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Updated: Jul 3, 2026

In Situ Lithiated Reference Electrode: Four Electrode Design for In-operando Impedance Spectroscopy
Published on: September 12, 2018
Insights into the potentiometric response behaviour vs. Li+ of LiFePO4 thin films in aqueous medium
F Sauvage1, J-M Tarascon, E Baudrin
1Laboratoire de Réactivité et Chimie des Solides, UMR CNRS 6007, Université de Picardie Jules Verne, 33 rue St. Leu, 80039 Amiens Cedex, France.
Abstract:
The potentiometric response of PLD-made LiFePO(4) thin films versus Li(+) ions in aqueous solutions has been investigated, and a sensitivity of 54 mV dec(-1) has been observed in a Li(+) concentration range of 1-10(-4) M. Physical and electrochemical measurements of electrodes aged in aqueous medium show a slight surface oxidation with formation of heterosite-FePO(4) that we show to be responsible for the stable potential response measured. Cyclic voltamperometry measurements operated in different Li(+) concentration clearly highlight the key relation between the material lithium ion insertion/de-insertion capability and its potentiometric sensing response implying a faradaic-governed sensing mechanism. Based on such a finding, selection criteria (enlisting among others the potential of the redox couple, the nature of the insertion process) are herein underlined in the search for new sensitive materials.
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