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

• Published in: 纳米研究：英文版 Vol. 10; no. 12; pp. 4284 - 4297
• Main Author: Bharat Gattu;Prashanth Hanumantha Jampani;Moni Kanchan Datta;Ramalinga Kuruba;Prashant N. Kumta
• Format: Journal Article
• Language: English
• Published: 2017
• ISSN: 1998-0124; 1998-0000

Earth abundant and economical rock salt （NaC1） particles of different sizes （〈3 μm and 5-20 μm） 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 NaCI crystals. SiNF yielded first-cycle discharge and charge capacities of -2,830 and 2,175 mAh.g-1, respective134 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 SINK, making them attractive anodes for lithium-ion batteries.