Long-term continuous ammonia electrosynthesis

Area of Science:

• Electrochemistry
• Materials Science
• Chemical Engineering

Background:

• Ammonia is vital for fertilizers and industry, and as a potential carbon-free fuel.
• Electrosynthesis of ammonia offers an alternative to the Haber-Bosch process, with lithium-mediated routes showing promise.
• Conventional solvents like tetrahydrofuran hinder continuous ammonia production due to polymerization and volatility.

Purpose of the Study:

• To develop a stable electrolyte for long-term, continuous ammonia electrosynthesis.
• To overcome the limitations of traditional solvents in ammonia production.
• To demonstrate a viable alternative to the Haber-Bosch process using electrosynthesis.

Main Methods:

• Investigated a chain-ether-based electrolyte for ammonia electrosynthesis.
• Utilized a flow electrolyser with a 25 cm² electrode.
• Operated the system at 1 bar pressure and room temperature for 300 hours.

Main Results:

• The chain-ether electrolyte demonstrated non-polymerization properties and a high boiling point.
• A stable solid-electrolyte interphase layer formed on the gas diffusion electrode.
• Achieved 300 hours of continuous operation with 64% ± 1% current-to-ammonia efficiency and 98% gas-phase ammonia purity.

Conclusions:

• Chain-ether electrolytes are crucial for stable, long-term continuous ammonia synthesis.
• This approach provides a promising, efficient, and stable method for ammonia production.
• The solvent plays a critical role in the performance and longevity of ammonia electrosynthesis systems.