Facile decoration of fluorinated metal–organic frameworks on copper foil for regulated lithium deposition and robust solid electrolyte interface

Abstract

Lithium metal is one of the most promising anode materials for Li-ion batteries. However, lithium metal anodes suffer from low coulomb efficiency, short cycle life, and even serious safety issues, owing to the incompatible Cu/Li interface and brittle solid electrolyte interface (SEI). A facile strategy is proposed to construct stable lithium metal anodes by regulating both the Cu/Li interface and SEI membrane with a thin layer of copper-tetrafluoroterephthalate (CuTFBDC), which can guide the uniform lithium deposition and the LiF-rich SEI. The prepared CuTFBDC@Cu foils can be applied as current collectors, and the assembled Li@CuTFBDC@Cu//Li symmetric cell exhibits a stable performance at a current density of 0.5 mA cm⁻² for more than 3000 h, with a small voltage hysteresis of less than 11.5 mV, surpassing that of the bare Cu foil. The assembled Li@CuTFBDC@Cu//LFP (LiFePO₄) full cell proceeds smoothly for 200 cycles at a current density of 2 C with a specific capacity of 133.8 mAh/g, and the capacity can be maintained at 125.29 mAh/g after 250 cycles. This facile strategy can provide a solution for both the Cu/Li interface and SEI membrane, showing an excellent prospect for practical applications in lithium metal batteries.