Open AccessSimple Way of Making Free-Standing Battery Electrodes and their Use in Enabling Half-Cell Impedance Measurements via μ-Reference Electrode
Author(s) -
Robert Morasch,
Bharatkumar Suthar,
Hubert A. Gasteiger
Publication year - 2020
Publication title -
journal of the electrochemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.258
H-Index - 271
eISSN - 1945-7111
pISSN - 0013-4651
DOI - 10.1149/1945-7111/ab9b93
Subject(s) - electrode , reference electrode , palladium hydrogen electrode , materials science , electrical impedance , battery (electricity) , working electrode , auxiliary electrode , dielectric spectroscopy , chemically modified electrode , quinhydrone electrode , analytical chemistry (journal) , optoelectronics , electrochemistry , chemistry , electrical engineering , electrolyte , power (physics) , physics , quantum mechanics , chromatography , engineering
Free-standing electrodes can be useful for a plethora of diagnostic measurements, as they allow transmissive measurements, stacking of electrodes, and/or measurements where the current collector would be disturbing the signal. Another advantage displayed in this publication is their use in Li-ion battery half-cells to decrease and stabilize the impedance of the counter electrode that is usually made of metallic lithium, allowing to conduct electrochemical impedance spectroscopy of a battery-type working electrode via μ -reference electrode which would otherwise show artefacts over a wide range of frequencies. Using measurements on an equivalent circuit mimicking a Li-ion battery half-cell with a μ -reference electrode we show how such artefacts arise from the large resistance in the μ -reference electrode and the imbalance in working and counter electrode resistance. We also show how the use of a free-standing graphite electrode attached to the Li-metal counter electrode (Li/FSG) reduces the counter electrode resistance and allows an artefact-free impedance measurement of the working electrode via a μ -reference electrode. Finally, we show the stability of the Li/FSG electrode and compare it to a Li-metal electrode.