Covalently bonded 3D rebar graphene foam for ultrahigh-areal-capacity lithium-metal anodes by in-situ loose powder metallurgy synthesis

Abstract

A free-standing covalently bonded CNTs/graphene foam (LPM-3D rebar GF) is developed by using an in-situ loose powder metallurgy templates method for high-performance dendrite-free Li metal anodes. The LPM-3D rebar GF possesses a macroporous structure with interconnected porous pipelines. The homogeneously dispersed CNTs can induce an in-situ growth for covalently bridging graphene sheets, resulting in the increase of electrical conductivity, structural stability, and active Li nucleation sites. With the guidance of CNTs, Li metal deposit preferentially on the junctions of CNTs and graphene to achieve a uniform deposition and avoid the formation of Li dendrites effectively, which is verified by both experiments and first-principle calculations. As the anode of Li metal battery, the LPM-3D rebar GF shows outstanding cycling stability even at 20 mA cm−2 for 20 mA h cm−2. Notably, this anode can still operate 90 cycles at 30 mA h cm−2 with a Coulombic efficiency (CE) of >98%. These properties indicate promising prospects of LPM-3D rebar GF as a new and dendrite-free anode with large areal capacity for high-performance Li metal batteries, and in other fields requiring 3D carbon monoliths including fuel cells and sodium-ion batteries.