Fig. 2: Active anode (Al-LM) promotes easy Al plating.

a Schematic illustration of the plating of Al adatoms on pure Al versus that on Al-LM. b Active anode behaves differently from a pure Al anode, where no delay in specific capacity and Coulombic efficiency were observed. c Al-LM promotes an ultrafast charging with excellent specific capacity (i_c = 400~1000 A g⁻¹, i_dc = 100 A g⁻¹), where a mere 0.35 s can charge the battery to its full capacity. Compared with pure Al anode, the active anode requests a lower charging voltage and exhibits longer time of discharging duration (i_c = 1000 A g⁻¹, i_dc = 100 A g⁻¹). d Bar graphs of active anode vs. pure Al anode in producing better specific capacity under high rates. Saturation voltage of Al-LM anode was used as  cut-off voltage for both cases. (Inset) Charge and discharge curves at a current density of 100 A g⁻¹ (graphene parameters: 0.025 mg; 0.22 mg cm⁻²). e Electrochemical impedance spectroscopy (EIS) reveals pure Al anode higher resistance than the active anode. f Over-charging of Al-ion batteries with two different anodes (Al vs. Al-LM, i_c = i_dc = 400 A g⁻¹). ① SEM images of full-charging show early morphologies drastically different (scale: 5 µm); and ②-⑤ are optical microscopy images of front- and side-views of plated Al (scale: 100 µm).