TY - JOUR

T1 - Lithiation Products of a Silicon Anode Based on Soft X-ray Emission Spectroscopy

T2 - A Theoretical Study

AU - Lyalin, Andrey

AU - Kuznetsov, Vladimir G.

AU - Nakayama, Akira

AU - Abarenkov, Igor V.

AU - Tupitsyn, Ilya I.

AU - Gabis, Igor E.

AU - Uosaki, Kohei

AU - Taketsugu, Tetsuya

PY - 2018/5/24

Y1 - 2018/5/24

N2 - Because of its exceptional lithium storage capacity, silicon is considered as a promising candidate for anode material in lithium-ion batteries (LIBs). In the present work, we demonstrate that methods of soft X-ray emission spectroscopy can be used as a powerful tool for the comprehensive analysis of the electronic and structural properties of lithium silicides LixSi forming in LIB's anode upon Si lithiation. On the basis of density functional theory and molecular dynamics simulations, it is shown that the coordination number of Si atoms in LixSi decreases with an increase in Li concentration both for the crystalline and amorphous phases. In amorphous a-LixSi alloys, Si tends to cluster, forming Si-Si covalent bonds even at the high lithium concentration. It is demonstrated that the Si-L2,3 emission bands of the crystalline and amorphous LixSi alloys show different spectral dependencies, reflecting the process of disintegration of Si-Si network into Si clusters and chains of the different sizes upon Si lithiation. The Si-L2,3 emission bands of LixSi alloys become narrower and shift toward higher energies with an increase in Li concentration. The shape of the emission band depends on the relative contribution of the X-ray radiation from the Si atoms having different coordination numbers. This feature of the Si-L2,3 spectra of LixSi alloys can be used for the detailed analysis of the Si lithiation process and LIB's anode structure identification.

AB - Because of its exceptional lithium storage capacity, silicon is considered as a promising candidate for anode material in lithium-ion batteries (LIBs). In the present work, we demonstrate that methods of soft X-ray emission spectroscopy can be used as a powerful tool for the comprehensive analysis of the electronic and structural properties of lithium silicides LixSi forming in LIB's anode upon Si lithiation. On the basis of density functional theory and molecular dynamics simulations, it is shown that the coordination number of Si atoms in LixSi decreases with an increase in Li concentration both for the crystalline and amorphous phases. In amorphous a-LixSi alloys, Si tends to cluster, forming Si-Si covalent bonds even at the high lithium concentration. It is demonstrated that the Si-L2,3 emission bands of the crystalline and amorphous LixSi alloys show different spectral dependencies, reflecting the process of disintegration of Si-Si network into Si clusters and chains of the different sizes upon Si lithiation. The Si-L2,3 emission bands of LixSi alloys become narrower and shift toward higher energies with an increase in Li concentration. The shape of the emission band depends on the relative contribution of the X-ray radiation from the Si atoms having different coordination numbers. This feature of the Si-L2,3 spectra of LixSi alloys can be used for the detailed analysis of the Si lithiation process and LIB's anode structure identification.

KW - X-Ray

KW - plane waves

KW - PSEUDOPOTENTIALS

KW - Lithiation anod

KW - LITHIUM-ION BATTERIES

KW - SPACE GAUSSIAN PSEUDOPOTENTIALS

KW - CRYSTALLINE SILICON

KW - ELECTROCHEMICAL LITHIATION

KW - AMORPHOUS-SILICON

KW - 1ST PRINCIPLES

KW - MOLECULAR-DYNAMICS

KW - ELECTRONIC-STRUCTURE

KW - STRUCTURAL-CHANGES

KW - NANOWIRE ANODES

UR - http://www.scopus.com/inward/record.url?scp=85046664228&partnerID=8YFLogxK

UR - http://www.mendeley.com/research/lithiation-products-silicon-anode-based-soft-xray-emission-spectroscopy-theoretical-study

U2 - 10.1021/acs.jpcc.8b00489

DO - 10.1021/acs.jpcc.8b00489

M3 - Article

AN - SCOPUS:85046664228

VL - 122

SP - 11096

EP - 11108

JO - Journal of Physical Chemistry C

JF - Journal of Physical Chemistry C

SN - 1932-7447

IS - 20

ER -