Advancing Li-Mediated Electrochemical Ammonia Synthesis: Tackling Challenges for a Sustainable Future

Abstract

Electrochemical ammonia synthesis is emerging as a promising alternative to the traditional Haber-Bosch process, which has long been criticized for its high energy consumption and significant CO2 emissions.[1] The electrochemical approach offers several advantages, including milder operating conditions, reduced carbon footprint, and the potential for decentralized production using renewable energy sources. Our current focus lies on better understanding nitrogen reduction mechanisms and optimizing electrolyte systems to enhance ammonia yield rates and Faradaic efficiency (FE) in ambient conditions, following the work of Simonov et al[2] who achieved almost 100% FE on the electrochemical nitrogen reduction reaction under 15 bar of nitrogen gas and at room temperature. Key challenges include the electrolyte solvent selection, where the choice of solvent significantly impacts reaction selectivity and long-term operation; electrode materials, as different counter electrodes (e.g., Ni vs. Pt) affect reaction efficiency and stability; the Solid Electrolyte Interphase (SEI) layer, which plays a crucial role in reaction dynamics by acting as both a protective shield and a potential barrier; and bias application, where continuous versus pulsed bias affects lithium electrodeposition and overall reaction dynamics.[3] Our latest study includes using DMI as an electrolyte solvent to reduce electrode surface degradation, exploring pulsed bias techniques to overcome limitations of continuous gating, and investigating the SEI layer's impact on reactant permeability and catalytic properties.[4] While electrochemical ammonia synthesis shows great promise, scaling up to match industrial production rates remains a significant challenge. Ongoing research aims to address these issues through reactor engineering, real-time reaction monitoring, and identification of key catalytic variables. As efforts continue to overcome hurdles in electrochemical ammonia synthesis, this technology has the potential to revolutionize not only agriculture and chemical industries but also the energy sector by enabling sustainable, decentralized ammonia production using renewable energy sources.