Synergistic Design of a SiO2-CNT-Amorphous Carbon 3D Host for Stable SEI Formation and Long-Term Cycling Stability of Lithium Metal Anodes

초록

Lithium metal batteries (LMBs) offer exceptionally high energy density but suffer from dendritic lithium growth and large volume changes. Employing three-dimensional (3D) host electrodes is a promising strategy to mitigate these challenges. Here, a 3D composite host comprising conductive carbon nanotubes (CNTs) and amorphous carbon with uniformly distributed SiO2 (SiO2@AC-CNT) is fabricated through spray pyrolysis followed by carbonization. The synergistic integration of SiO2, CNTs, and amorphous carbon optimizes electrical conductivity and lithiophilicity, enabling uniform, dendrite-free lithium deposition, while the amorphous carbon domains promote a Li2CO3-rich solid electrolyte interphase that facilitates lithium-ion transport and suppresses parasitic reactions. In asymmetric cell tests, the SiO2@AC-CNT electrode delivers an average coulombic efficiency of 99.5% for 100 cycles at 2.0 mA cm-2. With a lithium loading of 3.0 mAh cm-2, symmetric cell tests of the SiO2@AC-CNT sustain more than 1300 h at 1.0 mA cm-2 with stable voltage hysteresis and a low overpotential of 18 mV. Paired with a commercial LiFePO4 cathode, the full cell exhibits excellent capacity retention over 600 cycles at 2.0 C, highlighting its potential as a stable and high-performance 3D host for practical LMB.

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