ABRASION RESISTANT SOLID OXIDE FUEL CELL ELECTRODE INK
A method for forming a solid oxide fuel cell (SOFC) includes co-firing the anode and cathode electrode layers, which involves placing an unfired anode onto a surface during the cathode print cycle. To avoid damage to the electrolyte and cathode production cycle by the green anode ink, an abrasion resistant ink is used to print the anode electrode layer.
1 . A method of making a solid oxide fuel cell (SOFC), comprising:
forming a first electrode on a first side of a planar solid oxide electrolyte using an abrasion resistant ink, the abrasion resistant ink comprising an abrasion resistant binder which comprises a derivative of methacrylic acid;
drying the first electrode;
forming a second electrode on a second side of the solid oxide electrolyte prior to firing the first electrode;
drying the second electrode; and
firing the first and second electrodes during a single firing step;
wherein the first electrode is an anode and the second electrode is a cathode; and
wherein:
drying the first electrode comprises curing the anode to form interlocking chains or crosslinks in a binder in the abrasion resistant ink such that the binder forms a matrix which contains dispersed anode precursor powder, thereby providing abrasion resistance;
forming the second electrode comprises placing the electrolyte with the dried anode face down on a conveyor and printing the cathode on the second side of the electrolyte; and
firing the first and second electrodes during a single firing step comprises co-firing the anode and the cathode such that the abrasion resistant ink prevents or reduces scuffing of the anode, and prevents or reduces release of loose anode powder into the cathode during cathode forming and drying.
2 . The method of claim 1 , wherein the abrasion resistant ink comprises:
around 60-80 wt. % of a composite powder, wherein the composite powder comprises a metal phase and a ceramic phase;
around 1-10 wt. % of the abrasion resistant binder, wherein the abrasion resistant binder comprises a polymer or polymer precursor;
around 5-35% wt. % of an organic solvent;
zero to less than 2 wt. % of a dispersant; and
zero to less than 1 wt. % of a plasticizer.
3 . The method of claim 1 , wherein forming the first electrode comprises:
printing a first sublayer of the first electrode;
drying the first sublayer;
printing a second sublayer of the first electrode on the first sublayer; and
drying the second sublayer.
4 . The method of claim 2 , wherein the ceramic phase comprises samaria-doped ceria (SDC).
5 . The method of claim 2 , wherein the metal phase comprises a nickel-containing phase that is dispersed throughout the ceramic phase.
6 . The method of claim 2 , wherein drying the first electrode comprises curing the first electrode at 100° C.-150° C. for 2-20 minutes to cure the polymer binder such that the polymer binder forms crosslinks or interlocking chains.
7 . The method of claim 2 , wherein the polymer binder is cross-linked or has interlocking chains prior to the step of drying.
8 . The method of claim 2 , wherein firing the first and second electrodes in a single firing step comprises sintering the first and second electrodes at 1000-1300° C. for 1-6 hours.
9 . The method of claim 2 , wherein the ink contains greater than zero wt. % plasticizer, which comprises butyl benzyl phthalate (BBP).
10 . The method of claim 2 , wherein the ink contains greater than zero wt. % dispersant, which comprises a polymeric surfactant.
11 . The method of claim 1 , further comprising stacking a plurality of unsintered planar solid oxide electrolytes having a dried first electrode on first sides of each of the planar solid oxide electrolytes and a dried second electrode on the second sides of each of the planar solid oxide electrolytes prior to the single firing step.