Electrochemical cell for carbon dioxide conversion with improved carbon dioxide conversion efficiency

Abstract

Disclosed is an electrochemical cell for carbon dioxide conversion with improved carbon dioxide conversion efficiency that changes the type of fuel injected into an anode, the composition of a separator, the type of a cathode catalyst, etc., to improve the carbon dioxide conversion efficiency and reduce the driving voltage of the electrochemical cell.

What is claimed is: 
     
         1 . An electrochemical cell for carbon dioxide conversion comprising:
 an anode comprising an anode catalyst;   a cathode comprising a cathode catalyst; and   a separator interposed between the anode and the cathode and comprising a buffer solution and a cation exchange material,   wherein hydrogen (H 2 ) is supplied to the anode so that an oxidation reaction of the hydrogen occurs at the anode; and   carbon dioxide (CO 2 ) is supplied to the cathode so that a reduction reaction of the carbon dioxide occurs at the cathode.   
     
     
         2 . The electrochemical cell of  claim 1 , further comprising at least one of:
 an anode porous transport layer located on an outer surface of the anode; and   a cathode porous transport layer located on an outer surface of the cathode.   
     
     
         3 . The electrochemical cell of  claim 1 , wherein the buffer solution comprises phosphoric acid (H 3 PO 4 ). 
     
     
         4 . The electrochemical cell of  claim 1 , wherein the buffer solution has a pKa range of 2≤pKa≤5.5. 
     
     
         5 . The electrochemical cell of  claim 1 , wherein the cation exchange material comprises at least one of polybenzimidazole (PBI) and an ion-pair forming material. 
     
     
         6 . The electrochemical cell of  claim 5 , wherein the ion-pair forming material comprises at least one selected from the group consisting of quaternary ammonium coordinated polyphenylene, polynorbornene, polycarbazole, poly(aryl piperidinium)-based on terphenyl (PAP-TP), imidazolium-functionalized poly(pentafluorostyrene), and combinations thereof. 
     
     
         7 . The electrochemical cell of  claim 1 , wherein the separator comprises the buffer solution at a doping level 3 to 15. 
     
     
         8 . The electrochemical cell of  claim 1 , wherein the cathode catalyst comprises a catalyst metal supported on a support. 
     
     
         9 . The electrochemical cell of  claim 8 , wherein the catalyst metal comprises at least one of a single-atom catalyst and a nanoparticle catalyst. 
     
     
         10 . The electrochemical cell of  claim 9 , wherein the single-atom catalyst comprises at least one selected from the group consisting of nickel (Ni), iron (Fe), cobalt (Co), and combinations thereof. 
     
     
         11 . The electrochemical cell of  claim 9 , wherein the nanoparticle catalyst comprises gold (Au). 
     
     
         12 . The electrochemical cell of  claim 8 , wherein:
 the support comprises a carbon-based support; and   the carbon-based support comprises at least one selected from the group consisting of carbon black, carbon nanotubes, graphite, graphene and combinations thereof.   
     
     
         13 . The electrochemical cell of  claim 8 , wherein the support comprises a nitrogen-doped support. 
     
     
         14 . The electrochemical cell of  claim 1 , wherein the cathode comprises a binder configured to adjust cation conductivity of the cathode. 
     
     
         15 . The electrochemical cell of  claim 14 , wherein the binder comprises at leaset one selected from the group consisting of poly(2,3,5,6-tetrafluorostyrene-4-phosphonic acid) (PWN), perfluorinated ionomers, polyvinylpyrrolidone (PVP), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polybenzimidazole (PBI), polystyrene tetramethyl imidazolium chloride and combinations thereof. 
     
     
         16 . The electrochemical cell of  claim 14 , wherein a weight ratio of a support to the binder in the cathode catalyst is 1:0.4 to 1:1.6. 
     
     
         17 . The electrochemical cell of  claim 1 , further comprising a barrier layer interposed between the separator and the cathode to adjust a rate of a hydrogen evolution reaction (HER). 
     
     
         18 . The electrochemical cell of  claim 17 , wherein the barrier layer comprises at least one selected from the group consisting of silicon dioxide (SiO 2 ), aluminum oxide (Al 2 O 3 ), polyvinylpyrrolidone (PVP) and combinations thereof. 
     
     
         19 . The electrochemical cell of  claim 1 , wherein a single product is produced at the cathode, and the single product comprises at least one selected from the group consisting of carbon monoxide (CO), formic acid (HCOOH), ethylene (C 2 H 4 ), propylene (C 3 H 6 ), and alcohol. 
     
     
         20 . The electrochemical cell of  claim 1 , wherein the hydrogen supplied to the anode comprises humidified hydrogen having a relative humidity of 4% or more.