Fe3N@N-doped graphene as a lithiophilic interlayer for highly stable lithium metal batteries

Abstract

Lithium (Li) metal anode is of great importance for high-energy rechargeable batteries owing to its ultrahigh theoretical capacity. However, the Li dendrite growth during the repetitive charge/discharge process will impale the separator resulting in short-circuiting and serious safety issues. To effectively suppress Li dendrite growth, for the first time we present a novel lithiophilic interlayer on commercial PP separator, which is constructed by Fe3N nanoparticles embedded and wrapped in N-doped graphene nanosheets (Fe3N@NG). The Fe3N@NG functionalized separator displays excellent electrolyte wettability, high Li ionic conductivity and ion transference number, which function synergistically to suppress Li dendrite growth. Meanwhile, the DFT calculation demonstrates that there exists a stronger interaction between Li atoms and Fe3N@NG, which can provide the deposition sites, resulting in uniform and compact Li plating. Above ameliorating merits accompany an ultra-long-life of 2300 h at 5 mA cm−2 for the Li//Li symmetric cells with Fe3N@NG functionalized separators. Moreover, the Li//LFePO4 full cell delivers superior long-term cyclic stability and ultralow capacity decay rate of 0.08%/cycle even at 2C. This work provides an innovative strategy to rationally design and new insights towards functional lithiophilic interlayer to efficiently suppress Li dendrite growth for Li metal batteries.