Electrochimica Acta 45 (2000) 3877 – 3883 Electrochemical characterization of polyaniline – molybdenum trisulfide electrode in non-aqueous media Florence Fusalba, Daniel Be ´langer * De ´partement de Chimie, UQAM, Case Postale 8888 Succursale Centre -Ville, Montreal, Que ´bec, Canada H3C 3P8 Received 27 July 1999; received in revised form 8 November 1999 Abstract Polyaniline (PANI) – molybdenum trisulfide (MoS 3 ) electrode, prepared by a multi-step procedure, and polyaniline electrode were characterized in non-aqueous electrolyte (0.5 M LiClO 4 /acetonitrile) by cyclic voltammetry, electro- chemical impedance spectroscopy and the electrochemical quartz crystal microbalance (EQCM). The voltammetric charge decreased slightly (20%) upon incorporation of MoS 3 in the PANI film electrode. The normalized low frequency capacitance defined as the low frequency capacitance/voltammetric charge ratio is identical for both PANI and PANI–MoS 3 electrodes suggesting that MoS 3 does not contribute to the capacitance measured. The EQCM data is consistent with mixed transport of anions and cations. Upon oxidation in 0.5 M LiClO 4 /acetonitrile, a mass change of 43 g/mol is observed for PANI–MoS 3 and this suggests that solvent is also involved in addition to ClO 4 - ingress and Li + expulsion. © 2000 Elsevier Science Ltd. All rights reserved. Keywords: Polyaniline; Conducting polymers; Molybdenum trisulfide; Electrochemical quartz crystal microbalance; Composite www.elsevier.nl/locate/electacta 1. Introduction Research on active electrode materials for recharge- able lithium batteries is extremely active at the present [1]. Both anode (e.g. carbon-based materials) and cathode materials are being investigated by several re- search groups worldwide. For the latter, one-dimen- sional transition metal chalcogenides, layered metal oxides and chalcogenides and three-dimensional transi- tion metal oxides have been prepared by various routes and systematically investigated [1,2]. On the other hand, conducting polymers such as polyacetylene, polypyrrole, polyaniline (PANI) and polythiophene [3] have been proposed as active electrode materials for lithium batteries but much less work has been per- formed on these materials relative to the inorganic materials mentioned above. More recently, conducting polymer-based composites with organic sulfide [4–6], transition metal oxides [7– 10] and transition metal sulfide [11,12] were prepared with the aim of improving the charge capacity and the electronic conductivity of the resulting electrode mate- rial. These molecular composites were prepared by chemical polymerization of the conducting polymer in- side an inorganic host [8–10] and by the coelectrodepo- sition of a conducting polymer such as polypyrrole with a transition metal sulfide, ex. molybdenum trisulfide (MoS 3 ) [12]. However, we have recently shown that PANI–MoS 3 cannot be prepared electrochemically in one step and a multistep procedure was developed for its preparation [11]. It involved the electrochemical polymerization of PANI followed by the chemical for- mation of MoS 3 within the porous PANI matrix. In this paper, we report the electrochemical charac- terization of PANI – MoS 3 composite in non-aqueous electrolyte by cyclic voltammetry, electrochemical impedance spectroscopy and electrochemical quartz * Corresponding author. Fax: +1-514-987-4054. E-mail address: belanger.daniel@uqam.ca (D. Be ´langer). 0013-4686/00/$ - see front matter © 2000 Elsevier Science Ltd. All rights reserved. PII:S0013-4686(00)00454-0