Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production

Duan, Chuancheng; Kee, Robert J.; Zhu, Huayang; Sullivan, Neal P.; Zhu, Liangzhu; Bian, Liuzhen; Jennings, Dylan; O’Hayre, Ryan

doi:10.1038/s41560-019-0333-2

Cited by 533 publications

(410 citation statements)

References 37 publications

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“…A dual atmosphere oxidation study using humidified air and dry hydrogen on opposite sides of 6 the metal further validates the effectiveness of the protective coatings in PCFC/PCEC environments with a hydrogen gradient. The objectives of this study are (1) to illustrate the oxidation behavior of ferritic stainless steels in PCFC/PCEC environments, and (2) to identify material sets from previous SOFC research that are viable for PCFC/PCEC stack development.…”

Section: Introductionmentioning

confidence: 59%

“…Protonic ceramic electrochemical cells (PCEC) that incorporate proton-conducting oxides as electrolyte materials have attracted increasing research attention in recent years. Compared with the oxide-ion conducting electrolytes used in conventional solid oxide fuel/electrolysis cells, proton-conducting oxides possess higher ionic conductivity at an intermediate temperature range (400-600 °C), therefore enabling higher performance of protonic ceramic fuel and electrolysis cells (PCFCs/PCECs) in this temperature range [1][2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

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

Wang

Sun

Choi

et al. 2019

International Journal of Hydrogen Energy

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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...

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Section: Introductionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

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

Wang

Sun

Choi

et al. 2019

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

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“…By further optimizing electrode composition of NdBa 0.5 Sr 0.5 Co 1.5 Fe 0.5 O 5+δ layered perovskite and adopting proper operating condition, electrolysis current density can be improved to 0.6 A cm −2 at 1.4 V at a lower temperature of 550°C 44 . Most recently there have been several H-SOECs developed with high electrolysis performances at reduced temperature, such as 0.5 A cm −2 at 500°C reported by Haile 53 and 0.74 A cm −2 at 1.4 V in O'Hayre's work 54 . The PNC electrode in this study clearly demonstrates one of the best performances, with highest current density at 500~600°C (1.72 A cm −2 at 600°C, 1.44 A cm −2 at 550°C, 0.84 A cm −2 at 500°C, under 1.4 V).…”

Section: Resultsmentioning

confidence: 99%

“…The high effectiveness of PCECs is necessary to convert a high fraction of electrons and water into hydrogen. The Faradaic efficiencies of electrolzyers based on proton conducting electrolytes have been recently reported by several research groups [52][53][54] . Electronic leakage within the electrolyte under direct current voltage becomes severe with increasing temperature and oxygen partial pressure, which can reduce the efficiency.…”

Section: Discussionmentioning

confidence: 98%

Self-sustainable protonic ceramic electrochemical cells using a triple conducting electrode for hydrogen and power production

et al. 2020

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The protonic ceramic electrochemical cell (PCEC) is an emerging and attractive technology that converts energy between power and hydrogen using solid oxide proton conductors at intermediate temperatures. To achieve efficient electrochemical hydrogen and power production with stable operation, highly robust and durable electrodes are urgently desired to facilitate water oxidation and oxygen reduction reactions, which are the critical steps for both electrolysis and fuel cell operation, especially at reduced temperatures. In this study, a triple conducting oxide of PrNi 0.5 Co 0.5 O 3-δ perovskite is developed as an oxygen electrode, presenting superior electrochemical performance at 400~600°C. More importantly, the selfsustainable and reversible operation is successfully demonstrated by converting the generated hydrogen in electrolysis mode to electricity without any hydrogen addition. The excellent electrocatalytic activity is attributed to the considerable proton conduction, as confirmed by hydrogen permeation experiment, remarkable hydration behavior and computations.

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“…A proton-conducting electrolyte membrane as a PCFC's heart transports proton charge carriers with high levels of ionic conductivity compared with those of oxygen-ionic electrolytes of the traditional solid oxide fuel cells (SOFCs), owing to the corresponding high mobility/concentration of protons [6][7][8][9]. This allows the operational temperatures of the FCs to be decreased by~100-300 • C to reach low-(300-500 • C) and intermediate-temperature (500-700 • C) ranges [10][11][12][13]. As a consequence, temperature-determined processes (electrode sintering, material interaction, thermal misbalance, poisoning) occurring in PCFCs become less adverse factors in terms of their effect on overall performance and FC degradation over a long-term period of operation [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

One-Step Fabrication of Protonic Ceramic Fuel Cells Using a Convenient Tape Calendering Method

et al. 2020

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The present paper reports the preparation of multilayer protonic ceramic fuel cells (PCFCs) using a single sintering step. The success of this fabrication approach is due to two main factors: the rational choice of chemically and mechanically compatible components, as well as the selection of a convenient preparation (tape calendering) method. The PCFCs prepared in this manner consisted of a 30 µm BaCe0.5Zr0.3Dy0.2O3–δ (BCZD) electrolyte layer, a 500 μm Ni–BCZD supporting electrode layer and a 20 μm functional Pr1.9Ba0.1NiO4+δ (PBN)–BCZD cathode layer. These layers were jointly co-fired at 1350 °C for 5 h to reach excellent gas-tightness of the electrolyte and porous structures for the supported and functional electrodes. The adequate fuel cell performance of this PCFC design (400 mW cm−2 at 600 °C) demonstrates that the tape calendering method compares well with such conventional laboratory PCFC preparation techniques such as co-pressing and tape-casting.

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Highly efficient reversible protonic ceramic electrochemical cells for power generation and fuel production

Cited by 533 publications

References 37 publications

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

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

Self-sustainable protonic ceramic electrochemical cells using a triple conducting electrode for hydrogen and power production

One-Step Fabrication of Protonic Ceramic Fuel Cells Using a Convenient Tape Calendering Method

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