
     
         8 . The liquid/gas diffusion layer of  claim 7  wherein the diameter is between approximately 350 μm and 450 μm. 
     
     
         9 . The liquid/gas diffusion layer of  claim 1  wherein the peripheral rim shape of a pore is selected from the group consisting of circular, rectangular, square, and triangular. 
     
     
         10 . The liquid/gas diffusion layer of  claim 9  wherein the peripheral shape of each pore is the same shape. 
     
     
         11 . The liquid/gas diffusion layer of  claim 1  wherein the pores are uniformly distributed in a pattern. 
     
     
         12 . The liquid/gas diffusion layer of  claim 1  wherein the thickness of said body is less than 200 μm. 
     
     
         13 . The liquid/gas diffusion layer of  claim 12  wherein the thickness of said body is less than 30 μm. 
     
     
         14 . The liquid/gas diffusion layer of  claim 13  wherein the thickness of said body is approximately 25.4 μm. 
     
     
         15 . The liquid/gas diffusion layer of  claim 1  wherein said body is made of a titanium or titanium alloy material. 
     
     
         16 . The liquid/gas diffusion layer of  claim 1  wherein, when the plurality of pores is filled with air and the first surface is level, a contact angle between a drop of water and the first surface measures between approximately 60 degrees and approximately 85 degrees. 
     
     
         17 . The liquid/gas diffusion layer of  claim 1  wherein one of the first or the second surfaces is coated with a layer of catalyst material. 
     
     
         18 . The liquid/gas diffusion layer of  claim 17  wherein the catalyst material layer is between approximately 3 nm and 20 nm thick. 
     
     
         19 . The liquid/gas diffusion layer of  claim 18  wherein the catalyst material layer is approximately 15 nm thick. 
     
     
         20 . The liquid/gas diffusion layer of  claim 17  wherein the catalyst material layer is Pt. 
     
     
         21 . The liquid/gas diffusion layer of  claim 17  wherein the catalyst material layer is chosen from the group consisting of Ir, IrOx, and IrRuOx. 
     
     
         22 . A proton exchange membrane electrolyzer cell comprising:
 an anode liquid/gas diffusion layer having a planar body having a first surface and a second surface that are separated by a thickness, said body defining a plurality of straight-through, non-interconnected, pores extending through the thickness, between the first surface and the second surface, with each pore having a peripheral shape, a throat area, and where each pore is separated from one another by a land length distance; and   wherein said body has a porosity ratio that is calculated by dividing a total throat area of the plurality of pores by a total surface area of the first surface around the pores, and where the porosity ratio is between approximately 0.20 and approximately 0.80.   
     
     
         23 . The liquid/gas diffusion layer of  claim 20  wherein the peripheral shape of each pore is circular and each pore has a diameter and the diameter is between approximately 10 μm and 800 μm. 
     
     
         24 . The liquid/gas diffusion layer of  claim 20  wherein the peripheral shape of a pore is selected from the group consisting of circular, rectangular, square and triangular. 
     
     
         25 . The liquid/gas diffusion layer of  claim 20  wherein the thickness of said body is less than 200 μm. 
     
     
         26 . The liquid/gas diffusion layer of  claim 20  wherein one of the first or the second surfaces is coated with a layer of catalyst material. 
     
     
         27 . The liquid/gas diffusion layer of  claim 26  wherein the catalyst material layer is Pt. 
     
     
         28 . The liquid/gas diffusion layer of  claim 26  wherein the catalyst material layer is chosen from the group consisting of Ir, IrOx, and IrRuOx.