The so-called lithium redox-mediated nitrogen reduction reaction presents the only known process enabling genuine electrochemical conversion of N2 to ammonia. Notwithstanding the rapidly increasing investigative efforts, the commonly reported performances of the Li-mediated N2 electroreduction, viz. yield rate, current-to-ammonia (faradaic) efficiency and durability in operation, still pertain to the domain of academic research rather than practical development. Our most recent work focused on redesigning the key components of the electrolytic N2 reduction cell enabled breakthroughs in all the key metrics of the process. Specifically, we have introduced a stable proton shuttle based on the phosphonium cation that delivers protons to the cathode to form NH3 and is quantitatively reprotonated at the anode. The Li-mediated ammonia electrosynthesis from N2 and H2 with this proton carrier occurs at the highest reported to date faradaic efficiency (69 ± 1 %) and yield rate (53 ± 1 nmol s-1 cm-2) on a timescale of days. Even further improvements in the performance to achieve stable NH3 production rates of 150 ± 20 nmol s-1 cm-2 and close to 100% faradaic efficiency have very recently emerged through advances in the electrolyte and cathode design. These metrics are current best in the world and are approaching the industrially-set targets.
