“ZnO-in-Carbon-Cage” Decorated Carbon Fibers as a Stable Lithium Host with Enhanced Kinetics for Lithium Metal Batteries

Lithium (Li) metal anodes (LMAs), which show a great potential in constructing high-specific-energy-density Li metal batteries (LMBs), have abstracted wide research interest. However, the generation of Li dendrites and the repeated change of volume upon Li plating/stripping severely block the practical commercialization of LMBs. Herein, the functional carbon fibers (CFs) decorated with ZnO embedded carbon cage (ZnO@C-d-CFs) were fabricated successfully by a two-step route including the in-situ growth of Zn-based metal organic frameworks (MOFs) and subsequent carbonization process, which enriched the lithiophilic sites of CFs host and improved Li+ kinetics of Li+ plating/stripping. Markedly, our designed ZnO@C-d-CFs possessed an obvious surface stability for Li+ plating/stripping (e. g., 1000 cycles with a CE of ~100% for ZnO@C-d-CFs||Li cell, 1200 h for Li-ZnO@C-d-CFs||Li-ZnO@C-d-CFs cell), and demonstrated a great potential in practical LMBs (e.g., a low-capacity decay of 0.067 mAh g-1 per cycle within the monitored 900 cycles in Li-ZnO@C-d-CFs||LiFePO₄ (LFP) cell). The impressive results verified an effectiveness of surface modification on Li host to boost the stable LMAs.