Improving Li anode performance by a porous 3D carbon paper host with plasma assisted sponge carbon coating

Abstract Li metal has been regarded as the most promising anode material for next high-energy batteries. However, the high capacity of Li metal (3860 mA h g−1) is severely counteracted by the loss in side reactions at its unstable Li/electrolyte interface. Herein, we prepare a special composite, by growing a high-quality Sponge Carbon layer onto a 3D Carbon Paper (SCCP). During initial stage of Li deposition, Li ions are intercalated in the carbon paper skeletons then followed by Li metal plating, enabling the entire Li metal deposition underneath the sponge carbon layer. Such a conformal surface accommodation with modulated Li metal deposition provides highly stable Li/electrolyte interfaces. The Coulombic efficiencies for Li plating at 3 and 4 mA h cm−2 are as high as 98–99% in the SCCP, obtained in corrosive carbonate electrolytes. Paired with high areal capacity LiFePO4 cathodes (~ 1.8 mA h cm−2), a SCCP protected Li foil can still keep its metal luster after 650 cycles, in sharp contrast to a side products covered surface observed on naked Li foil after 400 cycles. These results clearly demonstrate the ability of the SCCP to stabilize Li surface, which may be applied in Li metal batteries for long-term operation.