Electrochemical impedance spectroscopy: Understanding the role of the reference electrode

• Published in: Electrochemistry communications Vol. 34; pp. 208 - 210
• Main Authors: GOMEZ-CAMER, Juan Luis, NOVAK, Petr
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.09.2013; Amsterdam Elsevier; New York, NY
• Subjects: Alloys; Applied sciences; Bismuth; Chemistry; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Electrochemical impedance spectroscopy; Electrochemistry; Electrodes: preparations and properties; Exact sciences and technology; General and physical chemistry; Lithium batteries; Other electrodes; Reference electrode; Bismuth; Lithium batteries; Reference electrode; Alloys; Electrochemical impedance spectroscopy; Stability; Polarizability; Secondary cell; Lithium battery; Lithiation; Bismuth base alloys; Metalation; Lithium alloy
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2013.06.016

Bismuth based alloys with different lithium content have been synthesized by in situ electrochemical lithiation. The stability of potential of the alloys with time has been studied, showing stable potential during a period of at least 3weeks. The alloy with higher lithium content is the less polarizable, with exchange current density over 20 times higher than Li. The LixBi alloys have been implemented as reference electrode (RE) for three-electrode electrochemical impedance spectroscopy (EIS) in lithium-ion batteries and compared to Li. These alloys are proposed here as alternative to Li due to their stability and potentials positive to the solid electrolyte interphase (SEI) formation. The reaction overpotential of the RE material has been found to be a key parameter to take into account when measuring EIS with three-electrode setup. •Li-Bi is proposed as a reference electrode with a stable potential.•The Li-Bi reference electrode exhibits a potential positive to bulk SEI formation.•The Li-Bi reference electrode is suited to electrochemical impedance spectroscopy.•The Li-Bi reference electrode outperforms the lithium metal reference electrode.•The two-phase (electro)chemistry of Li-Bi is decisive for better performance.