TY - JOUR
T1 - Understanding the influence of electrolyte additives on the electrochemical performance and morphology evolution of silicon nanowire based lithium-ion battery anodes
AU - Kennedy, Tadhg
AU - Brandon, Michael
AU - Laffir, Fathima
AU - Ryan, Kevin M.
N1 - Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2017
Y1 - 2017
N2 - 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.
AB - 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.
KW - Electrolyte additive
KW - Lithium-ion battery
KW - Nanowire
KW - Silicon anode
KW - Solid electrolyte interface layer
KW - X-ray photoelectron spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85020291941&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2017.05.093
DO - 10.1016/j.jpowsour.2017.05.093
M3 - Article
AN - SCOPUS:85020291941
SN - 0378-7753
VL - 359
SP - 601
EP - 610
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -