3D composite lithium metal with multilevel micro-nano structure combined with surface modification for stable lithium metal anodes

Combined modified lithium metal composite anode with multilevel micro-nano structure was synthesized by infusion of molten lithium into Cu foam and coating with zinc fluoride. The lithium metal composite anode was used for lithium batteries, the electrochemical performances reveal that surface modification reduces interfacial side reaction and multilevel micro-nano structure suppresses the growth of lithium dendrite. [Display omitted] •The strategy of combining bulk and surface modification is proposed.•The multilevel micro-nano structure of lithium metal composite is formed.•The excellent performance of symmetric cell is achieved. Lithium (Li) metal has extremely high theoretical specific capacity and low redox potential, which can greatly improve energy density of Li battery. Nevertheless, some troubles including Li dendrite, parasitic reaction and volumetric change extremely restrict its practical application. Herein, a strategy of combining 3D composite lithium metal and surface modification is proposed for solving these issues simultaneously. The 3D composite lithium metal electrode is synthesized by infusing molten Li into Cu foam, and multilevel micro-nano structure is obtained by alloying reaction between Li and surface part of Cu foam, which can be used as three-dimensional (3D) scaffold with high specific surface area. The surface modification of coating zinc fluoride (ZnF2) is used as artificial solid electrolyte interphase (SEI). The symmetric cell using modified composite Li anode exhibits stable electrochemical performance and long cycling lifespan. And the excellent performance of LiCoO2 (LCO) cell (average 121 mAh g−1) is achieved, compared to pristine Li of 114 mAh g−1.