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: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.
authors: Chenfei
authors: C
authors: Shen
authors: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.|National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States.
authors: Mingyuan
authors: M
authors: Ge
authors: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors: Langli
authors: L
authors: Luo
authors: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.
authors: Xin
authors: X
authors: Fang
authors: Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States.
authors: Yihang
authors: Y
authors: Liu
authors: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.
authors: Anyi
authors: A
authors: Zhang
authors: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.
authors: Jiepeng
authors: J
authors: Rong
authors: Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, United States.
authors: Chongmin
authors: C
authors: Wang
authors: Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California 90089, United States.|Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, United States.
authors: Chongwu
authors: C
authors: Zhou