Sustainable ammonia synthesis: Just around the corner?

Li-mediated electrochemical synthesis of ammonia has been put forward as a possible alternative to the Haber-Bosch process, which is harmful to the environment and requires centralized operation. However, it has historically been plagued by low Faradaic efficiency, rate, and current density. In this issue of Joule, Chorkendorff and co-workers present a version of the process that meets certain industrial benchmarks and unveil new insights into the reaction kinetics along the way. Their observations are borne out by a recent study in Nature from MacFarlane and co-workers which also demonstrates extremely high Faradaic efficiency and high rates toward ammonia synthesis. Li-mediated electrochemical synthesis of ammonia has been put forward as a possible alternative to the Haber-Bosch process, which is harmful to the environment and requires centralized operation. However, it has historically been plagued by low Faradaic efficiency, rate, and current density. In this issue of Joule, Chorkendorff and co-workers present a version of the process that meets certain industrial benchmarks and unveil new insights into the reaction kinetics along the way. Their observations are borne out by a recent study in Nature from MacFarlane and co-workers which also demonstrates extremely high Faradaic efficiency and high rates toward ammonia synthesis. Electrosynthesis of ammonia with high selectivity and high rates via engineering of the solid-electrolyte interphaseLi et al.JouleAugust 22, 2022In BriefAchieving high selectivity at a commercially relevant current density holds the key to the practical applications of electrochemical NH3 synthesis. Here, a record selectivity and NH3 production rate at a current density of −1.0 A cmgeo−2 under 20 bar N2 are achieved through a combination of highly porous Cu electrode and LiBF4-based electrolyte. Theoretical calculations and experimental analysis suggest that a compact and uniform LiF-enriched SEI layer facilitates even lithium plating and suppresses the undesired electrolyte decomposition. Full-Text PDF Open Access