Development of high-performance silver-based gas-diffusion electrodes for chlor-alkali electrolysis with oxygen depolarized cathodes

Moussallem, Imad; Pinnow, Stefan; Wagner, Norbert; Turek, Thomas

doi:10.1016/j.cep.2011.11.003

Cited by 71 publications

(91 citation statements)

References 20 publications

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“…Previous studies have shown that the highest current densities for the ORR could be achieved with electrolyte concentrations of 5 m. [13] We suggest that process conditions with high concentrations of over 5 m lead to mass transport limitations. [8] Also notable is the sensitivity for pressure, even at low current densities, which is in agreement with the resultso fp revious studies, that mass transport influences ODC losses, [28] even at kinetically controlledc urrent densities. The potentiali ss ensitive to oxygen partial pressure.…”

Section: Parameter Sensitivitiessupporting

confidence: 89%

“…[6] Under these conditions, silver shows the same electrochemical activity as that of ap latinum catalyst. [8] Because the solubility of oxygen in the liquid electrolyte is poor due to the high ionic concentrationa nd temperature, the attainedh igh current densities are presently not explainable. [8] Because the solubility of oxygen in the liquid electrolyte is poor due to the high ionic concentrationa nd temperature, the attainedh igh current densities are presently not explainable.…”

Section: Introductionmentioning

confidence: 99%

“…[10] The electrochemistryo fo xygen in concentrated NaOH electrolyte was evaluated by Zhang et al [11] Later Pinnow et al presented am odel that describes the stationary performance of ODCs under various working conditions. [8] Clausmeyer et al performed examinationsw ith different NaOH concentrations in the electrolyte. [8] Clausmeyer et al performed examinationsw ith different NaOH concentrations in the electrolyte.…”

Section: Introductionmentioning

confidence: 99%

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Processes and Their Limitations in Oxygen Depolarized Cathodes: A Dynamic Model‐Based Analysis

2019

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Oxygen depolarized cathodes (ODCs) are key components of alkaline fuel cells and metal–air batteries or of chlor‐alkaline electrolysis, but suffer from limited oxygen availability at the reaction zone. Dynamic analysis is a highly suitable approach to identify the underlying causes, especially the limiting steps and process interactions in such gas diffusion electrodes. Herein, a one‐dimensional, dynamic, three‐phase model for analyzing the oxygen reduction reaction in silver‐based ODCs is presented. It allows for a detailed evaluation of the electrochemical reaction, the mass transport processes, and their interaction. The model also reveals that the depletion of reactant oxygen in the liquid electrolyte is caused by the current‐dependent change of the gas–liquid equilibrium as the limiting subprocess. The phase equilibrium, in turn, depends on the slow mass transport of water and hydroxide ions in the liquid phase. Key parameters are the location or size of the gas–liquid interface within the electrode. Profiles of local concentrations and partial pressures of different species reveal a steep gradient of oxygen in the liquid phase, but no limitation in oxygen mass transport in the gas phase. Dynamic simulations with potential steps allowed the identification of different time constants to separate overlapping processes. Accordingly, the mass transport of water and hydroxide ions was identified as the slowest process that strongly influenced the dynamic response of all species, including oxygen, and of the current. The characteristic time constant of the mass transport of water and hydroxide ions across the liquid phase within the ODC is determined to be τmt,0.166667emnormalH2normalO ≈0.176 s, whereas the time constant of oxygen mass transport into the reaction zone is several magnitudes smaller: τmt,0.166667emnormalO2 ≈1.70×10−6 s. Finally, a sensitivity analysis confirms that the overall performance is best improved by adjusting mass transport properties in the liquid phase.

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Section: Parameter Sensitivitiessupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Processes and Their Limitations in Oxygen Depolarized Cathodes: A Dynamic Model‐Based Analysis

2019

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“…For cycling experiments, a potassium hydroxide solution (40 wt.%) with 4 wt % dissolved zinc oxide was used. The fabricated anodes were tested using a silver‐based gas diffusion cathode for oxygen consumption (Institute of Chemical and Electrochemical Process Engineering, Clausthal University of Technology) and a nickel mesh for oxygen evolution in a three‐electrode cell with stagnant electrolyte . The electrode gap between the electrodes was 5 mm.…”

Section: Methodsmentioning

confidence: 99%

Multiscale Structured Particle‐Based Zinc Anodes in Non‐Stirred Alkaline Systems for Zinc–Air Batteries

et al. 2018

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Primary zinc–air batteries are well established in the commercial market, but secondary zinc–air batteries still suffer from challenging problems. Multiple charge and discharge cycles result in zinc density migration and the formation of passivating by‐products, which can ultimately change the shape of the zinc anode. This work focuses on the use of zinc particles in combination with highly structured current collectors in a cell with a stagnant alkaline electrolyte. Copper weave and copper foam were used as current collectors. The influences of the zinc particle size, the mass loading and the macroscopic structure of the anodes were characterized. Highly structured electrode designs led to improved discharge and cycling performances. Due to the increased active surface area, the electrodes take advantage of highly distributed zinc deposits. The results reveal that the use of multiscale structures within the zinc anode can be beneficial for further applications.

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“…The EMD using Pt/C GDE as cathode shows a better discharge performance as cathode material of Zn-MnO 2 than the commercial battery grade manganese dioxide [3]. In practice, the GDE is also used in chlor-alkali electrolysis [7][8][9][10], electrolysis of potassium iodine [11], electrolysis of sodium carbonate [12] for saving energy and protecting the environment [13,14], yet the research on their energy-saving mechanisms has not been down in potassium iodine electrolysis and electrolysis of sodium carbonate. Consequently, we first used Pt/C GDE rather than traditional electrode as cathode for manganese dioxide electrodeposition in strong acid MnSO 4 media (30 g/dm 3 H 2 SO 4 and 120 g /dm 3 MnSO 4 ) and we further undertook research on its energy-saving mechanism in strong acid MnSO 4 media (30 g/dm 3 H 2 SO 4 and 120 g /dm 3 MnSO 4 ).…”

Section: Introductionmentioning

confidence: 99%

The energy saving mechanism of gas diffusion electrode based on Pt/C catalyst for saving energy and green electrodeposition of manganese dioxide

Tang

HaiBo

et al. 2015

Electrochimica Acta

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Development of high-performance silver-based gas-diffusion electrodes for chlor-alkali electrolysis with oxygen depolarized cathodes

Cited by 71 publications

References 20 publications

Processes and Their Limitations in Oxygen Depolarized Cathodes: A Dynamic Model‐Based Analysis

Processes and Their Limitations in Oxygen Depolarized Cathodes: A Dynamic Model‐Based Analysis

Multiscale Structured Particle‐Based Zinc Anodes in Non‐Stirred Alkaline Systems for Zinc–Air Batteries

The energy saving mechanism of gas diffusion electrode based on Pt/C catalyst for saving energy and green electrodeposition of manganese dioxide

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