The electrochemistry of lithium in ionic liquid/organic diluent mixtures

The electrochemistry of lithium is investigated in a number of electrolytes that consist of a lithium salt dissolved in a combined ionic liquid-organic diluent medium We find that ethylene carbonate and vinylene carbonate improve electrochemical behaviour while toluene and tetrahydrofuran are less promising We also present insights into the electrode passivation caused by these diluents in an ionic liquid electrolyte during lithium cycling We observe that during lithium cycling those electrolytes with carbonate based diluents are the most able to utilise their previously repotted improved lithium ion diffusivites Conversely tetrahydrofuran the most promising diluent of those studied in terms of its known ability to increase lithium ion diffusivity is found not to be as advantageous as a diluent It appears that the poor electrochemical interfacial properties of the tetrahydrofun an electrolyte prevented the realisation of the benefits of the high solution lithium ion diffusivity Crown Copyright (C) 2010 Published by Elsevier Ltd All rights reserved