Synergistic Regulation of Intrinsic Lithiophilicity and Mass Transport Kinetics of Non‐Lithium‐Alloying Nucleation Sites for Stable Operation of Low N/P Ratio Lithium Metal Batteries

Constructing functional materials on a 3D host is an efficient strategy to tackle issues of lithium (Li) metal anodes. Although non‐Li‐alloying materials provide structural stability during cycling due to reduced lattice distortions, low lithiophilicity and sluggish mass transport kinetics limit their functionality. Herein, a synergistic strategy is proposed to improve intrinsic lithiophilicity and mass transport kinetics of non‐Li‐alloying nucleation sites and demonstrate its remarkable efficacy. Two carbon fiber (CF) hosts coated by non‐Li‐alloying nanosheets with and without oxygen‐enriched carbon filler (OCF) as lithiophilicity and mass transport booster (OCF‐DSC@CF and DSC@CF, respectively) are constructed and their physiochemical properties are systematically evaluated to reveal the efficacy of OCF. By advanced characterization techniques, including 3D tomography and location‐dependent electron energy loss spectroscopies, the complex heterostructure of OCF‐DSC@CF with distinctive roles of each constituent is clearly identified. As verified by theoretical and electrochemical analyses, the incorporation of OCF endows OCF‐DSC@CF with substantially improved lithiophilicity and mass transport kinetics. Moreover, OCF‐DSC@CF induces a multifunctional SEI enriched with LiF and LiCx, which exhibits well‐balanced electrical resistivity and ionic conductivity. Benefiting from these attributes, OCF‐DSC@CF exhibits an unprecedented cyclability under a low N/P ratio of 1.8, achieving 700 cycles at 0.5C with an exceptional capacity retention of 97.8%. The poor intrinsic lithiophilicity and mass transport kinetics of non‐Li‐alloying nucleation sites are synergistically regulated by the incorporation of OCF. The complex heterostructure of OCF‐DSC@CF is scrutinized by advanced characterization techniques, including location‐dependent EELS and 3D tomography. Theoretical and experimental investigations verify the efficacy of OCF as a lithiophilicity‐ and mass transport kinetics booster.