| Solid oxide fuel cell（SOFC）is an energy conversion device that directly converts chemical energy into electrical energy.SOFC has the characteristics of full solid-state structure,high working temperature,and high efficiency in cogeneration utilization,and has broad application prospects.Expanding the electrochemical reaction area near the interface is an effective method to improve the electrochemical performance of SOFCs.3D printing can prepare substrates with a certain surface structure and increase the contact area of the electrode electrolyte interface,thereby improving the cell output performance.Compared with other printing technologies,direct-write printing（DIW）technology has the advantages of not requiring heat treatment during the printing process,being able to print colored anodic paste,and forming a corrugated structure on the surface of the blank after printing.Therefore,direct-write printing technology is used to prepare the anode substrate,and the corrugated structure formed on the surface of the substrate is used to increase the contact area of the anode electrolyte interface.In addition,the experiment of preparing anode supported SOFCs by direct-write printing was combined with a multi physical field coupling model to explore the influence of surface structure of anode substrate on cell performance and the reasons behind it.The research content and results of this paper are as follows:（1）The key to preparing SOFC by direct-write printing is the printing of the anode substrate.The paper first examined the rheological properties and stability of the slurry to determine its printability.The results show that the prepared anode slurry with solid loading of 45-60 wt%exhibits shear thinning characteristics at 20oC,and a high shear rate is conducive to the extrusion of the slurry;at different temperatures and shear times,the apparent viscosity of the slurry does not change accordingly and has good stability;The apparent viscosity decreases with the decrease of the solid loading slurry.The printing process is conducive to the extrusion of the slurry under high shear rate stress,and the slurry can maintain a solid state,thus maintaining the shape of the printing body.The anode slurry has printability within a stress range of 1-103 Pa.（2）Electrochemical performance is an important indicator for evaluating the quality of a cell.The effect of anode substrates prepared with different solid loading slurries on the electrochemical performance of cells was investigated.The results showed that the maximum power density（MPD）of SOFC prepared with 60 wt%solid loading slurry could reach 525.80 m W?cm-2 at 850oC,while the SOFC prepared with 45 wt%solid loading slurry was only 283.28 m W?cm-2.By adding an anode functional layer（AFL）to improve the performance of SOFC prepared from slurry with a solid loading of 45 wt%,the MPD was significantly improved,reaching 553.80 m W?cm-2.To further improve cell performance,the thickness of the anode substrate is reduced to 0.2 mm,and the MPD can reach 655.72m W?cm-2.Compared with SOFCs assembled with planar anode substrates prepared by dry pressing method,and the corrugated surface anode substrate prepared by direct-write 3D printing method,it increased the effective interface area of SOFC anode-electrolyte by30.29%,improved cell performance by 59.83%,and significantly improved stability.Although the voltage decay rate of both cells was around 0.0016 V/h within 55 h,the anode substrate prepared by direct-write printing increased the electrode-electrolyte contact surface due to the structured surface.After 64 h of stability testing,the voltage of the prepared cell remained above 0.85 V.（3）By establishing a multi physical field coupling model,the influence and reasons of the corrugated surface of the anode substrate on cell performance were further analyzed.The results showed that for the corrugated structure anode substrate with a thickness of 0.6 mm and 0.4 mm,compared with the planar anode substrate,the effective area of the cell was increased by 30.29%,and the final cell performance was improved by 29.94%and 28.17%,respectively.When the corrugated diameter decreased from 0.200 mm to 0.025 mm,and the thickness was 0.6 mm and 0.4 mm,respectively,the maximum power density increased from527.53 m W?cm-2 and 659.21 m W?cm-2 to 620.30 m W?cm-2 and 767.84 m W?cm-2,respectively,and the performance improved by 17.59%and 16.48%,respectively.The simulation results of multiple physical fields indicate that the consumption of hydrogen at the corrugated structure is greater than that of the planar structure,and the heat generated by the reaction is also higher than that of the planar structure,resulting in a higher current density.Moreover,as the diameter of the corrugated structure decreases,the more hydrogen is consumed at the interface,the more heat is generated,and the current density also increases.This indicates that the corrugated surface of the anode substrate can effectively increase the contact area between the anode and electrolyte interface and increase the reaction sites,this significantly improves cell performance. |
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