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Nano Research

Article Title

Water-soluble-template-derived nanoscale silicon nanoflake and nano-rod morphologies: Stable architectures for lithium-ion battery anodes

Keywords

silicon, nanoflakes, nanorods, water-soluble template, NaCl

Abstract

ABSTRACT Earth abundant and economical rock salt (NaCl) particles of different sizes (3 m and 5–20 m) prepared by high energy mechanical milling were used as water-soluble templates for generation of Si with novel nanoscale architectures via low pressure chemical vapor deposition (LPCVD). Si nanoflakes (SiNF) comprising largely amorphous Si (a-Si) with a small volume fraction of nanocrystalline Si (nc-Si), and Si nanorods (SiNR) composed of a larger volume fraction of crystalline Si (c-Si) and a small volume fraction of a-Si resulted from modification of the NaCl crystals. SiNF yielded first-cycle discharge and charge capacities of ~2,830 and 2,175 mAh·g–1, respectively, at a current rate of 50 mA·g–1 with a first-cycle irreversible loss (FIR loss) of ~15%–20%. SiNR displayed first-cycle discharge and charge capacities of ~2,980 and ~2,500 mAh·g–1, respectively, at a current rate of 50 mA·g–1 with an FIR loss of ~12%–15%. However, at a current rate of 1 A·g–1, SiNF exhibited a stable discharge capacity of ~810 mAh·g–1 at the end of 250 cycles with a fade rate of ~0.11% loss per cycle, while SiNR showed a stable specific discharge capacity of ~740 mAh·g–1 with a fade rate of ~0.23% loss per cycle. The morphology of the nanostructures and compositions of the different phases/phase of Si influence the performance of SiNF and SiNR, making them attractive anodes for lithium-ion batteries.

Graphical Abstract

Publisher

Tsinghua University Press

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