A lithium iron phosphate reference electrode for ionic liquid electrolytes

Johannes Wandt, Junqiao Lee, Damien W.M. Arrigan, Debbie S. Silvester
2018 Electrochemistry communications  
We report on the development of a very simple and robust reference electrode suitable for use in room temperature ionic liquids, that can be employed with planar devices. The reference electrode is based on LiFePO4 (LFP), a common cathode material in Li-ion batteries, which is air and water stable. The reference electrode can be drop-cast onto a planar electrode device in a single step. We demonstrate that very low Li + -ion concentrations (millimolar or below) are sufficient to obtain a stable
more » ... and reproducible LFP potential, thus making physical separation between the reference and working electrode unnecessary. Most importantly, the LFP potential is also entirely stable in the presence of oxygen and only shows a very small drift (less than 10 mV) in the presence of hydrogen gas, while the potential of a platinum pseudo-reference electrode is shifted more than 800 mV. This is the first time that such a stable reference electrode system for ionic liquids has been implemented in miniaturized, planar electrode devices. Keywords Reference electrode; room temperature ionic liquids; lithium iron phosphate; planar electrode devices © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/ by-nc-nd/4.0/
doi:10.1016/j.elecom.2018.07.006 fatcat:o75wgvftpbccvbsiwbevwie76y