Lithium-Germanium Alloy Interfaces for Efficient Low-Pressure Ammonia Synthesis

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Chemistry

Background:

• The Haber-Bosch process for ammonia synthesis is energy-intensive.
• Electrochemical nitrogen reduction reaction (NRR) offers a sustainable alternative.
• Previous NRR studies focused on solution-phase optimization.

Purpose of the Study:

• To develop a novel electrode engineering strategy for efficient electrochemical nitrogen fixation.
• To investigate the performance of triethylammonium germanate-modified copper (Cu/TEG) electrodes for lithium-mediated NRR.
• To understand the role of interfacial engineering in enhancing NRR.

Main Methods:

• Electrode fabrication using triethylammonium germanate-modified copper.
• Multi-technique material characterization.
• Electrochemical measurements and Density Functional Theory (DFT) calculations.

Main Results:

• Formation of a Li₁₅Ge₄ alloy on the electrode surface during Li-NRR.
• The Li₁₅Ge₄ alloy facilitates lithium deposition and enhances N₂ adsorption.
• Achieved a Faradaic efficiency of 92.5% at 4 bar N₂ pressure.
• Reached a pseudo-energy efficiency of 17.6%, the highest reported for a batch cell.

Conclusions:

• Dual-function interfacial engineering via lithium-germanium alloy formation is a breakthrough strategy for NRR.
• This approach moves beyond solution-phase optimization for efficient electrochemical nitrogen fixation.
• The developed Cu/TEG electrodes represent a significant advancement in sustainable ammonia synthesis.