Recognizing the nitrogen/oxygen co-doped lithiophilicity chemistry toward molten Li infusion for fabricating composite Li metal anode

Structured Li anode is a strong candidate for reviving lithium metal anode in high-energy-density rechargeable batteries, suppressing the dendrite growth and stabilizing the volume change. However, the lithiophilicity chemistry and lightweight design of substrates remain a challenge to assemble composited anode. Herein, we report a N/O co-doped carbon fiber (NOCF) and its intrinsic lithiophilicity chemistry for fabricating Li structured anode (CF/Li). The experimental lithiophilicity comparison of different N-functional groups demonstrates that the increasing ratio of quaternary N and N-oxides can turn a lithiophobic surface into the lithiophilic NOCF than pyrrolic and pyridine N as previously estimated. Thanks to the lightweight NOCF, the fabricated CF/Li anode achieves 3142 mAh g−1 capacity, equivalent to 82% theoretical capacity of lithium metal. Notably, the CF/Li composited anode presents outstanding electrochemical and structural stability with inhibited dendrites during the Li stripping/plating process. Even at an ultrahigh current density of 10 mA cm−2, the CF/Li still exhibits lower polarization (141.1 mV) and a smoother voltage profile for 500 cycles. In Li-LFP cells, the CF/Li also delivers better cycling and rate performance than the commercial Li foils.