Patent ID: 8158304
Filing Date: 2012-04-17
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. A formulation and application process for nano-scale electrolyte suspension for the fabrication of a solid oxide fuel cells-membrane electrolyte assembly (SOFC-MEA) comprising the steps of: (1) A formulation and a fabrication process for nano-scale electrolyte suspension comprising steps: Step a: using a hydrothermal co-precipitation process to prepare a nano-scale YSZ ceramic powders with 100% cubic crystal structure; Step b: mixing the nano-scale YSZ ceramic powder 10˜50% by weight, PAA 0.01˜1% by weight, PVA 0.1˜5% by weight, octanol 0.005˜1% by weight, and deionized water as solvent; Step c: preparing the nano-scale electrolyte suspension is as follows: the mixture from Step b is subject to homogenization by grinding/dispersing treatment for 1˜24 hours with ZrO (2) The process to apply the nano-scale YSZ suspension to fabricate SOFC-MEA is as follows: A. The airtight/fully dense electrolyte layer fabrication process comprising steps: Step d: fixing the center of an anode substrate onto spin coater, test running at 30 rpm to assure the substrate is firmly placed on the spin coater; Step e: The spin coating process has three stages: (1) putting a suitable amount of suspension onto the anode substrate surface and running the spin coater at 150˜800 rpm for 6 seconds; (2) distributing the suspension evenly onto the anode substrate surface and running the spin coater at 1000˜2000 rpm for 30˜60 seconds; (3) putting the suspension onto the anode substrate surface and running the spin coater at 2000˜3000 rpm for 6 seconds, and spinning off the residual solvent to obtain green tape electrolyte half-cell; Step f: putting the coated half-cell in an oven at 80° C. and repeating Step d and Step e for about eight times to complete the electrolyte coating process; Step g: putting the completed half-cell in a high-temperature furnace for sintering at 1450° C. and holding it at 1390° C. for 15 hours while the temperature increase rate is 0.5˜3° C./min and the temperature decrease rate is 1˜3° C./min, and after sintering, a ceramic half-cell of airtight/fully dense YSZ electrolyte layers is obtained; B. SOFC-MEA fabrication process at least comprising steps: Step h: fixing the half-cell onto a screen printer by vacuum operation, and adjusting it to a suitable coating thickness, scraper pressure and scraper speed; Step i: putting a suitable amount of LSM paste on the screen and running the scraper for several times to coat the paste evenly onto the half-cell, and leaving and setting the half-cell in an oven at 80° C.; Step j: putting the solid oxide fuel cell with completed cathode coating in a high-temperature furnace for sintering at 1100° C. for 3 hours, while the temperature increase rate and the temperature decrease rate are both 1° C./min., thus a solid oxide fuel cell-membrane electrode assembly is obtained; and Step k: conducting SEM microstructure analysis and electrolyte gas permeability test for the completed SOFC-MEA.