Double interface regulation: Toward highly stable lithium metal anode with high utilization

The undesirable Li dendrite growth and other knock-on issues have significantly plagued the application of Li metal anodes (LMAs). Herein, we report that the synergistic regulation of double interfaces adjacent to the metallic Li anode can effectively prevent the dendritic Li growth, significantly improving the cycling performance of LMAs under harsh conditions including high current density and high depth of discharge. Thorough comparison of electrolytes demonstrated that 1 M lithium bis(fluorosulfonyl)imide (LiFSI) in 1,2-dimethoxyethane (DME) can yield a robust and lithiophobic LiF-rich upper interface (solid electrolyte interphase). Besides, the Sb-based buffer layer forms a lithiophilic lower interface on current collector. The synergy of the upper and lower interfacial engineering plays an important role for outstanding cyclability of LMAs. Consequently, the plating/stripping of Li can be stably repeated for 835 and 329 cycles with an average Coulombic efficiency (CE) above 99% at 1 and 3 mA h cm(-2), respectively. Surprisingly, the Li||Li symmetric cell can even withstand the baptism of current density up to 20 mA cm(-2). The excellent performance validates that the facile synergistic regulating of interfaces adjacent to the metallic Li anode provides an effective pathway to stabilize LMAs.

Automated summary

Regulating the double interfaces adjacent to the metallic Li anode effectively prevents dendritic Li growth, significantly improving the cycling performance of LMAs. The synergy between the LiF-rich upper interface formed by 1M LiFSI in DME and the lithiophilic lower interface on the current collector plays a key role in enhancing the cyclability of LMAs. This approach allows stable plating/stripping cycles with high Coulombic efficiency and withstands high current densities, demonstrating an effective pathway to stabilize LMAs.