Porous layers within electrochemical cells having directionally oriented channels

Abstract

The following disclosure relates to electrochemical or electrolysis cells and components thereof. More specifically, the following disclosure relates to porous layers and methods of making such porous layers for electrochemical cells. In certain examples, the porous layer includes a plurality of channels that extend through at least 50% of a depth of the porous layer as measured in a direction perpendicular to a plane in which the porous layer is oriented, wherein the porous layer is configured to convey a two-phase mixture of liquid and gas within the electrochemical cell, and wherein each channel of the plurality of channels is configured to facilitate a transfer of gas from the porous layer into an adjacent flow field of the electrochemical cell.

1 . A porous layer of an electrochemical cell, the porous layer comprising:
 a porous composition having a plurality of micropores; and   a plurality of channels having opening diameters that are larger than an average pore diameter of the plurality of micropores,   wherein the plurality of channels extends through at least 50% of a depth of the porous layer as measured in a direction perpendicular to a plane in which the porous layer is oriented,   wherein the porous layer is configured to convey a two-phase mixture of liquid and gas within the electrochemical cell, and   wherein each channel of the plurality of channels is configured to facilitate a transfer of gas from the porous layer into an adjacent flow field of the electrochemical cell.   
     
     
         2 . The porous layer of  claim 1 , wherein the porous layer is a porous transport layer (PTL) configured to be positioned between a membrane and an anode flow field of the electrochemical cell. 
     
     
         3 . The porous layer of  claim 2 , wherein the porous composition comprises a titanium porous sintered powder composition, a titanium mesh composition, a titanium fiber felt composition, or a combination thereof. 
     
     
         4 . The porous layer of  claim 1 , wherein the porous layer is a gas diffusion layer (GDL) configured to be positioned between a membrane and a cathode flow field of the electrochemical cell. 
     
     
         5 . The porous layer of  claim 4 , wherein the porous composition comprises a carbon paper composition, a carbon fiber felt composition, a carbon cloth composition, or a combination thereof. 
     
     
         6 . The porous layer of  claim 1 , wherein the two-phase mixture includes a first flow comprising a liquid flowing away from the flow field toward a membrane of the electrochemical cell and a second flow comprising a gas flowing from the membrane toward the flow field of the electrochemical cell. 
     
     
         7 . The porous layer of  claim 1 , wherein each channel of the plurality of channels extends in a same direction such that the channels of the plurality of channels are parallel with each other. 
     
     
         8 . The porous layer of  claim 7 , wherein an orientation of the plurality of channels within the porous layer is at an angle in a range of 30-90°, and
 wherein the angle is defined between an axis extending through a center of a channel of the plurality of channels and a plane of a membrane of the electrochemical cell. 
 
     
     
         9 . The porous layer of  claim 1 , wherein each channel of the plurality of channels extends through 100% of the depth of the porous layer. 
     
     
         10 . The porous layer of  claim 1 , wherein the porous layer comprises at least one microporous sublayer having no channel of the plurality of channels such that each channel of the plurality of channels extends through less than 100% of the depth of the porous layer, and
 wherein the at least one microporous sublayer is positioned on a surface of the porous layer configured to be positioned adjacent to the flow field, on a surface of the porous layer configured to be positioned opposite from the flow field, or on both surfaces of the porous layer.   
     
     
         11 . The porous layer of  claim 1 , wherein an average opening diameter of the plurality of channels is at least ten times greater than an average pore diameter within the porous composition. 
     
     
         12 . The porous layer of  claim 1 , further comprising:
 a coating composition positioned on a surface of the plurality of channels.   
     
     
         13 . The porous layer of  claim 1 , wherein a first group of channels of the plurality of channels extend in a first direction when the porous layer is positioned between a membrane and the adjacent flow field of the electrochemical cell, and
 wherein at least one second group of channels of the plurality of channels extend in at least one second direction that is different from the first direction when the porous layer is positioned between the membrane and the adjacent flow field.   
     
     
         14 . The porous layer of  claim 13 , wherein the first group of channels and the at least one second group of channels are configured to align with one or more flow field channels of the adjacent flow field. 
     
     
         15 . A method of manufacturing a porous layer, the method comprising:
 casting a slurry composition having a solvent composition onto a substrate to provide a wet tape on the substrate, wherein the slurry composition comprises a metal powder and the solvent composition;   submerging the wet tape on the substrate into a bath solution having a non-solvent composition, wherein a directional exchange takes place in which a portion of the solvent composition within the wet tape is removed from the wet tape via interaction with the non-solvent composition within the bath solution to form a wet tape having a plurality of parallel channels, wherein the solvent composition of the slurry composition comprises a low density solvent having a lower density than the non-solvent composition within the bath solution;   removing the wet tape having the plurality of parallel channels from the bath solution; and   sintering the wet tape having the plurality of parallel channels to form the porous layer.   
     
     
         16 . The method of  claim 15 , wherein the slurry composition further comprises one or more binders and/or one or more additive compositions. 
     
     
         17 . The method of  claim 16 , wherein the one or more binders comprises a plastic or paraffin composition configured to bind and/or coat the metal powder. 
     
     
         18 . The method of  claim 16 , wherein the one or more additive compositions comprises an oxidation-resistant metal composition configured to provide corrosion resistance within the porous layer, and
 wherein the oxidation-resistant metal composition comprises Pt, Au, Ti, Cr, Si, Zr, Y, Nb, Al, TiC, TiN, TiB 2 , or combinations thereof.   
     
     
         19 . The method of  claim 15 , wherein the bath solution further comprises a filler composition configured to coat walls of the plurality of parallel channels during or following the directional exchange of the solvent composition and the non-solvent composition. 
     
     
         20 . The method of  claim 15 , wherein the wet tape on the substrate is submerged into the bath solution at an angle in which a plane of the substrate is not parallel with a plane of the bath solution.