When the current density increases, the NH3 current densities rise while the NH3 FEs remain constant at an average value of ∼27% as shown in Figure . The loss in FE could be attributed to excess Mg deposition, electrolyte breakdown, and corrosion. Figure demonstrates that the production rates of NH3 increase proportionally with rising current density. This suggests that the ratio of Mg protolysis to Mg3N2 protolysis rates is independent of potential, or perhaps both protolysis steps are barrierless at high potentials. Therefore, the potential-independent behavior could be due to a fixed fractional coverage of Mg3N2 on the cathode since protolysis is a thermochemical step. The coverage of Mg3N2 is balanced by nitridation and protolysis reactions, which are directly related to N2 pressure and proton donor, respectively.