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Title: Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting

Abstract

Liquid/gas diffusion layers (LGDLs) play a crucial role in electrochemical energy technology and hydrogen production, and are expected to simultaneously transport electrons, heat, and reactants/products with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in proton exchange membrane fuel cells (PEMFCs), are unsuitable for PEM electrolyzer cells (PEMECs). In this study, a novel titanium thin LGDL with well-tunable pore morphologies was developed by employing nano-manufacturing and was applied in a standard PEMEC. The LGDL tests show significant performance improvements. The operating voltages required at a current density of 2.0 A/cm 2 were as low as 1.69 V, and its efficiency reached a report high of up to 88%. The new thin and flat LGDL with well-tunable straight pores has been demonstrated to remarkably reduce the ohmic, interfacial and transport losses. In addition, well-tunable features, including pore size, pore shape, pore distribution, and thus porosity and permeability, will be very valuable for developing PEMEC models and for validation of its simulations with optimal and repeatable performance. The LGDL thickness reduction from greater than 350 μm of conventional LGDLs to 25 μm will greatly decrease the weight and volume of PEMEC stacks, and representsmore » a new direction for future developments of low-cost PEMECs with high performance.« less

Authors:
 [1];  [2];  [2];  [2];  [2];  [1]
  1. Univ. of Tennessee Space Inst. (UTSI), Tullahoma, TN (United States)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Fuels, Engines and Emissions Research Center (FEERC); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). National Transportation Research Center (NTRC)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1261380
Grant/Contract Number:
AC05-00OR22725; FE0011585
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Energy
Additional Journal Information:
Journal Volume: 177; Journal ID: ISSN 0306-2619
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
08 HYDROGEN; proton exchange membrane fuel cells/ electrolyzer cells; liquid/gas diffusion layers; hydrogen production; water splitting; performance and efficiency

Citation Formats

Mo, Jingke, Retterer, Scott T., Cullen, David A., Toops, Todd J., Green, Jr, Johney Boyd, and Zhang, Feng-Yuan. Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting. United States: N. p., 2016. Web. doi:10.1016/j.apenergy.2016.05.154.
Mo, Jingke, Retterer, Scott T., Cullen, David A., Toops, Todd J., Green, Jr, Johney Boyd, & Zhang, Feng-Yuan. Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting. United States. doi:10.1016/j.apenergy.2016.05.154.
Mo, Jingke, Retterer, Scott T., Cullen, David A., Toops, Todd J., Green, Jr, Johney Boyd, and Zhang, Feng-Yuan. 2016. "Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting". United States. doi:10.1016/j.apenergy.2016.05.154. https://www.osti.gov/servlets/purl/1261380.
@article{osti_1261380,
title = {Thin liquid/gas diffusion layers for high-efficiency hydrogen production from water splitting},
author = {Mo, Jingke and Retterer, Scott T. and Cullen, David A. and Toops, Todd J. and Green, Jr, Johney Boyd and Zhang, Feng-Yuan},
abstractNote = {Liquid/gas diffusion layers (LGDLs) play a crucial role in electrochemical energy technology and hydrogen production, and are expected to simultaneously transport electrons, heat, and reactants/products with minimum voltage, current, thermal, interfacial, and fluidic losses. In addition, carbon materials, which are typically used in proton exchange membrane fuel cells (PEMFCs), are unsuitable for PEM electrolyzer cells (PEMECs). In this study, a novel titanium thin LGDL with well-tunable pore morphologies was developed by employing nano-manufacturing and was applied in a standard PEMEC. The LGDL tests show significant performance improvements. The operating voltages required at a current density of 2.0 A/cm2 were as low as 1.69 V, and its efficiency reached a report high of up to 88%. The new thin and flat LGDL with well-tunable straight pores has been demonstrated to remarkably reduce the ohmic, interfacial and transport losses. In addition, well-tunable features, including pore size, pore shape, pore distribution, and thus porosity and permeability, will be very valuable for developing PEMEC models and for validation of its simulations with optimal and repeatable performance. The LGDL thickness reduction from greater than 350 μm of conventional LGDLs to 25 μm will greatly decrease the weight and volume of PEMEC stacks, and represents a new direction for future developments of low-cost PEMECs with high performance.},
doi = {10.1016/j.apenergy.2016.05.154},
journal = {Applied Energy},
number = ,
volume = 177,
place = {United States},
year = 2016,
month = 6
}

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Cited by: 7works
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  • The electron beam melting (EBM) additive manufacturing technology was used to fabricate titanium liquid/gas diffusion media with high-corrosion resistances and well-controllable multifunctional parameters, including two-phase transport and excellent electric/thermal conductivities, has been first demonstrated. Their applications in proton exchange membrane eletrolyzer cells have been explored in-situ in a cell and characterized ex-situ with SEM and XRD. Compared with the conventional woven liquid/gas diffusion layers (LGDLs), much better performance with EBM fabricated LGDLs is obtained due to their significant reduction of ohmic loss. The EBM technology components exhibited several distinguished advantages in fabricating gas diffusion layer: well-controllable pore morphology and structure,more » rapid prototyping, fast manufacturing, highly customizing and economic. In addition, by taking advantage of additive manufacturing, it possible to fabricate complicated three-dimensional designs of virtually any shape from a digital model into one single solid object faster, cheaper and easier, especially for titanium. More importantly, this development will provide LGDLs with control of pore size, pore shape, pore distribution, and therefore porosity and permeability, which will be very valuable to develop modeling and to validate simulations of electrolyzers with optimal and repeatable performance. Further, it will lead to a manufacturing solution to greatly simplify the PEMEC/fuel cell components and to couple the LGDLs with other parts, since they can be easily integrated together with this advanced manufacturing process« less
  • In this study, a low-cost additive manufacturing technology, electron beam melting (EBM), is employed for the first time to fabricate titanium liquid/gas diffusion media with high-corrosion resistances and well-controlled multifunctional parameters, including two-phase transport and high electric/thermal conductivities. Its application in proton exchange membrane electrolyzer cells (PEMECs) has been investigated in-situ with modular galvano (MG) and galvano electrochemical impedance spectroscopy (GEIS) and characterized ex-situ with SEM and XRD. Compared with conventional woven and sintered liquid/gas diffusion layers (LGDLs), much better performance is obtained with EBM-fabricated LGDLs due to a significant reduction of ohmic losses. The EBM technology components exhibited severalmore » distinct advantages in fabricating LGDLs: well-controllable pore morphology and structure, rapid prototyping, fast manufacturing, highly customizable design, and economic. In addition, by taking advantage of additive manufacturing, it is possible to fabricate complicated three-dimensional designs of virtually any shape from a digital model into one single solid object faster, cheaper, and easier, especially for titanium components. More importantly, this development will provide LGDLs with well-controllable pore morphologies, which will be valuable to develop sophisticated models of PEMECs with optimal and repeatable performance. Finally and furthermore, it could lead to a manufacturing solution that greatly simplifies the PEMEC/fuel cell components.« less
  • Liquid/gas diffusion layers (LGDLs), which are located between the catalyst layer (CL) and bipolar plate (BP), play an important role in enhancing the performance of water splitting in proton exchange membrane electrolyzer cells (PEMECs). They are expected to transport electrons, heat, and reactants/products simultaneously with minimum voltage, current, thermal, interfacial, and fluidic losses. Here in this study, the thin titanium-based LGDLs with straight-through pores and well-defined pore morphologies are comprehensively investigated for the first time. The novel LGDL with a 400 μm pore size and 0.7 porosity achieved a best-ever performance of 1.66 V at 2 A cm -2 andmore » 80 °C, as compared to the published literature. The thin/well-tunable titanium based LGDLs remarkably reduce ohmic and activation losses, and it was found that porosity has a more significant impact on performance than pore size. In addition, an appropriate equivalent electrical circuit model has been established to quantify the effects of pore morphologies. The rapid electrochemical reaction phenomena at the center of the PEMEC are observed by coupling with high-speed and micro-scale visualization systems. Lastly, the observed reactions contribute reasonable and pioneering data that elucidate the effects of porosity and pore size on the PEMEC performance. This study can be a new guide for future research and development towards high-efficiency and low-cost hydrogen energy.« less