The Influence of PMS-Additive on the Electrode/Electrolyte Interfaces in LiFePO4/Graphite Li-Ion Batteries
Artikel i vetenskaplig tidskrift, 2013

The influence of a film-forming additive, propargyl methanesulfonate (PMS), on electrochemical performance and electrode/electrolyte interface composition of LiFePO4/graphite Li-ion batteries has been studied. Combined use of in-house X-ray photoelectron spectroscopy (XPS) and soft and hard X-ray photoelectron spectroscopy (PES) enabled nondestructive depth profiling at four different probing depths in the 2-50 nm range. Cells cycled with PMS and LiPF6 in ethylene carbonate/diethyl carbonate (EC/DEC) were compared to a reference sample cycled without PMS. In the first cycle, PMS cells showed a higher irreversible capacity, which is explained by formation of a thicker solid electrolyte interphase (SEI). After three cycles, the SET thicknesses were determined to be 19 and 25 nm for the reference and PMS samples, respectively. After the initial cycling, irreversible losses shown by the PMS cells were lower than those of the reference cell. This could be attributed to a different SET composition and lower differences in the amount of lithium between lithiated and delithiated electrodes for the PMS sample. It was suggested that PMS forms a triple-bonded radical on reduction, which further reacts with the electrolyte. The PMS additive was shown to influence the chemical composition at the positive electrode/electrolyte interface. Thicker interface layers with higher C-O and smaller LiF contributions were formed on LiFePO4 cycled with PMS.

functional electrolytes

ray photoelectron-spectroscopy

graphite-electrodes

sei

electrochemical-behavior

ethylene carbonate

surface-chemistry

lithium

mechanisms

thermal-stability

Författare

K. C. Hogstrom

Uppsala universitet

S. Malmgren

Uppsala universitet

M. Hahlin

Uppsala universitet

H. Rensmo

Uppsala universitet

Frederic Thebault

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Patrik Johansson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

K. Edstrom

Uppsala universitet

Alistore - European Research Institute

Journal of Physical Chemistry C

1932-7447 (ISSN) 1932-7455 (eISSN)

Vol. 117 45 23476-23486

Ämneskategorier

Materialteknik

Styrkeområden

Transport

Energi

Materialvetenskap

DOI

10.1021/jp4045385