Fig. 2: Performance of Li-mediated ammonia synthesis using phenol or lithium phenoxide as proton shuttles.

a The chronopotentiometry using phenol as proton shuttles (37 mM). b Faradaic efficiency changed with varying phenol concentrations. c The various phenol concentrations affect the distribution of produced ammonia in the electrolyte, gas phase, and electrode deposits. d The chronopotentiometry using lithium phenoxide as proton shuttles (37 mM). e Faradaic efficiency changed with varying lithium phenoxide concentrations. f The various lithium phenoxide concentrations affect the distribution of produced ammonia in the electrolyte, gas phase, and electrode deposits. All potentials are without iR correction. The potential cycling condition is −6 mA cm⁻² for 1 min and 0 mA cm⁻² for 1 min. All experiments passed a total charge of 700 C at the current density of −6 mA cm⁻² with the same potential cycling condition. Error bars represent the mean ± standard deviation derived from three independent measurements.