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Title: In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures

Abstract

In this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li15Si4 phase while porous Si nanoparticles and nanowires transform to amorphous LixSi phase, which is due to the effect of domain size on the stability of Li15Si4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1340852
Report Number(s):
PNNL-SA-115171
Journal ID: ISSN 2045-2322; 48379; KP1704020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Scientific Reports; Journal Volume: 6
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Shen, Chenfei, Ge, Mingyuan, Luo, Langli, Fang, Xin, Liu, Yihang, Zhang, Anyi, Rong, Jiepeng, Wang, Chongmin, and Zhou, Chongwu. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures. United States: N. p., 2016. Web. doi:10.1038/srep31334.
Shen, Chenfei, Ge, Mingyuan, Luo, Langli, Fang, Xin, Liu, Yihang, Zhang, Anyi, Rong, Jiepeng, Wang, Chongmin, & Zhou, Chongwu. In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures. United States. doi:10.1038/srep31334.
Shen, Chenfei, Ge, Mingyuan, Luo, Langli, Fang, Xin, Liu, Yihang, Zhang, Anyi, Rong, Jiepeng, Wang, Chongmin, and Zhou, Chongwu. Tue . "In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures". United States. doi:10.1038/srep31334.
@article{osti_1340852,
title = {In Situ and Ex Situ TEM Study of Lithiation Behaviours of Porous Silicon Nanostructures},
author = {Shen, Chenfei and Ge, Mingyuan and Luo, Langli and Fang, Xin and Liu, Yihang and Zhang, Anyi and Rong, Jiepeng and Wang, Chongmin and Zhou, Chongwu},
abstractNote = {In this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li15Si4 phase while porous Si nanoparticles and nanowires transform to amorphous LixSi phase, which is due to the effect of domain size on the stability of Li15Si4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.},
doi = {10.1038/srep31334},
journal = {Scientific Reports},
number = ,
volume = 6,
place = {United States},
year = {Tue Aug 30 00:00:00 EDT 2016},
month = {Tue Aug 30 00:00:00 EDT 2016}
}
  • Here in this work, we study the lithiation behaviours of both porous silicon (Si) nanoparticles and porous Si nanowires by in situ and ex situ transmission electron microscopy (TEM) and compare them with solid Si nanoparticles and nanowires. The in situ TEM observation reveals that the critical fracture diameter of porous Si particles reaches up to 1.52 μm, which is much larger than the previously reported 150 nm for crystalline Si nanoparticles and 870 nm for amorphous Si nanoparticles. After full lithiation, solid Si nanoparticles and nanowires transform to crystalline Li 15Si 4 phase while porous Si nanoparticles and nanowiresmore » transform to amorphous Li xSi phase, which is due to the effect of domain size on the stability of Li 15Si 4 as revealed by the first-principle molecular dynamic simulation. Ex situ TEM characterization is conducted to further investigate the structural evolution of porous and solid Si nanoparticles during the cycling process, which confirms that the porous Si nanoparticles exhibit better capability to suppress pore evolution than solid Si nanoparticles. The investigation of structural evolution and phase transition of porous Si nanoparticles and nanowires during the lithiation process reveal that they are more desirable as lithium-ion battery anode materials than solid Si nanoparticles and nanowires.« less
  • Rational design of silicon and carbon nanocomposite with a special topological feature has been demonstrated to be a feasible way for mitigating the capacity fading associated with the large volume change of silicon anode in lithium ion batteries. Although the lithiation behavior of silicon and carbon as individual component has been well understood, lithium ion transport behavior across a network of silicon and carbon are still lacking. In this paper, we probe the lithiation behavior of silicon nanoparticles attached to and embedded in a carbon nanofiber using in-situ TEM and continuum mechanical calculation. We found that aggregated silicon nanoparticles showmore » contact flattering upon initial lithiation, which is characteristically analogous to the classic sintering of powder particles by neck-growth mechanism. As compared with the surface-attached silicon particle, particles embedded in the carbon matrix show delayed lithiation. Depending on the strength of the carbon matrix, lithiation of the embedded silicon nanoparticle can lead to the fracture of the carbon fiber. These observations provide insights on lithium ion transport in the network structured composite of silicon and carbon, and ultimately provide fundamental guidance for mitigating the failure of battery due to the large volume change of silicon anode.« less
  • To utilize high-capacity Si anodes in next-generation Li-ion batteries, the physical transformations during the Li-Si reaction must be better understood. Here, in-situ transmission electron microscopy is used to observe the lithiation/delithiation of amorphous Si nanospheres; amorphous Si is an important anode material that has been studied less than crystalline Si. Unexpectedly, the experiments reveal that the first lithiation occurs via a two-phase mechanism, which is contrary to previous understanding and has important consequences for mechanical stress evolution during lithiation. Based on kinetics measurements, this behavior is suggested to be due to the rate-limiting effect of Si-Si bond breaking. In addition,more » the results show that amorphous Si has more favorable kinetics and fracture behavior when reacting with Li than does crystalline Si, making it advantageous to use in battery electrodes. Amorphous spheres up to 870 nm in diameter do not fracture upon lithiation; this is much larger than the 150 nm critical fracture diameter previously identified for crystalline Si spheres.« less