The Low Temperature Fuel Cells group works on electrochemical energy conversion in polymer electrolyte fuel cells (PEMFC). It is composed of two PhD researchers, and a variable number of students and visitors.

Activities comprise fundamental research on materials and electrode processes, fabrication of components of fuel cells, fuel cell assembly and testing, and developments of applications with fuel cells. A brief explanation is given below.

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Studies are carried out of electrochemical reactions involved in energy conversion within a fuel cell. The most limiting reaction for the efficiency of a low temperature fuel cell is the oxygen reduction. This reaction is studied under controlled mass transfer conditions with the help of a rotating disk electrode (rde). Studies have been conducted with rde on disks and supported particles, including platinum nanoparticles supported on carbon black (Pt/C) and particles prepared by electrodeposition on glassy carbon (Pt, PtCo and Pt-WO₃). An analytical model is proposed for the current at an rde under surface diffusion limitation.  

An analytical model is proposed for the current at an rde under surface diffusion limitation. 

Degradation conditions of electrode materials in fuel cell are analysed, as well as fundamental studies of reactions yielding to electrodes corrosion with the help of techniques like impedance spectroscopy and membrane inlet mass spectrometry.

References

Degradation Study by Start-Up/Shut-Down Cycling of Superhydrophobic Electrosprayed Catalyst Layers Using a Localized Reference Electrode Technique, Paloma Ferreira-Aparicio, Antonio M. Chaparro, M. Antonia Folgado, Julio J. Conde, Edward Brightman, Gareth Hinds, ACS Appl. Mater. Interfaces, Vol. 9 (2017) 10626−10636. DOI: 10.1021/acsami.6b15581

- Current at a Rotating Disk Electrode under Electrosorption and Surface Diffusion Limitation, Antonio M. Chaparro. Journal of The Electrochemical Society, 164 (11) E3522-E3530 (2017). DOI: 10.1149/2.0491711jes

Influence of the cathode catalyst layer thickness on the behaviour of an air breathing PEM fuel cell, Paloma Ferreira-Aparicio, Antonio M. Chaparro, Advances in Energy Research, Vol. 2, No. 2 (2014) 73-84.

Analysis of the Steady State and Transient Currents for a Rotating Disk Electrode under Surface Diffusion Limitation, Antonio M. Chaparro, Journal of The Electrochemical Society, 161 (8) E3078-E3085 (2014).

Physico-chemical study of the degradation of membrane-electrode assemblies in a proton exchange membrane fuel cell stack. P. Ferreira-Aparicio, B.Gallardo-López, A.M.Chaparro, L.Daza, J. Power Sources 196 (2011) 4242-4250.

Study of spillover effects with the rotating disk electrode. A.M. Chaparro, Electrochim. Acta 58 (2011) 691-698.

Anode degradation effects in PEMFC stacks by localized fuel starvation. P. Ferreira-Aparicio, A.M. Chaparro, B. Gallardo, M.A. Folgado, L. Daza, ECS Transactions 26 (1) (2010) 257-265.

Microstructure of electrospray deposited catalyst layers for PEMFC electrodes. A.M.Chaparro, M.A.Folgado, P.Ferreira-Aparicio, B.Gallardo, A.J.Martín, L.Daza, ECS Transactions 26 (1) (2010) 197-205.

Theoretical analysis of the limiting diffusion current at a particulate rotating disk electrode. A.M. Chaparro, A.J. Martín, L. Daza, ECS Transactions 25 (23) (2010) 125-133.

New Insights into Proton Surface Mobility Processes in PEMFC Catalysts Using Isotopic Exchange Methods. P. Ferreira-Aparicio, Appl. Mater. Interfaces 1 (9) (2009) 1946-1957.

High surface area graphite as alternative support for proton exchange membrane fuel cell catalysts. P. Ferreira-Aparicio, M.A. Folgado, L. Daza, J. Power Sources 192 (2009) 57-62.

PEMFC catalyst synthesis and characterization: relevance of structural and chemical factors on surface diffusion processes. P. Ferreira Aparicio, Electrochem. Solid State Lett. 12 (3) (2009) B38-B42.

Rotating disk electrode analysis of oxygen reduction at platinum particles under limiting diffusion conditions. A.J. Martín, A.M. Chaparro, M.A. Folgado, J. Rubio, L. Daza, Electrochim. Acta 54 (2009) 2209-2217.

Enhanced rate of surface diffusion processes in highly dispersed PEMFC catalysts on surface functionalized carbons: its relationship with the catalyst structure. P. Ferreira-Aparicio, ECS Transactions 13 (28) (2008) 41-55.

Evaluation of adsorption properties of platinum catalysts for proton exchange membrane fuel cells: establishing criteria for the standardization of active area measurements. P. Ferreira-Aparicio, Chem. Mater. 19 (2007) 6030-6040.

Study of electrochemical instabilities of PEMFC electrodes in aqueous solution by means of membrane inlet mass spectrometry. A.M. Chaparro, N. Mueller, C. Atienza, L. Daza, J. Electroanal. Chem. 591 (2006) 69-73.

Electrochemical characterisation of Pt/C suspensions for the reduction of oxygen. R. Benítez, A.M. Chaparro, L. Daza, J. Power Sources 151 (2005) 2-10.
 

The group works since more than 15 years ago in an alternative technique for the fabrication of electrodes for low temperature PEMFC, like the electrospray deposition. Electrospray allows preparing high quality and reproducible electrodes, with enhanced properties, like low platinum content, high activity, and high durability. Results have been contrasted in numerous articles and collaborations with other laboratories (Spain, Switzerland, UK, USA). Electrospray is based on the deposition of suspensions of the catalyst and an ionomer (Nafion) under the influence of a strong electric field. Electrostatic interactions among catalyst particles and ionomer chains, and with the substrate, yield a particular meso-macro porous morphology of the catalyst layers with larger electrochemical surface area and stronger interaction of catalyst and ionomer. The electrosprayed layers show superhydrophobic character, that provides good transport properties for the liquid water generated inside the cell. As a consequence, the electrosprayed catalyst layers show higher active surface area and improved mass transport conditions, which gives rise to 20-25% enhancement in the maximum power conversion efficiency, compared with commercial electrodes under standard operating conditions. Electrospray deposition can be carried out on membrane and on the GDL.

A new application of the electrosprayed deposition is the preparation of superhydrophobic carbon layers for the protection of metallic surfaces against corrosion. Published results show that films with 0.4 mg·cm-2 carbon give rise to complete and stable protection in acidic solution.

Among new materials development for fuel cell application, the group has started the exploration of graphene as a material for protecting metallic surfaces of the cell (contacts) against corrosion.

The electrodeposition of catalyst particles on gas diffusion substrates is another technique developed for the preparation of electrodes for PEMFC. Electrodes have been prepared with different catalyst compositions, like Pt, PtCo, and Pt-WO₃. The electrodeposition reactions are studied by means of the electrochemical quartz crystal microbalance (EQCM), and then, optimized conditions are determined for electrode fabrication on gas diffusion substrate, normally carbon cloths and carbon papers covered with microporous carbon layers. A national patent has been approved for the electrodeposition cell and the process.

In addition, the group has at disposition the standard air brushing technique for the preparation of electrodes, either on membrane or on GDL.

References

Anti-corrosion coating for metal surfaces based on superhydrophobic electrosprayed carbon layers, Julio J. Conde, Paloma Ferreira-Aparicio, Antonio M. chaparro, Applied Materials Today 13 (2018) 100-106. DOI: 10.1016/j.apmt.2018.08.001

Understanding the Behavior of Electrosprayed Carbon Black-Nafion Composite Layers, J. J. Conde, A.M. Chaparro, P. Ferreira-Aparicio, Fuel Cells  18 (5) (2018) 627-639. DOI: 10.1002/fuce.201700218

Degradation Study by Start-Up/Shut-Down Cycling of Superhydrophobic Electrosprayed Catalyst Layers Using a Localized Reference Electrode Technique. Paloma Ferreira-Aparicio, Antonio M. Chaparro, M. Antonia Folgado, Julio J. Conde, Edward Brightman, and Gareth Hinds. ACS Appl. Mater. Interfaces 9 (12) (2017) 10626–10636. DOI: 10.1021/acsami.6b15581

Study of superhydrophobic electrosprayed catalyst layers using a localized reference electrode technique. A.M. Chaparro , P. Ferreira-Aparicio , M.A. Folgado , E. Brightman , G. Hinds. J. Power Sources 325 (2016) 609-619. DOI: 10.1016/j.jpowsour.2016.06.077.

Catalyst layers for proton exchange membrane fuel cells prepared by electrospray deposition on Nafion membrane. A.M. Chaparro, P. Ferreira-Aparicio, M.A. Folgado, A.J. Martín, L. Daza, J. Power Sources 196 (2011) 4200-4208.

Properties of catalyst layers for PEMFC electrodes prepared by electrospray deposition. A.M. Chaparro, M. A. Folgado, P. Ferreira-Aparicio, A.J. Martín, I. Alonso-Álvarez,  L. Daza, J. Electrochem. Soc. 157 (7) (2010) B993-B999.

EQCM study of the electrodeposition of Pt-WO₃ and its catalytic activity towards the ORR. A.J. Martín, A.M. Chaparro, L.Daza, ECS Transactions 33 (1) (2010) 309-320.

Pt-Co electrodeposited electrodes: surface distribution and depth profile. A.J. Martín, A.M. Chaparro, C. Guillén, M.A. Folgado, L. Daza, ECS Transactions 25 (1) (2009) 2039-2047.

PEMFC electrode preparation by electrospray: Optimization of catalyst load and ionomer content. A.M. Chaparro, B. Gallardo, M.A. Folgado, A.J. Martín, L. Daza, Catal. Today 143 (2009) 237-241.

Técnicas avanzadas para la disminución del platino en pilas de combustible de membrana polimérica (PEMFC). I. Cendoya, O. Miguel, P. Ferreira Aparicio, Energética, Julio/Agosto 2008.

Electrodeposition of Platinum on Carbon Black for Fuel Cell Application. A.J. Martín, A. M. Chaparro, M. A. Folgado, B. Gallardo, L. Daza, ECS Transactions 13 (10) (2008) 13-18.

Electrochemical quartz crystal microbalance study of the electrodeposition of Co, Pt and Pt-Co alloy. A.J. Martín, A.M. Chaparro, L. Daza, J. Power Sources 169 (2007) 65-70.

PEMFC electrode preparation: Influence of the solvent composition and evaporation rate on the catalytic layer microstructure. R. Fernández, P. Ferreira-Aparicio, L. Daza, J. Power Sources 151 (2005) 18-24.
 

Electrodes and other cell components, like plates, contacts or gaskets, are fabricated and mounted in single cells for testing under normalized conditions.

The group has one test bench for single cell operation (15 cm² active area) under controlled gas flow rates, compositions, humidification and back pressure. Studies are carried out of cell performance (IV curves), electroactive area determination (H_UPD and CO methods), cell impedance, and long term durability.

Another test bench has been mounted for the operation of portable fuel cells, with a climatic chamber for testing under ambient temperature and humidity control. The bench has possibilities for operation of 8 cells in parallel.

Standard protocols are applied according to the international standard developed by International Electrotechnical Commission  (IEC/TC105). The group has an active participation in the development of standards for single cell testing, and presides at present the national standardization committee (CTN 206/SC105).

References

Thermal neutron radiography of a passive proton exchange membrane fuel cell for portable hydrogen energy systems. Antonio M. Chaparro, P. Ferreira-Aparicio, M. Antonia Folgado, Rico Hübscher, Carsten Lange, Norbert Weber. Journal of Power Sources. Volume 480, 228668, 2020. https://doi.org/10.1016/j.jpowsour.2020.228668.

Single Cell Study of Water Transport in PEMFCs with Electrosprayed Catalyst Layers, M. A. Folgado, J. J. Conde, P. Ferreira-Aparicio, A.M. Chaparro, Fuel Cells  18 (5) (2018) 602-612. DOI: 10.1002/fuce.201700217

An optical and single cell study of the assembly of a PEMFC with dry and expanded Nafion, M.A. Folgado, P. Ferreira-Aparicio, A.M. Chaparro, Int. J. Hydrogen Energy 41 (2016) 505-515. DOI: 10.1016/j.ijhydene.2015.10.120

Study of the Constrained Expansion of Nafion within the Hardware of a PEMFC, M.A. Folgado, P. Ferreira-Aparicio, A.M. Chaparro, Electrochemical Society Transactions, 64 (3) 729-738 (2014).

Influence of the gas diffusion cathode structure on the performance of an air-breathing proton exchange membrane fuel cell. P. Ferreira-Aparicio, A.M. Chaparro, Int. J. Hydrogen Energy 39 (2014) 3997-4004.

Single cell study of electrodeposited cathodic electrodes based on Pt-WO₃ for polymer electrolyte fuel cells. A.J. Martin, A.M. Chaparro, L. Daza,  J. Power Sources 196 (2011) 4187-4192.

Testing of catalyst coated membranes for PEMFC, prepared by electrospray deposition. A. M. Chaparro, I. Alonso-Álvarez, P. Ferreira-Aparicio, M. A. Folgado, A. J. Martín, L. Daza, ECS Transactions 33 (1) (2010) 267-273.

Characterization and single cell testing of Pt/C electrodes prepared by electrodeposition. A.J. Martín, A.M. Chaparro, B. Gallardo, M.A. Folgado, L. Daza,  J. Power Sources 192 (2009) 14-20.

Comparative analysis of the electroactive area of Pt/C PEMFC electrodes in liquid and solid polymer contact by underpotential hydrogen adsorption/desorption. A.M. Chaparro, A.J. Martín, M.A. Folgado, B. Gallardo, L. Daza, Int. J. Hydrogen Energy 34 (2009) 4838-4846.

Study of membrane electrode assemblies for PEMFC, with cathodes prepared by the electrospray method. A.M. Chaparro, R. Benítez, L. Gubler, G.G. Scherer, L. Daza, J. Power Sources 169 (2007) 77-84.

Single cells and small stacks are being designed for applications powered by hydrogen and fuel cells. Cell of 'air breathing' type have been fabricated and tested in small portable applications, demonstrating up to 20W·h autonomy with 1g H₂ stored in the application. The cells are able to work with ambient air inlet in the cathode (‘air breathing’) that allows for maximizing compactness and miniaturization.

Tools are available for design and fabrication of small components (plates, gaskets, contacts). A patent of fuel cell model has been prepared, including the development of a new anode type able to work under fully dead end conditions, optimal for 100% hydrogen utilization with subsidiary system requirements.

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References

Novel Dead-Ended Anode Design For Self-Regulating Humidification In An Air-Breathing H2-PEM Fuel Cell, P. Ferreira-Aparicio, A.M. Chaparro, Electrochemical Society Transactions, 64 (3) 945-950 (2014).

Influence of the cathode architecture in the frequency response of self-breathing proton exchange membrane fuel cells, P. Ferreira-Aparicio, A.M. Chaparro, Journal of Power Sources 272 (2014) 79-89.

A portable system powered with hydrogen and one single air-breathing PEM fuel cell. J. Fernández-Moreno, G. Guelbenzu, A.J. Martín, M.A. Folgado, P. Ferreira-Aparicio, A.M. Chaparro, Appl. Energy 109 (2013) 60-66.

Data results and operational experience with a solar hydrogen system. A.M. Chaparro, J. Soler, M.J. Escudero, E.M.L. de Ceballos, U. Wittstadt, L. Daza,  J. Power Sources 144 (2005) 165-169.

Testing an isolated system powered by solar energy and PEM fuel cell with hydrogen generation. A.M. Chaparro, J. Soler, M.J. Escudero, L. Daza,  Fuel Cells Bulletin, Nov. 2003. 

http://projects.ciemat.es/web/elige

http://projects.ciemat.es/web/elhyport/

The group has established collaborations with other groups, like:

• Helmholtz-Zentrum Dresden-Rossendorf, Institut für Fluiddynamik (Germany), Norbert Weber
• Lawrence Berkeley National Laboratory (USA), Adam Weber
• National Physical Laboratory (Londres, UK), Garet Hinds
• Univ. Castilla-La Mancha (Spain), Justo Lobato
• Paul Scherrer Institut (Switzerland), G. G. Scherer
• CINVESTAV (México), O. Solorza-Feria
• Univ. Daido (Japan), M. Hori

There are also collaborations with industry:

• Schunk Ibérica
• Hidrogena
• Aramis (Spain)

Books

Portable Hydrogen Energy Systems. Fuel Cells and Storage Fundamentals and Applications

Edited by Paloma Ferreira-Aparicio and Antonio M. Chaparro.

Academic Press, 2019. DOI: 10.1016/C2016-0-04605-3

Patents

• "Método de preparación de electrodos para la preparación de pilas de combustibles poliméricas". Publication number: ES2396664.
• "Pila de combustible de baja temperatura para aplicaciones portátiles que funciona con hidrógeno y aire ambiente".
• Publication number: ES2466590.

Other activities

• International Electrotechnical Commission (IEC) IEC/TC105 group for Fuel Cells Normalization.
• President of the national normalization committee for fuel cells CTN206/SC105.
• Memberships: International Electrochemical Society (IEC), Electrochemical Society (ECS), Spanish Fuel Cells Association (APPICE).