Balanced 3D host structure of graphitic carbon, amorphous carbon, and SnO2 for uniform and stable lithium deposition in lithium metal anodes

초록

Stable, high-performance lithium metal anodes (LMAs) are crucial for building next-generation energy storage systems. Employing a 3D host structure to store lithium prevents lithium dendritic growth and mitigates the volume expansion associated with lithium deposition, thereby enhancing the cycling stability and safety of LMAs. Here, a 3D host structure is synthesized via a multistep process involving cobalt-catalyzed graphitization, Sn salt impregnation, and heat treatment. This 3D carbon-based host structure comprising balanced graphitic carbon, amorphous carbon, and SnO2 nanoparticles (C-SnO2-350) enables uniform lithium deposition, reduces dendritic lithium growth, and minimizes side reactions. The C-SnO2-350 electrode demonstrates exceptional cycling stability, rate capability, and prolonged cycling life, maintaining over 99 % coulombic efficiency in asymmetric cell tests and stable voltage hysteresis in symmetric cell tests. Compared to cells with lithium anodes deposited on bare Cu foil, full cells paired with LiNi0 & sdot;6Co0 & sdot;2Mn0 & sdot;2O2 cathodes exhibit superior capacity retention and coulombic efficiency. Mechanistic studies reveal the synergistic effects of the carbon framework and lithiophilic SnO2 nanoparticles, which facilitate efficient lithium nucleation and deposition. This study highlights the potential of a balanced composite comprising graphitic carbon, amorphous carbon, and lithiophilic SnO2 as a practical 3D host structure for LMAs, offering improved electrochemical performance and stability under demanding conditions.

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