Water increases Faradaic selectivity of Li-mediated nitrogen reduction.

The lithium-mediated system catalyses nitrogen to ammonia under ambient conditions. Herein we discover that trace amount of water - in contrast to prior reports from the literature – can effect a dramatic improvement in the Faradaic selectivity of N2 reduction to NH3. We report an optimal water concentration of 35.5 mM and LiClO4 salt concentration of 0.8 M allows a Faradaic efficiency up to 27.7% at ambient pressure. We attribute the increase in Faradaic efficiency to the incorporation of Li2O in the solid electrolyte interphase, as suggested by our X-ray photoelectron spectroscopy measurements. Our results highlight the extreme sensitivity of lithium mediated N2 reduction to small changes in the experimental conditions.