Graphene anchored on Cu foam as a lithiophilic 3D current collector for a stable and dendrite-free lithium metal anode

Abstract

Lithium (Li) metal has been considered as the most promising anode material for high-energy-density batteries. However, its practical application has been affected by the growth of dendrites and volume change, which results in low coulombic efficiency (CE) and safety concerns during repeated Li plating/stripping. Herein, we show that a 3D current collector with graphene anchored on copper foam (GN@Cu foam) can induce uniform and stable Li deposition over a wide current density range and long-term cycling. It can maintain a CE of 97.4% for 150 cycles at a current density of 2 mA cm-2 in half cells and afford an areal capacity of 6 mA h cm-2 at 6 mA cm-2 in symmetric cells. When cycling at 0.5 mA cm-2, the current collector presents a CE as high as 98.6% for 250 cycles in half cells and a low voltage hysteresis of 10 mV over 2000 h in symmetric cells. The GN@Cu foam serves as a conductive skeleton with moderate specific surface area and lithiophilic sites to store Li, exhibiting a dendrite-free morphology after long term cycling. This study provides novel insights into modifying a 3D current collector with lithiophilic materials towards an advanced and stable Li metal anode.