Enhancing Ammonia Production by Ag Incorporation in Li-Mediated Nitrogen Reduction Reactions

Abstract

Conventional ammonia production relies on the Haber-Bosch process, which is an energy-intensive process and emits significant amounts of CO2. Recent advances in electrochemical Li-mediated nitrogen reduction reactions (Li-NRRs) provide sustainable pathways. While efforts have been made to develop electrolytes and devices, research on cathode materials for Li-NRRs is still limited. This study demonstrates that the introduction of Ag into the copper cathode system significantly contributes to the ammonia production activity of Li-NRRs, and improved performance is obtained especially for various Li salts containing fluorine in electrolytes. Small amounts of Ag salts enhance the selectivity toward ammonia, forming LiF and Ag-Li alloys in the solid electrolyte interphase. We demonstrate that lithiophilic Ag effectively mediates Li cycling, decreasing the overpotentials required for Li plating during Li-NRRs. Our insights provide perspectives on the development of electrode materials and the potential to utilize unexplored metals as electrodes for Li-NRRs. © 2024 American Chemical Society