High-performance anode for solid acid fuel cells prepared by mixing carbon substances with anode catalysts

Tada, Shohei; Tajima, Seiya; Fujiwara, Naoya

doi:10.1016/j.ijhydene.2019.08.100

Cited by 8 publications

(8 citation statements)

References 31 publications

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“…This means that the cell impedance of this frequency range increased significantly during the stability test. Impedance at low frequencies is often associated with the mass transfer processes [32] . Therefore, it is suggested that the performance deterioration of the SAECs was related to gas diffusion properties in the electrodes.…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen Production by Steam Electrolysis in Solid Acid Electrolysis Cells

et al. 2020

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Hydrogen production by steam electrolysis at intermediate temperatures has potential for both the high energy conversion efficiency and the flexible operability suitable for the utilization of renewable energy resources. Employment of proton-conducting solid acid electrolytes at around 200°C is considered promising but has rarely been investigated. Here, steam electrolysis was performed at 160-220°C using a solid acid electrolysis cell (SAEC) composed of a CsH 2 PO 4 /SiP 2 O 7 composite electrolyte and Pt/C electrodes. Hydrogen production was successfully demonstrated with Faraday efficiencies around 80 %. Key factors affecting the SAEC stability were investigated in detail for the first time. It was revealed that a certain part of the electrolyte migrated into the porous anode structure during the operation. The migrated electrolyte prevented the gas diffusion and flooded the Pt/C catalyst layer. It was also found that carbonaceous materials in the anode was oxidized, leading to the decrease in the number of electrochemically active sites. Based on the findings, Pt mesh was employed as an alternative anode. The SAEC with the Pt mesh anode showed superior stability, demonstrating the importance of the anode design. The present work provides a comprehensive view of the stability issues, which is essential for the development of durable and practical SAECs.

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Section: Resultsmentioning

confidence: 99%

“…Impedance at low frequencies is often associated with the mass transfer processes. [32] Therefore, it is suggested that the performance deterioration of the SAECs was related to gas diffusion properties in the electrodes. Figure S2a shows the XRD pattern of as-prepared CsH 2 PO 4 .…”

Section: Impedance Analysismentioning

confidence: 99%

Hydrogen Production by Steam Electrolysis in Solid Acid Electrolysis Cells

et al. 2020

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“…[ 2–4 ] Since then, the Haile group and others have continued to advance solid acid fuel cell (SAFC) technology. [ 5–13 ]…”

Section: Introductionmentioning

confidence: 99%

Comparing Proton Conduction in Potassium and Ammonium Borosulfate—Isostructural Inorganic Polyelectrolytes Exhibiting High Proton Mobility

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Johannes

et al. 2022

Adv Energy and Sustain Res

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A scalable new method for the synthesis of borosulfate compounds in sulfuric acid providing control over product crystallite size is reported as an alternative to traditional methods requiring slow growth from oleum. This new synthetic approach is used to prepare three isostructural, 1D borosulfates: one containing only ammonium cations, another containing only potassium cations, and the third sample with a solid solution of 1:1 ammonium–potassium. Proton conduction in polycrystalline pellets of these borosulfate electrolytes is compared by electrochemical impedance spectroscopy (EIS) and ab initio molecular dynamics (AIMD) simulations. For a given cation (e.g., NH4 +), conductivity decreases by three orders of magnitude with decreasing particle size while maintaining constant activation energy, indicating that proton conduction is not primarily a grain‐boundary process. AIMD simulations show that excess proton mobility in K[B(SO4)2] is in line with that of NH4[B(SO4)2], being a backbone (not cation) mediated process. Although K[B(SO4)2] exhibits higher activation energy (60.6 ± 2.0 kJ mol−1) than NH4[B(SO4)2] (33.8 ± 1.0 kJ mol−1), at 200 °C it achieves comparable conductivity to NH4[B(SO4)2] samples, which is attributable to hydrolytic B–O–H defects being the common source of mobile protons in these materials.

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“…Compared to traditional energy conversion technologies, fuel cells have higher conversion efficiency, lower waste emissions, system compactness, and better environmental benefits [5,6]. Several designs of fuel cells are available including alkaline fuel cell (AFC) [7], solid acid fuel cell (SAFC) [8], phosphoric acid fuel cell (PAFC) [9], and proton-exchange membrane fuel cells (PEMFCs) [10]. Fuel cells can be used in a wide variety of vehicles, like automobiles, buses, boats, motorcycles, and submarines [11].…”

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confidence: 99%