Ionic liquids and oligomer electrolytes based on the B(CN)(4)(-) anion; ion association, physical and electrochemical propertiesw
Artikel i vetenskaplig tidskrift, 2011

The role of B(CN)(4)(-) (Bison) as a component of battery electrolytes is addressed by investigating the ionic conductivity and phase behaviour of ionic liquids (ILs), ion association mechanisms, and the electrochemical stability and cycling properties of LiBison based electrochemical cells. For C(4)mpyrBison and C(2)mimBison ILs, and mixtures thereof, high ionic conductivities (3.4 <= sigma(ion) <= 18 mS cm(-1)) are measured, which together with the glass transition temperatures (-80 <= T(g) <= -76 degrees C) are found to shift systematically for most compositions. Unfortunately, poor solubility of LiBison in these ILs hinders their use as solvents for lithium salts, although good NaBison solubility offers an alternative application in Na(+) conducting electrolytes. The poor IL solubility of LiBison is predicted to be a result of a preferred monodentate ion association, according to first principles modelling, supported by Raman spectroscopy. The solubility is much improved in strongly Li(+) coordinating oligomers, for example polyethylene glycol dimethyl ether (PEGDME), with the practical performance tested in electrochemical cells. The electrolyte is found to be stable in Li/LiFePO(4) coin cells up to 4 V vs. Li and shows promising cycling performance, with a capacity retention of 99% over 22 cycles.

lifepo4 cathode

libob

challenges

batteries

salts

Författare

Johan Scheers

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Jagath Pitawala

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Frederic Thebault

Chalmers, Kemi- och bioteknik, Fysikalisk kemi

Jae-Kwang Kim

Chalmers, Teknisk fysik, Kondenserade materiens fysik

J. H. Ahn

Gyeongsang National University

Aleksandar Matic

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Patrik Johansson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Per Jacobsson

Chalmers, Teknisk fysik, Kondenserade materiens fysik

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 13 33 14953-14959

Ämneskategorier

Fysik

Styrkeområden

Energi

Materialvetenskap

DOI

10.1039/c1cp21062a