D.J. Li, Y.J. Sun, M.H. Li, X.L. Cheng, Y. Yao, F.Y. Huang, S.H. Jiao, M. Gu, X.H. Rui, Z. Ali, C. Ma, * Z.-S. Wu, * and Y. Yu *

ACS Nano, 2022, 16.

DOI: 10.1021/acsnano.2c07049 [PDF]

Thepractical application ofNa/K-metallicanode is intrinsically hindered by the poor cycle life and safety issues owing to theunstable electrode/electrolyte interfaceand uncontrolled dendrite growth during cycling. Herein, we solve these issues throughin-situreaction of oxyhalogenide (BiOCl) and Nato construct a new-concept artificial solid electrolyte interphase (SEI) layer consisting of alloy(Na₃Bi)andsolid electrolyte(Na₃OCl) on the surface of Na anode.As demonstrated by theoretical and experimental results,such artificial SEI layer combinesthe synergistic properties of high ionic conductivity, electronic insulation, and interfacial stability, leading to uniform dendrite-free Na deposition beneath thehybrid SEI layer.The protected Na anode presents a low voltage polarization of 30 mV, achieving extended cycling life of 700 h at 1 mA cm^-2incarbonate-based electrolyte. The full cell based on theNa₃V₂(PO₄)₃cathodeand hybrid SEI-protected Na anode shows long-term stability. When this strategy is applied to K metal anode, the protected K anode also reaches over 4000 h at 0.5 mA cm^-2with a low voltage polarization of 100 mV.Our work provides an important insight into the design principles of the stable artificial SEI layer forhigh-energy-density metal batteries.