The lithium metal anode (LMA) is considered as a promising star for next-generation high-energy density batteries but is still hampered by the severe growth of uncontrollable lithium dendrites. To resolve the problem, a facile and efficient solution processed method with lithium nitride as a protective layer was demonstrated. The Li₃N-rich SEI successfully suppresses the penetration of Li dendrites, while the low electronic conductivity and the intrinsic electrochemical stability of Li₃N block side reactions between the electrolyte and Li. Here, we showed that the liquid electrolytes increase their cation transference number (from 0.37 to 0.66) when confined to a structurally rigid Li₃N host. This enabled stable interface between the lithium and electrolyte and Li dendrite suppression. As a result long stable plating/stripping cycling up-to 3500 hours at 0.5 mA cm^-2 was demonstrated along with a full cell cycling up-to 500 cycle at 1C rate.