Synergy of in-situ heterogeneous interphases tailored lithium deposition

The implementation of a robust artificial solid electrolyte interphase (ASEI) to replace the unstable natural SEI can regulate lithium deposition behaviors and avoid the safety hazards caused by dendrites permeation in lithium metal batteries. Despite of devoted efforts in tailoring components of ASEI, the intrinsic mechanism of interfacial synergy within the heterogeneous interphases has not been well elucidated yet. Herein, we show that the lithium plating/striping behaviors can be substantially enhanced (over 900 h with an overpotential of less than 20 mV at 1 mA·cm−2 in Li∣Li symmetric cells and 146 cycles in anode-free cells) by regulating the heterogeneous interphases. This favorable ASEI composed of LiF and Li3N components can be in-situ generated during cycling by large-scale fabricated fluorinated boron nitride coatings. Further, the synergy of each heterogeneous component within ASEI was explored theoretically and experimentally. Li3N has high adsorption energy and low ion diffusion barrier, which facilitates the transport of lithium ions and avoids its local accumulation to evolve into dendrites. Both the substrate and LiF are interfacially stable with high electron tunneling barriers, preventing the electrolyte decomposition and parasitic reactions. Finally, the high stiffness of the boron nitride also ensures lithium dendrites are suppressed once they grow, providing a stable environment for long-term cycling of lithium metal batteries.