Defect-abundant commercializable 3D carbon papers for fabricating composite Li anode with high loading and long life

Abstract

Lithium metal is considered as the most promising anode material due to its high theoretical specific capacity and low electrochemical reduction potential. However, both lithium dendritic formation and huge volume change upon cycling severely discount its practical longevity. Various strategies have been proposed recently to address the electrochemical/chemical stabilities of Li anode by fabricating composite structures with somewhat compromising the energy density. Herein, abundant structural defects were successfully introduced into the commercial 3D carbon paper (3D CP), which was then employed as the matrix (3D CP/D) to construct Li composite anode (3D CP/D-Li). Experimental observations reveal that the oxygen treatment greatly improves the lithiophilicity of 3D CP/D, which not only enables the uniform loading of molten lithium, but also facilitates lithium stripping and plating upon cycling. Symmetric cells with the 3D CP/D-Li could be operated over ∼ 600 cycles under an ultrahigh current density of 12 mA cm−2. Utilizing commercial LiNi0.8Co0.15Al0.05O2 (NCA) as cathode material (with a high mass loading of ∼ 21.93 mg cm−2), the assembled cell (NCA | 3D CP/D-Li) exhibits an improved capacity retention of 74.4% and a high reversible capacity of 160.2 mAh g−1 after 500 cycles compared with that selecting bare lithium as anode (34.4% and 72.2 mAh g−1). This work establishes a novel strategy to fabricate robust Li composite anode with high mass loading and long life, which may shed light in the development of composite anode for next-generation high-energy-density lithium-ion batteries.