Premium
Best Performing SiGe/Si Core‐Shell Nanoparticles Synthesized in One Step for High Capacity Anodes
Author(s) -
Desrues Antoine,
Alper John P.,
Boismain Florent,
Zapata Dominguez Diana,
Berhaut Christopher,
Coulon PierreEugène,
Soloy Adrien,
Grisch Frédéric,
Tardif Samuel,
Pouget Stéphanie,
Lyonnard Sandrine,
Haon Cédric,
HerlinBoime Nathalie
Publication year - 2019
Publication title -
batteries and supercaps
Language(s) - English
Resource type - Journals
ISSN - 2566-6223
DOI - 10.1002/batt.201900094
Subject(s) - materials science , nanoparticle , silane , heterojunction , alloy , anode , nanostructure , chemical engineering , germanium , silicon , electrochemistry , nanotechnology , optoelectronics , electrode , composite material , chemistry , engineering
Silicon‐germanium nanostructures are promising anode materials for high stability, high capacity, and fast cycling Li‐ion batteries. In this work, we report on the outstanding performance of new SiGe/Si core@shell nanoparticle heterostructures synthetized in one step by laser pyrolysis of silane and germane. By tuning the silane to germane ratio, the composition of Si 100‐ x Ge x alloy was readily adjusted. Nanoparticles with x =0, 20, 47, 77, and 100 were investigated and the composition of each alloy (including internal mixed phases) was confirmed by X‐ray diffraction and energy‐dispersive X‐ray spectroscopy. The electrochemical performances of the Si 100‐ x Ge x alloys were evaluated by cycling half cell batteries from C/5 to 5 C. The optimal trade‐off between stability and capacity was obtained in Si 53 Ge 47 core shell nanoparticles alloy. This material exhibits the best performance reported so far for SiGe compounds, with a reversible specific capacity of 1695 mAh.g −1 after 60 cycles (90 % of its initial value). The (de)alloying properties of this optimal Si 53 Ge 47 heterostructure were followed by operando synchrotron WAXS measurements, suggesting sequential lithiation of the various phases present in the material. The alloying process, combined with the realization of peculiar nanostructures composed of a Ge‐rich core and a Si‐rich shell, therefore allow to reach electrochemical properties suited for a practical application in energy storage device.