A porous lithium metal anode with an artificial solid electrolyte interface fabricated by a facile process

Abstract

Lithium metal batteries (LMBs) have been considered a next-generation energy storage system. However, dendrite growth on lithium metal anode has critical issues with poor Coulombic efficiency and safety problems such as short-circuiting. Moreover, the continuous growth of dendrites leads to severe volume expansion of the electrode. To solve these problems, we suggest a lithium metal anode with a porous structure covered by artificial solid electrolyte interphase (SEI) layer. The porous lithium metal anode with the artificial SEI layer is prepared simply by dissolving lithium salt (lithium bis(fluorosulfonyl)imide, LiFSI) from a pellet of the mixture of lithium metal powder and lithium salt. In contrast to planar lithium metal foil, the porous structure decreases areal current density and reduces the possibility to form long dendrites penetrating the separator. Also, the artificial SEI layer with a porous structure induces uniform plating of lithium above and inside the lithium metal anode. As a result, the symmetric cells with the porous lithium metal anode show enhanced cycle life and rate capability compared to the anode prepared with bare lithium metal powder. Furthermore, the full cell assembled with the porous lithium metal anode and NCM811 cathode also shows significantly higher rate capability than the bare lithium metal anode. Our results provide a better understanding for designing a porous lithium metal anode with an inherent SEI layer for high-capacity and high-rate lithium metal batteries.