To Carbon or Not to Carbon: Rethinking Electrode Design in Unitized Reversible Fuel Cells

The development of efficient and scalable energy storage systems remains a major challenge in the transition to renewable energy. Unitized reversible fuel cells (URFCs), capable of operating in both electrolysis and fuel cell modes, offer a promising solution. In this context, integrating the chlor-...

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Detalles Bibliográficos
Autores: Gomaa, Mahmoud Mohammed, Nopuo, Prince Sungdewie Adama, Rodrigo Rodrigo, Manuel Andrés, Lobato Bajo, Justo
Tipo de recurso: artículo
Fecha de publicación:2026
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:RUIdeRA. Repositorio Institucional de la UCLM
OAI Identifier:oai:ruidera.uclm.es:10578/47881
Acceso en línea:https://doi.org/10.1021/acsami.5c15144
https://pubs.acs.org/doi/full/10.1021/acsami.5c15144
https://hdl.handle.net/10578/47881
Access Level:acceso abierto
Palabra clave:carbon-based electrodes
chlor-alkali electrolysis
energy storage
microporous layer
system efficiency
unitized reversible fuel cell
Descripción
Sumario:The development of efficient and scalable energy storage systems remains a major challenge in the transition to renewable energy. Unitized reversible fuel cells (URFCs), capable of operating in both electrolysis and fuel cell modes, offer a promising solution. In this context, integrating the chlor-alkali process into URFCs enables not only cost-effective energy storage but also environmental benefits such as CO2 capture via alkaline absorption. While chlor-alkali electrolysis is well established, the reversible operation is not well known. This study addresses a key design question: the role of carbon-based materials in electrode architecture, specifically in the use of a carbon-based microporous layer. Titanium felt electrodes were modified with microporous layers (MPLs) containing 1, 2, and 3 mgC/cm2 and coated with a RuO2–Pt catalyst using a Pechini-type polymeric precursor method. The results showed that increasing the carbon content, the electrode resistance was reduced and surface hydrophobicity was enhanced, achieving the best results with 2 mgC/cm2 in the MPL. Moreover, in electrolysis mode, the hydrogen production efficiency improved with temperature, reaching 15 mgH2/Wh at 60 °C (surpassing industrial benchmarks). The system also achieved high Faradaic efficiency for hydrogen production (>98%) and enabled simultaneous CO2 capture via cathodic alkaline absorption. In fuel cell mode, the optimized electrode reached a peak power density of ~30 mW/cm2 at 60 °C, an order of magnitude higher than previously reported in the literature for similar systems. The results are very promising and position chlor-alkali-based reversible electrochemical cells as a promising platform for efficient, scalable, and multifunctional energy storage and conversion technologies.