Nanoperforated graphene microspheres decorated with zinc oxide as a stable host for dendrite-free lithium metal anodes

초록

Lithium (Li) metal emerged as the most promising anode for next-generation high-energy-density batteries, although its practical application is hindered by dendritic growth, resulting in internal short circuits or cell failure. Here, we propose a novel Li host material based on nanoperforated graphene microspheres (PGM), which comprise lithiophilic carbonyl (C=O) groups at their edge sites, further composited with cost-effective and lithiophilic Zinc Oxide (ZnO) nanoparticles. The synthesized ZnO/PGM composites offer two key advantages: (1) ZnO and C=O groups reduce the nucleation barrier for Li, promoting uniform deposition; (2) the three-dimensional spherical assembly of nanoperforated graphene sheets reduces the tortuosity of Li-ion pathways, suppressing localized deposition. Li-plated ZnO/PGM symmetric cells achieved a low Li plating/stripping overpotential of similar to 18.87 mV for 700 cycles. Furthermore, dendrite-free morphology was retained after 300 cycles. Full cells paired with LiFePO4 cathode retained a discharge capacity of 124.8 mAh g(-1) after 250 cycles at 1C-rate (capacity retention of 87.3%). These results demonstrate that the PGM, which overcomes the limitations of conventional graphene-based Li hosts, enables the facile construction of dendrite-free Li metal anodes by compositing with ZnO nanoparticles.

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