Comparative analysis of performance of alkaline water electrolyzer by using porous separator and ion-solvating polybenzimidazole membrane

Alam, Afroz; Park, Chungi; Lee, Jaeseung; Ju, Hyunchul

doi:10.1016/j.renene.2020.11.151

Cited by 10 publications

(4 citation statements)

References 40 publications

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“…A constant value of bubble diameter is often chosen for modeling gas evolving electrochemical systems. 23,27,45,46,58,[64][65][66][67] However, as it was pointed out by Hreiz et al 27 it is expected that taking into account the bubbles polydispersity would lead to a more accurate prediction of the hydrodynamics in narrow vertical electrochemical reactors.…”

Section: Bubble Size Distributionmentioning

confidence: 99%

Current and Potential Distribution in Two-Phase (Gas Evolving) Electrochemical Reactors by the Finite Volume Method

Colli

Bisang

2022

J. Electrochem. Soc.

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A solver was developed and implemented in the OpenFOAM framework in order to predict the current distribution in gas evolving electrochemical reactors. The solver takes into account both liquid and gas flows under turbulent conditions and assuming a bubble population balance with a range of bubble sizes. The possibility of coalescence and breakup of bubbles is also considered. The comparison between experimental results of gas fraction and current distribution, from this research and from previous ones, demonstrates that the solver is able to predict the behavior of this kind of electrochemical systems. The model presented is supplied as a free source code.

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Section: Bubble Size Distributionmentioning

confidence: 99%

Current and Potential Distribution in Two-Phase (Gas Evolving) Electrochemical Reactors by the Finite Volume Method

Colli

Bisang

2022

J. Electrochem. Soc.

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“…Thin-film composite (TFC) membranes have recently been shown to perform comparably to ion-exchange membranes with a supporting electrolyte in electrochemical energy conversion systems . Combining an ultrathin selective layer with a highly porous substrate, they serve as an alternative separator that could potentially overcome the trade-off between conductivity and selectivity. , These membranes are much thinner than traditional porous diaphragms which do not require highly concentrated supporting electrolyte and much less expensive than ion-exchange membranes. , One type of TFC membrane, originally developed for use in reverse osmosis (RO) desalination of seawater, was recently shown to have performance similar to that of a cation-exchange membrane (CEM) for hydrogen gas production with a synthetic seawater catholyte. The overpotential at a constant current density of 10–40 mA/cm 2 in an asymmetric seawater electrolyzer using a contained anolyte (1 M NaClO 4 ) that cannot be oxidized at the anode in order to favor the oxygen evolution reaction (OER), and a NaCl catholyte (1 M) had an overpotential similar to that of a CEM in the same system. , The active layer of the TFC membrane retained larger hydrated salt ions but allowed the transport of smaller water ions (protons and hydroxide ions) to balance the charge.…”

Section: Introductionmentioning

confidence: 99%

“…3,27 These membranes are much thinner than traditional porous diaphragms which do not require highly concentrated supporting electrolyte and much less expensive than ion-exchange membranes. 3,28 One type of TFC membrane, originally developed for use in reverse osmosis (RO) desalination of seawater, was recently shown to have performance similar to that of a cation-exchange membrane (CEM) for hydrogen gas production with a synthetic seawater catholyte. The overpotential at a constant current density of 10−40 mA/cm 2 in an asymmetric seawater electrolyzer using a contained anolyte (1 M NaClO 4 ) that cannot be oxidized at the anode in order to favor the oxygen evolution reaction (OER), and a NaCl catholyte (1 M) had an overpotential similar to that of a CEM in the same system.…”

Section: ■ Introductionmentioning

confidence: 99%

Thin-Film Composite Membranes for Hydrogen Evolution with a Saline Catholyte Water Feed

Shi,

Zhou,

Taylor

et al. 2024

Environ. Sci. Technol.

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Hydrogen gas evolution using an impure or saline water feed is a promising strategy to reduce overall energy consumption and investment costs for on-site, large-scale production using renewable energy sources. The chlorine evolution reaction is one of the biggest concerns in hydrogen evolution with impure water feeds. The "alkaline design criterion" in impure water electrolysis was examined here because water oxidation catalysts can exhibit a larger kinetic overpotential without interfering chlorine chemistry under alkaline conditions. Here, we demonstrated that relatively inexpensive thin-film composite (TFC) membranes, currently used for high-pressure reverse osmosis (RO) desalination applications, can have much higher rejection of Cl − (total crossover of 2.9 ± 0.9 mmol) than an anion-exchange membrane (AEM) (51.8 ± 2.3 mmol) with electrolytes of 0.5 M KOH for the anolyte and 0.5 M NaCl for the catholyte with a constant current (100 mA/cm 2 for 20 h). The membrane resistances, which were similar for the TFC membrane and the AEM based on electrochemical impedance spectroscopy (EIS) and Ohm's law methods, could be further reduced by increasing the electrolyte concentration or removal of the structural polyester supporting layer (TFC-no PET). TFC membranes could enable pressurized gas production, as this membrane was demonstrated to be mechanically stable with no change in permeate flux at 35 bar. These results show that TFC membranes provide a novel pathway for producing green hydrogen with a saline water feed at elevated pressures compared to systems using AEMs or porous diaphragms.

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“…This increased gas crossover resulted in a significant reduction in the dynamic range of the electrolyzer [ 45 , 46 ]. Gas crossover can be reduced by increasing the thickness of the porous separator membrane; however, it will also increase the ohmic voltage drop in the electrolyte, resulting in lower energy efficiency [ 47 ]. For that reason, the need of the hour is to develop advanced separator membranes having excellent ionic conductivity besides the reduced gas crossover for highly efficient AWEs.…”

Section: Introductionmentioning

confidence: 99%

Zirconia Toughened Alumina-Based Separator Membrane for Advanced Alkaline Water Electrolyzer

et al. 2022

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Hydrogen is nowadays considered a favorable and attractive energy carrier fuel to replace other fuels that cause global warming problems. Water electrolysis has attracted the attention of researchers to produce green hydrogen mainly for the accumulation of renewable energy. Hydrogen can be safely used as a bridge to successfully connect the energy demand and supply divisions. An alkaline water electrolysis system owing to its low cost can efficiently use renewable energy sources on large scale. Normally organic/inorganic composite porous separator membranes have been employed as a membrane for alkaline water electrolyzers. However, the separator membranes exhibit high ionic resistance and low gas resistance values, resulting in lower efficiency and raised safety issues as well. Here, in this study, we report that zirconia toughened alumina (ZTA)–based separator membrane exhibits less ohmic resistance 0.15 Ω·cm2 and low hydrogen gas permeability 10.7 × 10−12 mol cm−1 s−1 bar−1 in 30 wt.% KOH solution, which outperforms the commercial, state-of-the-art Zirfon® PERL separator. The cell containing ZTA and advanced catalysts exhibit an excellent performance of 2.1 V at 2000 mA/cm2 at 30 wt.% KOH and 80 °C, which is comparable with PEM electrolysis. These improved results show that AWEs equipped with ZTA separators could be superior in performance to PEM electrolysis.

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Comparative analysis of performance of alkaline water electrolyzer by using porous separator and ion-solvating polybenzimidazole membrane

Cited by 10 publications

References 40 publications

Current and Potential Distribution in Two-Phase (Gas Evolving) Electrochemical Reactors by the Finite Volume Method

Current and Potential Distribution in Two-Phase (Gas Evolving) Electrochemical Reactors by the Finite Volume Method

Thin-Film Composite Membranes for Hydrogen Evolution with a Saline Catholyte Water Feed

Zirconia Toughened Alumina-Based Separator Membrane for Advanced Alkaline Water Electrolyzer

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