Less is more : a comprehensive study on the effects of the unmber of gas diffusion layers on air-cathode microbial fuel cells
Sánchez-Peña, Pilar (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Rodriguez, Jesús (Centro Nacional de Hidrógeno (Puertollano, Espanya))
Montes Martínez, Raquel (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Baeza Labat, Juan Antonio (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Gabriel, David (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Baeza Labat, Maria del Mar (Universitat Autònoma de Barcelona. Departament de Química)
Guisasola, Albert (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)

Date:	2021
Description:	11 pàg.
Abstract:	Air-cathode microbial fuel cells (AC-MFC) use a gas-diffusion-layer (GDL) coating based on polytetrafluoroethylene applied to the cathode to prevent electrolyte leakage. However, this type of GDL can also lead to a decrease in MFC performance due to electron-transfer limitation, mass-transfer limitation or catalyst availability. This study provides a comprehensive understanding of the significance of the GDL coating, demonstrating the interaction between the number of GDL coatings and the external resistance (Rext) used. An experimental design in 28 mL AC-MFCs was prepared and conducted using two different Rext (10 and 249 Ω) and four different GDL coatings (1 to 4 layers). The coating effect was not significant when operating with a high Rext, where the electron transfer was the limiting process. However, when the Rext was low, the amount of polytetrafluoroethylene limited the cathode performance due to a significant decrease in the Pt availability on the catalytic surface. Thus, GDL-1 with 10 Ω as Rext reached 0. 96 mA/cm2, 3-fold higher than that obtained with 249 Ω as Rext (ca. 0. 30 mA/cm2). Besides, the current density did not vary noticeably in the other cathodes with 249 Ω as Rext. Contrarily, the current density with 10 Ω as Rext decreased as the number of GDL increased (0. 74, 0. 57 and 0. 37 for GDL-2, GDL-3 and GDL-4 respectively). These values agreed with those of the polarization curve. Furthermore, limitations were also observed in electrochemical impedance spectroscopy measurements: the charge resistance increased with the number of GDL, related to the ease of electron flow. These values were18 Ω, 22 Ω, 53 Ω and 58 Ω for GDL-1, GDL-2, GDL-3 and GDL-4, respectively, for both 10 and 249 Ω cathodes.
Grants:	Ministerio de Economía y Competitividad CTQ2017-82404-R Agència de Gestió d'Ajuts Universitaris i de Recerca 2018/FI_B01161 Agència de Gestió d'Ajuts Universitaris i de Recerca 2017/SGR-1175
Note:	Altres ajuts: acords transformatius de la UAB
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Air-cathode ; External resistance ; Gas diffusion layer ; Microbial fuel cells ; Thickness ; Microbial fuel cell
Published in:	ChemElectroChem, Vol. 8, issue 17 (Sep. 2021) , p. 3416-3426, ISSN 2196-0216

DOI: 10.1002/celc.202100908

11 p, 6.1 MB

Supporting information 5 p, 696.9 KB

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