Cerium Oxide-Polysulfone Composite Separator for an Advanced Alkaline Electrolyzer

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Renewable energy sources present grid stability challenges due to their intermittent nature.
• Power-to-gas technology, utilizing electrolyzers, is crucial for large-scale energy storage and managing electricity fluctuations.
• Current organic/inorganic composite separators in electrolyzers suffer from high ohmic resistance and gas crossover, limiting efficiency.

Purpose of the Study:

• To develop and evaluate a novel cerium oxide (ceria) nanoparticle and polysulfone composite separator for electrolyzers.
• To assess the performance of this new separator against commercial alternatives in terms of resistance and gas permeability.
• To investigate the impact of separator properties on electrolyzer efficiency and operational stability.

Main Methods:

• Fabrication of a ceria nanoparticle/polysulfone composite separator with controlled pore size and wettability.
• Characterization of the separator's area resistance and hydrogen permeability in 30 wt% potassium hydroxide (KOH) electrolyte.
• Performance testing of an electrolyzer cell utilizing the novel separator and advanced catalysts at 800 mA cm⁻² and 80 °C.

Main Results:

• The ceria nanoparticle/polysulfone separator achieved a low area resistance of 0.16 Ω cm² and hydrogen permeability of 1.2 × 10⁻¹² mol cm⁻¹ s⁻¹ bar⁻¹.
• The developed separator outperformed the commercial Zirfon PERL separator.
• An electrolyzer cell with the 100 nm ceria nanoparticle/polysulfone separator demonstrated high performance (1.84 V at 800 mA cm⁻²).
• Reduced average pore size (77 nm) and enhanced wettability (contact angle 75°) contributed to improved performance.

Conclusions:

• Ceria nanoparticle-based composite separators offer superior performance compared to commercial zirconia-based separators for electrolyzer applications.
• The novel separator design effectively reduces ohmic resistance and gas crossover, enhancing overall electrolyzer efficiency.
• This advancement supports the development of more effective energy storage solutions for renewable energy integration.