Peer-Reviewed Journal Details
Mandatory Fields
Kennedy, T,Brandon, M,Laffir, F,Ryan, KM
2017
August
Journal Of Power Sources
Understanding the influence of electrolyte additives on the electrochemical performance and morphology evolution of silicon nanowire based lithium-ion battery anodes
Published
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Optional Fields
Lithium-ion battery Electrolyte additive Solid electrolyte interface layer Silicon anode Nanowire X-ray photoelectron spectroscopy RAY PHOTOELECTRON-SPECTROSCOPY THIN-FILM ELECTRODE VINYLENE CARBONATE VC LI-ION FLUOROETHYLENE CARBONATE SURFACE-CHEMISTRY REDUCTION-MECHANISM GRAPHITE-ELECTRODES GERMANIUM NANOWIRES THERMAL-STABILITY
359
601
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Here we report new insights into the effect various electrolyte additives have on the cycling stability and rate capability of Si nanowire (NW) Li-ion battery anodes. The additives tested were vinylene carbonate, vinyl ethylene carbonate, fluoroethylene carbonate and lithium bis(oxalato) borate. All four significantly improve the capacity retention of the electrodes over 250 cycles compared to the additive-free electrolyte, with vinylene carbonate being the outstanding performer. The results provide a new understanding of the cycling behaviour of Si in the presence of electrolyte additives, revealing that not only is the stability of the SEI layer affected but that this consequently has a profound influence on the morphology evolution and chemical composition of the Si active material. Ex-situ characterisation of the electrodes post-cycling demonstrates that the improvement in cycling stability arises as the additives minimise irreversible decomposition reactions at the surface and facilitate a transformation from a NW morphology into a porous sponge-like network. This transformation process does not occur in the absence of any stable SEI forming additives as instability in the passivating layer leads to the continuous and irreversible consumption of Si to form Li silicates. (C) 2017 Elsevier B.V.All rights reserved.
10.1016/j.jpowsour.2017.05.093
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