Chromium Poisoning Effects on Performance of (La,Sr)MnO 3 -Based Cathode in Anode-Supported Solid Oxide Fuel Cells

Journal of Power Sources

Lau

et al. 2019

Self Cite

High power density is required to commercialize solid oxide fuel cells for vehicular applications. In this work, high performance of metal supported solid oxide fuel cells (MS-SOFCs) is achieved via catalyst composition, electrode structure, and processing optimization. The full cell configuration consists of a dense ceramic electrolyte and porous ceramic backbones (electrodes) sandwiched between porous stainless steel metal supports. The conventional YSZ electrolyte and backbones are replaced with more conductive and thinner 10Sc1CeSZ ceramics. MS-SOFCs are co-sintered in a single step and subsequently infiltrated with nanocatalysts. Five categories of cathode catalysts are screened in full cells, including: perovskites, nickelates, praseodymium oxide, binary layered composites, and ternary layered composites. Various anode compositions are also tested. The conventional LSM cathode catalyst is replaced with more active Pr6O11 and the Ni content of the SDC-Ni anode is increased. The resulting cells achieve a peak power of 1.56, 2.0, and 2.85 W cm-2 at 700, 750, and 800 °C, respectively, with 3%H2O/H2 as fuel and 2 cathode exposed to air. Multiple cells show reproducible performance (Pmax=1.50 ± 0.06 W cm-2) and OCV (1.10 ± 0.02 V). The performance is further increased with cathode exposed to pure oxygen (2.0 W cm-2 at 700 °C).

Section: Introductionmentioning

confidence: 99%

High performance metal-supported solid oxide fuel cells with infiltrated electrodes

Dogdibegovic

Journal of Power Sources

Lau

et al. 2019

Self Cite

“…The cell activation procedure is described in prior work. 15 After the cell had equilibrated at open circuit voltage (OCV) for 48 h, the initial voltage versus the current density (V-I) curve was measured. After the initial measurement, the cell was operated at a constant current density of 0.5 A cm À2 for 120 h, and the galvanostatic operation of the cell was interrupted only to obtain voltage versus current density measurements every 24 h. During each measurement session, the V-I curves were obtained using two different oxidizing atmospheres, which were dry air (21% oxygen) and 100% oxygen.…”

Section: Full-cell Testingmentioning

confidence: 99%

“…Figure 4a and c shows the V-I curves and power density versus current density (P-I) curves for a complete single SOFC (henceforth referred to as a ''full-cell'' to distinguish it from the previously discussed half-cells), comprising an LNO cathode, measured every 24 h for a total duration of 120 h. These results are compared with the V-I and P-I curves (Fig. 4b, d) for an LSM-YSZ full-cell, which is run under identical conditions by Wang et al 15 For the LNO full-cell, the power density improved every day.…”

Section: Half-cell Testingmentioning

confidence: 99%

“…The main compounds formed through reaction with Cr-vapor phase species and the aforementioned cathodes, leading to degradation, are SrCrO 4 , Cr 2 O 3 and (Cr,Mn) 3 O 4 . [13][14][15] Thus, new Sr and Mnfree cathodes are desirable. Komatsu et al 16 investigated the effect of chromium poisoning on perovskite-structured LaNi 0.6 Fe 0.4 O 3 (LNF) as a cathode material and found that the cathodic overpotential of LNF was not a function of the presence of chromium.…”

Section: Introductionmentioning

confidence: 99%

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Improved Tolerance of Lanthanum Nickelate (La2NiO4+δ) Cathodes to Chromium Poisoning Under Current Load in Solid Oxide Fuel Cells

Gong

Banner

et al. 2019

JOM

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Lanthanum nickelate, La 2 NiO 4+d (LNO), is studied as a cathode material for use in solid oxide fuel cells with the objective of mitigating chromium poisoning. Under current load, both electrochemical and chemical reactions cause chromium poisoning, and high current density and humidity accelerate the poisoning. However, compared with a standard strontium-doped lanthanum manganite cathode, the LNO cathode has a much higher tolerance for chromium poisoning. This can be ascribed to a greatly reduced chromium deposition in LNO.

“…In both PCFC and PCEC cases, one side of the interconnect is exposed to high steam content in an oxidizing environment (especially in the case of electrolysis), which may result in rapid degradation of the interconnect at intermediate temperatures. For conventional SOFC/SOEC stacks, the interconnect and its coating materials have been extensively developed [21][22][23][24][25][26][27][28][29][30][31]. At present, ferritic stainless steel alloys are the most popular choice for intermediate temperature (approximately 600 to 800 °C) SOFC interconnects or substrates, due to low manufacturing cost, suitable oxidation rate, close thermal expansion match with SOFC components, and high electrical and thermal conductivity [28,[32][33][34][35][36].…”

Section: Introductionmentioning

confidence: 99%

Ferritic stainless steel interconnects for protonic ceramic electrochemical cell stacks: Oxidation behavior and protective coatings

International Journal of Hydrogen Energy

Sun

Choi

et al. 2019

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Protonic ceramic fuel or electrolysis cells (PCFC/PCEC) have shown promising performance at intermediate temperatures. However, these technologies have not yet been demonstrated in a stack, hence the oxidation behavior of the metallic interconnect under relevant operating environments is unknown. In this work, ferritic stainless steels 430 SS, 441 SS, and Crofer 22 APU were investigated for their use as interconnect materials in the PCFC/PCEC stack. The bare metal sheets were exposed to a humidified air environment in the temperature range from 450 °C to 650 °C, to simulate their application in a PCFC cathode or PCEC anode. Breakaway oxidation with rapid weight gain and Fe outward diffusion/oxidation was observed on all the selected 2 stainless steel materials. A protective coating is deemed necessary to prevent the metallic interconnect from oxidizing.To mitigate the observed breakaway oxidation, state-of-the-art protective coatings, Y2O3, Ce0.02Mn1.49Co1.49O4, CuMn1.8O4 and Ce/Co, were applied to the stainless steel sheets and their oxidation resistance was investigated. Dual atmosphere testing further validated the effectiveness of the protective coatings in realistic PCFC/PCEC environments, with a hydrogen gradient across the interconnect. Several combinations of metal and coating material were found to be viable for use as the interconnect for PCFC/PCEC stacks. electrolyzers for high temperature water splitting and for co-electrolysis of CO2 and H2O [9][10][11][12].To split water, steam is supplied to the oxygen electrode of the PCEC and dry hydrogen is produced in the fuel electrode, so removal of steam from hydrogen is not needed, and electrochemical compression of H2 can be achieved [4,5]. For co-electrolysis of CO2 and H2O, the lower operating temperature of PCECs favors in-situ Fischer-Tropsch reactions [13], which are the rate-controlling reactions for co-electrolysis in solid oxide electrolyzer cells (SOEC) [14].The lower operating temperature further allows the use of less expensive interconnect and balance-of-plant (BoP) materials, resulting in lower manufacturing costs [15].Although protonic ceramic cell technology has shown great promise, most of the research and development efforts have focused only on the single cell level [1,2,4,7,[16][17][18][19]. Recently, researchers from South Korea demonstrated a scaled-up (5 × 5 cm 2 ) single protonic ceramic fuel cell that showed exciting high initial performance at intermediate temperatures [20]. Up to now, however, stack development of protonic ceramic cells has not been reported. Much work is still needed to realize large-scale application of protonic ceramic cell stacks.To implement protonic ceramic cells at a stack/system scale, it is important to select interconnect materials that are compatible with PCFC/PCEC operating atmospheres and temperatures. For PCFC, one side of the interconnect is exposed to a fuel-water mixture (water is needed for internal reforming), and the other side is exposed to air and generates humidity (humidity is present becau...