Artificial Li3N SEI-Enforced Stable Cycling of Li Powder Composite Anode in Carbonate Electrolytes

Abstract

Lithium metal is considered one of the most attractive anode materials for next-generation batteries. However, the practical application of rechargeable Li-metal batteries has been hindered by the uncontrollable growth of Li dendrites and large volume changes during electrochemical cycling, leading to low Coulombic efficiency and safety concerns. This study reports a facile process of printing copper nitride nanowires (Cu3N NWs) onto Li metal powder (LMP) composite anode surface via a roll-pressing technique. Cu3N readily reacts with Li to form lithium nitride (Li3N), which is regarded as an excellent component for the interfacial layer on Li metal. The Li3N layer possesses a high ionic conductivity and ensures a homogeneous Li-ion flux, resulting in the suppression of dendrites. As a result, Li/Li symmetric cells assembled with the Li3N-LMP electrode exhibited lower overpotentials and superior cycling performance. Furthermore, NCM622/Li3N-LMP full cells demonstrated better capacity retention behavior (over 90% after 250 cycles) and higher discharge capacities during rate capability tests compared to the bare LMP cell. This study highlights the importance of a rational design of interfacial layers on LMP anodes for stable and long-term cycling.