Insight into bulk charge transfer of lithium metal anodes by synergism of nickel seeding and LiF-Li3N-Li2S co-doped interphase

Cycling lithium (Li) metal anode with a low negative/positive capacity (N/P) ratio is critical to build high-energy-density Li metal batteries (LMBs). Many strategies focusing on interfacial protection are limited to shallow conditions using excessive Li with a high negative/positive capacity (N/P) ratio > 50. Herein, we demonstrate a deeply enhanced charge transfer kinetic by a rational incorporation of nickel (Ni) seeds in the Li anodes with a tailored interfacial chemistry. The Ni seeds in the bulk Li anode not only act as well-dispersed nucleation sites to enable Ni-seeded growth of granular Li deposits, but also adsorb acetonitrile (AN) molecules when the Ni-seeded Li anodes are paired with an AN-based electrolyte using lithium bis-(fluorosulfonyl)imide as salt, forming a fast Li+ conducing interphase with co-produced LiF, Li3N and Li2S components. These benefits conduct an exchange current density similar to 20 times higher than that of the bare Li in conventional carbonate electrolytes. Stable cycling of LMBs with a practical cathode loading (similar to 5 mAh cm(-2)) and a low N/P capacity ratio of 2 is also demonstrated, showing the prominence of this remedy for developing high-energy-density LMBs.

Automated summary

By incorporating nickel (Ni) seeds in the bulk Li anode with tailored interfacial chemistry, this study demonstrates improved charge transfer dynamics and the formation of a customized electrolyte interface, enabling the development of high-energy-density lithium metal batteries (LMBs).