Optimizing Li Plating/Stripping Procedure via Robust Nanospherical Gradient Lithiophilic Decoration for Lithium Metal...

Lithium metal batteries (LMBs) are hindered by dendrite growth and volume expansion. While 3D hosts offer solutions, uniform lithiophilicity often leads to surface-preferred deposition and internal space wastage. Herein, we report amorphous carbon-coated ferroferric oxide (Fe₃O₄@C) nanospheres designed with a radial lithiophilicity gradient. The strong lithiophilic Fe₃O₄/C core and weaker lithiophilic carbon shell create a thermodynamic driving force, guiding Li ions to penetrate the outer layer and achieve "bottom-up" or "inside-out" deposition. This gradient mechanism, coupled with the robust solid core and flexible shell, effectively suppresses Li dendrite growth and accommodates volume expansion through synergistic mechanical stress. As a result, the half-cell achieves a stable Coulombic efficiency of 97.17% at 1 mAh cm^-2, while the symmetrical cell demonstrates long-term cycling stability over 2000 h. Furthermore, the LFP full-cell retains a 93.4% capacity after 150 cycles at 1 C. This work highlights the critical role of radial gradient lithiophilicity in ensuring uniform, deep-level Li deposition for practical LMBs.