Fracture-resistant partition comprising solid electrolyte ceramics for electrolytic cells

Abstract

The present invention relates, in a first aspect, to an electrolysis cell E comprising a dividing wall W suitable for use in an electrolysis cell E. The dividing wall W encompasses at least two alkali metal cation-conducting solid-state electrolyte ceramics FA and FB separated from one another by at least one separating element T. Compared to the cases according to the prior art in which the dividing wall W encompasses the solid-state electrolyte in one piece, this arrangement is more flexible and the individual ceramics have more degrees of freedom available in order to react to fluctuations in temperature, for example by shrinkage or expansion. This increases stability with respect to mechanical stresses in the ceramic.The electrolysis cell E encompasses a cathode chamber KK divided by the dividing wall W from the adjacent chamber, which is a middle chamber KM of the electrolysis cell E.In a second aspect, the present invention relates to a process for producing an alkali metal alkoxide solution in the electrolysis cell E according to the first aspect of the invention.

1 . An electrolysis cell E < 1 > comprising
 at least one anode chamber K A  < 11 > having at least one inlet Z KA  < 110 >, at least one outlet A KA  < 111 >, and an interior I KA  < 112 > comprising an anodic electrode E A  < 113 >, 
 at least one cathode chamber K K  < 12 > having at least one inlet Z KK  < 120 >, at least one outlet A KK  < 121 >, and an interior I KK  < 122 > comprising a cathodic electrode E K  < 123 >, 
 and at least one interposed middle chamber K M  < 13 > having at least one inlet Z KM  < 130 >, at least one outlet A KM  < 131 > and an interior I KM  < 132 >, 
 where I KA  < 112 > and I KM  < 132 > are divided from one another by a diffusion barrier D < 14 >, and A KM  < 131 > is connected by a connection V AM  < 15 > to the inlet Z KA  < 110 >, such that liquid can be passed from I KM  < 132 > into I KA  < 112 > via the connection V AM  < 15 >, where I KK  < 122 > and I KM  < 132 > are divided from one another by a dividing wall W < 16 > comprising one side S KK  < 161 > having the surface O KK  < 163 > and, opposite the side S KK  < 161 >, a side S A/MK  < 162 > having the surface O A/MK  < 164 >, 
 wherein the dividing wall W < 16 > encompasses at least two alkali metal cation-conducting solid-state electrolyte ceramics F A  < 18 > and F B  < 19 > separated from one another by at least one separating element T < 17 > in such a way that the alkali metal cation-conducting solid-state electrolyte ceramics encompassed by the dividing wall W < 16 > are directly contactable both via the surface O KK  < 163 > and via the surface O A/MK  < 164 >, 
 wherein 
 the alkali metal cation-conducting solid-state ceramics encompassed by the dividing wall W < 16 > directly contact the interior I KK  < 122 > on the S KK  side < 161 > via the surface O KK  < 163 >, and the alkali metal cation-conducting solid-state electrolyte ceramics encompassed by the dividing wall W < 16 > directly contact the interior I KM  < 132 > on the S A/MK  < 162 > side via the surface O A/MK  < 164 >. 
 
     
     
         2 . The electrolysis cell E < 1 > according to  claim 1 , wherein the dividing wall W < 16 > comprises at least four alkali metal cation-conducting solid-state electrolyte ceramics F A  < 18 >, F B  < 19 >, F C  < 28 > and F D  < 29 >. 
     
     
         3 . The electrolysis cell E < 1 > according to  claim 2 , wherein the separating element T < 17 > takes the form of a cross or grid. 
     
     
         4 . The electrolysis cell E < 1 > according to  claim 1 , wherein the separating element T < 17 > comprises a material selected from the group consisting of plastic, glass, wood. 
     
     
         5 . The electrolysis cell E < 1 > according to  claim 1 , wherein the dividing wall W < 16 > comprises a frame element R < 20 >. 
     
     
         6 . The electrolysis cell E < 1 > according to  claim 5 , wherein at least a portion of the separating element T < 17 > is in one-piece form together with at least a portion of the frame element R < 20 >. 
     
     
         7 . The electrolysis cell E < 1 > according to  claim 1 , wherein the alkali metal cation-conducting solid-state electrolyte ceramics encompassed by the dividing wall W < 16 > independently have a structure of the formula M I   1+2w+x-y+z  M II   w  M III   x  Zr IV   2-w-x-y  M V   y  (SiO 4 ) z  (PO 4 ) 3-z ,
 where M I  is selected from Na +  and Li + , 
 M II  is a divalent metal cation, 
 M III  is a trivalent metal cation, 
 M V  is a pentavalent metal cation, 
 the Roman indices I, II, III, IV, V indicate the oxidation numbers in which the respective metal cations exist, 
 and w, x, y, z are real numbers, where 0≤x<2, 0<y<2, 0<w<2, 0≤z<3, 
 and where w, x, y, z are chosen such that 1+2w+x−y+z≥0 and 2−w−x−y≥0. 
 
     
     
         8 . The electrolysis cell E <I> according to  claim 1 , wherein the connection V AM  < 15 > is formed within the electrolysis cell E < 1 >. 
     
     
         9 . A process for producing a solution L 1  < 21 > of an alkali metal alkoxide XOR in the alcohol ROH, where X is an alkali metal cation and R is an alkyl radical having 1 to 4 carbon atoms,
 wherein the following steps (β1), (β2), (β3) that proceed simultaneously are conducted in an electrolysis cell E < 1 > according to  claim 1 : 
 (β1) a solution L 2  < 22 > comprising the alcohol ROH is routed through K K  < 12 >, 
 (β2) a neutral or alkaline, aqueous solution L 3  < 23 > of a salt S comprising X as cation is routed through K M  < 13 >, then via V AM  < 15 >, then through K A  < 11 >, 
 (β3) voltage is applied between E A  < 113 > and E K  < 123 >, 
 which affords the solution L 1  < 21 > at the outlet A KK  < 121 >, with a higher concentration of XOR in L 1  < 21 > than in L 2  < 22 >, 
 and which affords an aqueous solution L 4  < 24 > of S at the outlet A KA  < 111 >, with a lower concentration of S in L 4  < 24 > than in L 3  < 23 >. 
 
     
     
         10 . The process according to  claim 9 , wherein X is selected from the group consisting of Li + , Na + , K + . 
     
     
         11 . The process according to  claim 9 , wherein S is a halide, sulfate, sulfite, nitrate, hydrogencarbonate or carbonate of X. 
     
     
         12 . The process according to  claim 9 , wherein R is selected from the group consisting of methyl and ethyl.