Dendrite-Free lithium electrode enabled by graphene aerogels with gradient porosity

Lithium metal is the most attractive anode material owing to its lowest electrochemical potential and high theoretical specific capacity. However, uncontrolled dendrite growth leads to severe safety issues and poor electrochemical stability, hindering its practical application. Herein, we report a dendrite-free and reversible Li metal anode enabled by graphene aerogel (GA) host with three-dimensional gradient porous structure. The gradient porous structure facilitates reversible Li plating/stripping with high Li/carbon mass ratio (Li/C = 5) and realizes uniform Li distribution on the electrode surface. This approach achieves a stable voltage profile for a long lifespan (1300 h at 2 mA cm−2 for 2 mAh cm−2 and 1000 h at 5 mA cm−2 for 3 mAh cm−2) with superior high symmetric cumulative capacity (2500 mAh cm−2). Coupling the LiGA anode with a LiFePO4 (LFP) cathode, a stable cycling of the full LiGA-LFP cells for 200 cycles at 2 C were achieved, demonstrating the promising practical applications of LiGA in advanced rechargeable batteries.