Electrode diaphragm electrode assembly for alkaline water electrolysers

Vermeiren, Ph.; Moreels, J. P.; Claes, A.; Beckers, Herman

doi:10.1016/j.ijhydene.2009.09.023

Cited by 28 publications

(18 citation statements)

References 12 publications

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“…Weight measurements ( Table 1) have shown that the pores of the structure are not filled completely, so that improved wetting procedures may lead to even higher conductivities if the unfilled pores are not closed. The measured conductivities are lower in direct comparison to Zirfon, a commercially available diaphragm which has also been used to immobilize KOH by Vermeiren et al [15]. They achieved an area specific resistance of 0.1 Ω·cm 2 at a temperature of 80 °C for a membrane of 600 μm in thickness.…”

Section: Conductivity Of Immobilized Kohmentioning

confidence: 89%

Electrical conductivity measurements of aqueous and immobilized potassium hydroxide

Allebrod

Chatzichristodoulou

Mollerup

et al. 2012

International Journal of Hydrogen Energy

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It is important to know the conductivity of the electrolyte from a alkaline electrolysis cell at a given temperature and concentration to reduce the polarization loss during electrolysis through optimal cell and system design. The conductivity of aqueous KOH at elevated temperatures and high concentrations was investigated using the van der Pauw method in combination with electrochemical impedance spectroscopy (EIS). Conductivity values as high as 2.7 S·cm -1 for 35 wt%, 2.8 S·cm -1 for 45wt%, and 2.8 S·cm -1 for 55 wt% concentrated aqueous solutions were measured at 200 °C. Micro-and nano-porous solid pellets were produced and used to immobilize aqueous KOH solutions. These are intended to operate as ion-conductive diaphragms (electrolytes) in alkaline electrolysis cells, offering high conductivity and corrosion resistance. The conductivity of immobilized KOH has been determined by the same method in the same temperature and concentration range. Conductivity values as high as 0.67 S·cm -1 for 35 wt%, 0.84 S·cm -1 for 45 wt%, and 0.73 S·cm -1 for 55 wt% concentrated immobilized aqueous solutions were determined at 200 °C. Furthermore, phase transition lines between the aqueous and aqueous + gaseous phase of aqueous KOH were calculated as a function of temperature, concentration and pressure in the temperature range of 100-300 °C, for concentrations of 0-80 wt% and at pressures between 1 and 100 bar.

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Section: Conductivity Of Immobilized Kohmentioning

confidence: 89%

Electrical conductivity measurements of aqueous and immobilized potassium hydroxide

Allebrod

Chatzichristodoulou

Mollerup

et al. 2012

International Journal of Hydrogen Energy

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“…To obtain a stable electrode potential and constant gas amount inside the electrode, before starting the measurements the sample was polarized for 30 min by applying cathodic current of 100 mA cm À2 [1,5]. After that the potential of the electrode was measured stepwise for 5 min at each current density, starting at 600 mA cm À2 .…”

Section: Cathode Electrodesmentioning

confidence: 99%

“…For CoNiMoW the appropriate electronic structure causes the decrease for the HER overpotential. In contrast to the AWE [1] the AAEMWEs work at lower temperatures because of the low stability of the commercially available membrane. Therefore the highest temperature at which the cathodes were tested was 60 C (Fig.…”

Section: Cathode Electrodesmentioning

confidence: 99%

“…In order to do this, there have to be developed new anion conducting membranes and a new type of current collectors e substrates with a distinct and well developed porous surface [1,2] covered with multiple component non-precious metal catalysts [3,4]. In one previous work we presented the three alloys NiWTiO x , CoMn and CoNiMoW and their positive effect on the Hydrogen Evolution Reaction (HER) [5].…”

Section: Introductionmentioning

confidence: 99%

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Development and testing of an anion exchange membrane electrolyser

Manolova

Schoeberl

Freudenberger

et al. 2015

International Journal of Hydrogen Energy

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“…The separator showed a low gas crossover, and the hydrogen contents in the anode did not reach the operational limits of 2 vol.% at a current density above 50 mA cm −2 . The 85 wt.% ZrO 2 /15 wt.% PSU composite separator showed a low ionic resistance of approximately 3.55 Ω· m and a high bubble point pressure of 7 bar . Sulphonated poly‐ether‐ether‐ketone (SPEEK) porous diaphragms have a bubble point pressure of 3 bar, a cell voltage of approximately 2.5 V (2.47 V, Zirfon PERL separator), and H 2 contents in the anode of 0.103% (0.214%, Zirfon PERL separator) at 0.4 A cm −2 .…”

Section: Introductionmentioning

confidence: 99%

The synthesis of a Zirfon‐type porous separator with reduced gas crossover for alkaline electrolyzer

et al. 2019

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Summary The rapid expansion of renewable energy sources presents a great challenge to balance the electric grid due to their intermittent and volatile nature. The surplus energy generation cannot be used or sold so that it is curtailed in order to maintain the grid balance. The excess power can be converted into a gaseous energy carrier, hydrogen via power‐to‐gas technology. Alkaline water electrolysis can be operated in a dynamic mode using renewable energy sources on a large scale. However, the risk of gas crossover across a porous separator rapidly increases when the electrolyzer operates at a low partial load or at high pressure, leading to efficiency loss and a safety issue. The commercial porous separator Zirfon PERL, which is composed of 85 wt.% zirconia nanoparticles and 15 wt.% polysulfone, exhibits a satisfactory bubble point pressure performance of approximately 2.5 bar and ionic resistance of 0.3 Ω cm2. However, the Zirfon PERL separator exhibits a high hydrogen permeability value of 20 × 10−12 mol cm−1 bar−1 sec−1 due to its large average pore size of 130 nm, resulting in a limited dynamic range of the electrolyzer. Therefore, it is necessary to develop a porous separator with reduced gas crossover. In this study, we synthesize a porous ZrO2/polysulfone composite separator by varying the amount of ZrO2 (75‐85 wt.%) via the film‐casting method. The 75 wt.% ZrO2/25 wt.% polysulfone composite separator, which contains a low amount of ZrO2, shows a high bubble point pressure of 3.8 bar, a low ionic resistance of 0.3 Ω cm2, and are reduced hydrogen permeability of 4.2 × 10−12 mol cm−1 bar−1 sec−1 compared with that of Zirfon PERL separator. The enhanced performance of this separator is attributed to the reduced average pore size of around 70 nm and high surface wettability with a contact angle of 75°. This result will help alkaline electrolyzer systems be operated as more controllable loads.

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Electrode diaphragm electrode assembly for alkaline water electrolysers

Cited by 28 publications

References 12 publications

Electrical conductivity measurements of aqueous and immobilized potassium hydroxide

Electrical conductivity measurements of aqueous and immobilized potassium hydroxide

Development and testing of an anion exchange membrane electrolyser

The synthesis of a Zirfon‐type porous separator with reduced gas crossover for alkaline electrolyzer

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