Understanding the lithiation/delithiation mechanism of Si1-xGex alloys
Journal article, 2017

GexSi1-x alloys have demonstrated synergetic effects as lithium-ion battery (LIB) anodes, because silicon brings its high lithium storage capacity and germanium its better electronic and Li ion conductivity. Previous studies primarily focused on intricate nanostructured alloys with high costs of production, but here we studied the simpler Si0.5Ge0.5 alloy as a composite electrode. The electrochemical mechanism is explored by a combination of in situ and operando techniques such as powder X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Raman spectroscopy and Li-7 solid state nuclear magnetic resonance spectroscopy (NMR), all providing unique and complementary information about phase transformations during cycling. In this way amorphization of c-Si0.5Ge0.5 upon lithiation (discharging) and crystallization of a new phase at the end of the discharge have been identified. Additionally, an evolution of the refined cell parameters was observed and related to an overlithiation process. The crystallinity of Si0.5Ge0.5 was not restored upon charging (delithiation) and an amorphous phase was obtained. Lastly, an improved understanding of the electrochemical mechanism of Si1-xGex alloys is mandatory for assessing their viability as LIB anodes.

Solid-State NMR

In-Situ XRD

Silicon

Anode Materials

Raman-Spectroscopy

Curve Resolution

Lithium-Ion Batteries

Multivariate

Structural-Changes

Thin-Film Electrodes

X-Ray-Diffraction

Author

L. C. Loaiza

University of Picardie Jules Verne

E. Salager

Universite d'Orleans

Centre national de la recherche scientifique (CNRS)

N. Louvain

University of Montpellier

Centre national de la recherche scientifique (CNRS)

Athmane Boulaoued

Chalmers, Physics, Condensed Matter Physics

A. Iadecola

Centre national de la recherche scientifique (CNRS)

Patrik Johansson

Chalmers, Physics, Condensed Matter Physics

L. Stievano

University of Montpellier

Centre national de la recherche scientifique (CNRS)

University of Picardie Jules Verne

V. Seznec

Centre national de la recherche scientifique (CNRS)

University of Picardie Jules Verne

L. Monconduit

University of Picardie Jules Verne

Centre national de la recherche scientifique (CNRS)

University of Montpellier

Journal of Materials Chemistry A

20507488 (ISSN) 20507496 (eISSN)

Vol. 5 24 12462-12473

Subject Categories

Materials Chemistry

DOI

10.1039/c7ta02100c

More information

Latest update

9/7/2018 1