Solid-electrolyte-type electrolyzer and method for maintaining same

Abstract

A solid-electrolyte electrolytic device may be excellent in operation rate and have device life without stopping a CO 2 reduction reaction. A solid-electrolyte electrolytic device may include: a cathode that performs a reduction reaction; an anode that constitutes one pair of electrodes together with the cathode; an electrolytic solution that is in contact with the anode and supports an oxidation-reduction reaction; a solid electrolyte that is disposed between the cathode and the anode; and a refresh unit that supplies a recovery liquid for diluting or replacing the electrolytic solution to the anode to remove a salt precipitated between the cathode and the solid electrolyte, the recovery liquid being a solution with a lower concentration of a cation identical to a cation included in the salt than the electrolytic solution.

1 . A solid-electrolyte electrolytic device, comprising:
 a cathode that configured to perform a reduction reaction;   an anode that constitutes one pair of electrodes together with the cathode;   an electrolytic solution that is in contact with the anode and is configured to support an oxidation-reduction reaction;   a solid electrolyte that is disposed between the cathode and the anode; and   a refresh unit configured to supply a recovery liquid for diluting or replacing the electrolytic solution to the anode to remove a salt precipitated between the cathode and the solid electrolyte,   wherein the recovery liquid is a solution with a lower concentration of a cation identical to a cation comprised in the salt than the electrolytic solution.   
     
     
         2 . The device of  claim 1 , wherein the electrolytic solution is
 an aqueous solution comprising KHCO 3 , NaHCO 3 , K 2 CO 3 , Na 2 CO 3 , NaCl, KCl, NaOH, and/or KOH,   a phosphate buffer, or   a borate buffer.   
     
     
         3 . The device of  claim 1 , wherein the recovery liquid is
 an aqueous solution comprising KHCO 3 , NaHCO 3 , K 2 CO 3 , Na 2 CO 3 , NaCl, KCl, NaOH, and/or KOH,   water,   a phosphate buffer, or   a borate buffer.   
     
     
         4 . A method for removing a precipitated salt that is precipitated on a cathode of the solid-electrolyte electrolytic device of  claim 1 , the method comprising:
 separating the cathode and the precipitated salt.   
     
     
         5 . A maintenance method for a solid-electrolyte electrolytic device, the method comprising:
 supplying a recovery liquid from a refresh unit to an anode, thereby diluting or replacing an electrolytic solution with the recovery liquid; and   removing a salt by continuously applying a voltage between a cathode and an anode,   wherein the solid-electrolyte electrolytic device comprises:   the cathode that performs a reduction reaction;   the anode that constitutes one pair of electrodes together with the cathode;   the electrolytic solution that is in contact with the anode and supports an oxidation-reduction reaction;   a solid electrolyte that is disposed between the cathode and the anode; and   the refresh unit that supplies a recovery liquid for diluting or replacing the electrolytic solution to the anode to remove the salt precipitated between the cathode and the solid electrolyte,   wherein the recovery liquid is a solution with a lower concentration of a cation identical to a cation comprised in the salt than the electrolytic solution.   
     
     
         6 . The device of  claim 2 , wherein the recovery liquid is
 an aqueous solution comprising KHCO 3 , NaHCO 3 , K 2 CO 3 , Na 2 CO 3 , NaCl, KCl, NaOH, and/or KOH,   water,   a phosphate buffer, or   a borate buffer.   
     
     
         7 . A method for removing a precipitated salt that is precipitated on a cathode of the solid-electrolyte electrolytic device of  claim 2 , the method comprising:
 separating the cathode and the precipitated salt.   
     
     
         8 . A method for removing a precipitated salt that is precipitated on a cathode of the solid-electrolyte electrolytic device of  claim 3 , the method comprising:
 separating the cathode and the precipitated salt.   
     
     
         9 . A method for removing a precipitated salt that is precipitated on a cathode of the solid-electrolyte electrolytic device of  claim 6 , the method comprising:
 separating the cathode and the precipitated salt.   
     
     
         10 . The device of  claim 1 , wherein the electrolytic solution comprises KHCO 3 , NaHCO 3 , K 2 CO 3 , Na 2 CO 3 , NaCl, KCl, NaOH, and/or KOH. 
     
     
         11 . The device of  claim 1 , wherein the electrolytic solution comprises a phosphate buffer. 
     
     
         12 . The device of  claim 1 , wherein the electrolytic solution comprises a borate buffer.