Porous Separators Coated With Boron-Containing Species For Electrolyzers

Abstract

This disclosure relates to systems and methods for creating and using separators, containing boron species, that are used in electrolyzers. A disclosed separator for an electrolyzer cell includes a porous substrate having pores which provide a fluid path through the porous substrate from a first side of the porous substrate to an opposite side of the porous substrate, which is formed of one or more hydrophobic polymers or copolymers, and a coating that coats the pores of the porous substrate while maintaining the fluid path, where the coating is formed of an alcohol-containing polymer reacted with a boron-containing species.

1 . A separator for an electrolyzer cell comprising:
 a porous substrate having pores which provide a fluid path through the porous substrate from a first side of the porous substrate to an opposite side of the porous substrate and formed of one or more hydrophobic polymers or copolymers; and   a coating that coats the pores of the porous substrate while maintaining the fluid path, wherein the coating is formed of an alcohol-containing polymer and a boron-containing species that is reacted with the alcohol-containing polymer;   wherein the boron-containing species is formed of boric acid and a base simultaneously present within the same crosslinking step.   
     
     
         2 . The separator of  claim 1 , wherein:
 the hydrophobic polymers or copolymers are selected from a group consisting of: poly(ethylene), poly(propylene), poly(butylene), poly(butadiene), poly(styrene), poly(siloxanes), poly(vinylfluoride), poly(vinylidenefluoride), poly(tetrafluoroethylene), poly(vinylchloride), poly(hexafluoropropylene), poly(vinylchloride), and poly(chlorotrifluoroethylene).   
     
     
         3 . The separator of  claim 1 , wherein:
 the alcohol-containing polymer is created from one or more monomers selected from a group consisting of: acrylates, methacrylates, styrenes, olefins, vinyls, acrylamides, methacrylamides, epoxides, lactams, and lactones.   
     
     
         4 . The separator of  claim 1 , wherein:
 the boron-containing species is selected from a group consisting of: borax, sodium tetrahydroxyborate, boric acid, sodium tetraborate, sodium tetrahydridoborate, potassium tetrahydroxyborate, potassium tetraborate, potassium tetrahydridoborate, lithium tetraborate, lithium tetrahydroxyborate, lithium tetrahydridoborate boron trifluoride, boron trichloride, boron tribromide, diboron trioxide, and triiodoborane.   
     
     
         5 . The separator of  claim 1 , wherein:
 an extent of the porous substrate measured from the first side to the opposite side is not substantially increased by the alcohol-containing polymer coating.   
     
     
         6 . The separator of  claim 1 , wherein:
 the separator remains porous after coating with the coating.   
     
     
         7 . The separator of  claim 1 , wherein:
 the pores in the porous substrate are between 1 nm and 100 microns in size with a uniform distribution of pores throughout the substrate.   
     
     
         8 . The separator of  claim 1 , wherein:
 the alcohol-containing polymer increases a hydrophilicity of the pores of the porous substrate.   
     
     
         9 . The separator of  claim 1 , wherein:
 the coating increases a hydrophilicity of the pores of the porous substrate.   
     
     
         10 . The separator of  claim 1 , further comprising:
 an electrolyte within the electrolyzer cell, wherein the coating increases the fluid transport of the electrolyte through the pores of the separator.   
     
     
         11 . The separator of  claim 10 , wherein:
 the electrolyte is at least partially aqueous.   
     
     
         12 . The separator of  claim 1 , wherein:
 the alcohol-containing polymer contains at least one section with adjacent hydroxyl groups, and the boron-containing species is bonded to two adjacent hydroxyl groups in the at least one section.   
     
     
         13 . The separator of  claim 12 , wherein:
 the alcohol-containing polymer includes alcohol-containing polymer chains; and   at least a portion of the alcohol-containing polymer chains are crosslinked to each other by the boron-containing species.   
     
     
         14 . The separator of  claim 1 , wherein:
 the alcohol-containing polymer is a copolymer formed of a non-alcohol-containing hydrophobic section and an alcohol-containing hydrophilic section.   
     
     
         15 . The separator of  claim 1 , wherein:
 the boron-containing species were reacted with the alcohol-containing polymer in an aqueous medium.   
     
     
         16 . A method of forming a separator, comprising:
 creating a porous substrate from a hydrophobic homopolymer or copolymer;   submerging the porous substrate into a nonaqueous solvent whereby the pores in the porous substrate are filled with the nonaqueous solvent;   adsorbing an alcohol-containing polymer onto the porous substrate including inside the pores contained therein; and   reacting the alcohol-containing polymer with a boron-containing species.   
     
     
         17 . The method of  claim 16 , wherein:
 the nonaqueous solvent is partially nonpolar;   the alcohol-containing polymer is dissolved in the nonaqueous solvent; and   the adsorbing an alcohol-containing polymer step occurs while submerging the porous substrate in the nonaqueous solvent.   
     
     
         18 . The method of  claim 17 , wherein:
 the nonaqueous solvent is dimethyl sulfoxide.   
     
     
         19 . The method of  claim 16 , wherein:
 the nonaqueous solvent is partially nonpolar;   the method further comprises submerging the porous substrate into a first aqueous solution containing the alcohol-containing polymer; and   the adsorbing an alcohol-containing polymer step occurs while submerging the porous substrate in the first aqueous solution.   
     
     
         20 . The method of  claim 19 , wherein:
 the nonaqueous solvent is isopropyl alcohol.   
     
     
         21 . The method of  claim 16 , wherein:
 the porous substrate is formed of one or more polymers selected from a group consisting of: poly(ethylene), poly(propylene), poly(butylene), poly(butadiene), poly(styrene), poly(siloxanes), poly(vinylfluoride), poly(vinylidenefluoride), poly(tetrafluoroethylene), poly(vinylchloride), poly(hexafluoropropylene), poly(vinylchloride), and poly(chlorotrifluoroethylene).   
     
     
         22 . The method of  claim 16 , wherein:
 the alcohol-containing polymer is created from one or more monomers selected from a group consisting of: acrylates, methacrylates, styrenes, olefins, vinyls, acrylamides, methacrylamides, epoxides, lactams, and lactones.   
     
     
         23 . The method of  claim 16 , wherein:
 the boron-containing species is selected from a group consisting of: borax, sodium tetrahydroxyborate, boric acid, sodium tetraborate, sodium tetrahydridoborate, potassium tetrahydroxyborate, potassium tetraborate, potassium tetrahydridoborate, lithium tetraborate, lithium tetrahydroxyborate, lithium tetrahydridoborate, boron trifluoride, boron trichloride, boron tribromide, diboron trioxide, and triiodoborane.   
     
     
         24 . The method of  claim 16 , wherein:
 the reacting of the alcohol-containing polymer with a boron-containing species step occurs in a second aqueous medium.   
     
     
         25 . An electrolysis reactor comprising:
 an aqueous or gaseous anode area with an aqueous or gaseous oxidation substrate;   an aqueous or gaseous cathode area with an aqueous species or a gaseous species as a reduction substrate; and   a separator separating the anode area and the cathode area while allowing ionic migration between the anode area and cathode area;   wherein: (i) the separator is a polymer having a coating; (ii) the coating is formed of an alcohol-containing polymer and a boron-containing species that is reacted with the alcohol-containing polymer; and (iii) the boron-containing species is formed of boric acid and a base simultaneously present within the same crosslinking step.   
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . The separator of  claim 1 , wherein:
 the pores of the separator remain filled with a liquid after the coating is applied.   
     
     
         29 . The electrolysis reactor of  claim 25 , wherein:
 the pores of the separator remain filled with a liquid after the coating is applied.   
     
     
         30 . The separator of  claim 1 , wherein:
 the separator remains ionically conductive both before and after crosslinking utilizing the boron-containing species.   
     
     
         31 . The electrolysis reactor of  claim 25 , wherein:
 the separator remains ionically conductive both before and after crosslinking utilizing the boron-containing species.