Optimizing energy consumption considering interfacial pH changes using an asymmetric electrode design: The case of alkaline electrolysis

Autor(es)

Wosiak, Gabriel ; Staciaki, Felipe ; Von Stein, Raphaella ; Pereira, Ernesto

• Tipo de documento: Artigo Científico
• Fonte: INTERNATIONAL JOURNAL OF HYDROGEN ENERGY; v. 106, p. 8-pg., 2025-03-06.

Resumo

Electrochemical reactions conducted in aqueous electrolytes are normally accompanied by consumption or production of H+/OH- ions, which can lead to significant interfacial pH (pHi) changes near the electrode surface. In electrochemistry the pHi change occurs in various processes and plays a role impact in reactions increasing the energy consumption and, consequently, negatively affecting the process efficiency. In this paper, we present a simple and scalable method to mitigate the pHi changes by using a cell design with electrode asymmetry increasing the anode area relative to the cathode area, thereby reducing energy consumption. This configuration has been tested in alkaline wa-ter electrolysis using a multivariate approach in both laboratory and industrial current density conditions, and the results were supported by numerical simulations. The results indicated that an increase in the ratio between electrode areas reduces the cell potential and energy consumption, improving the energy efficiency (11.6%). The simulations demonstrated that when the area quotient (AQ) is 30, the interfacial pH changes is 397.4 times slower compared to an AQ = 1. Finally, under high current conditions, the asym-metric electrode configuration significantly reduces the cell potential leading to 17.1% of saved energy at jcat = 200 mA cm- 2. These results indicate that the method can be scaled and applied in various settings, offering a promising solution to the challenge of mitigating the interfacial pH changes and improving energy efficiency and performance in electrochemical processes, especially industrial applications. (AU)

• Processo FAPESP: 21/11630-1 - Desenvolvimento de novos materiais e métodos para dessalinização capacitiva
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