Conducting polymers have been widely used in electrochemical sensors as receptors of the sensing signal’s analytes and transducers. Polypyrrole (PPy) conducting polymers are highlighted due to their good electrical conductive properties, ease in preparation, and flexibility of surface characteristics. The objective of this review paper is to discuss the theoretical background of the two main types of electrochemical detection: impedimetric and voltammetric analysis. It also reviews the application and results obtained from these two electrochemical detections when utilizing PPy as a based sensing material in electrochemical sensor. Finally, related aspects in electrochemical sensor construction using PPy will also be discussed. It is anticipated that this review will provide researchers, especially those without an electrochemical analysis background, with an easy-to-understand summary of the concepts and technologies used in electrochemical sensor research, particularly those interested in utilizing PPy as a based sensing material.

This work was undertaken to study the conductivity and dielectric behavior of a biopolymer electrolyte based on carboxymethyl cellulose that was synthesized from kenaf fiber. Biopolymer electrolytes comprised of various weight percentage ratios of the host polymer, ammonium acetate salt, and butyl-trimethyl ammonium bis(trifluoromethylsulfonyl)imide ionic liquid were prepared by the solution casting technique. The conductivity values were determined by impedance spectroscopy. The highest conductivity found was 2.18 × 10⁻³ S cm⁻¹ at ambient temperature for the film incorporated with 20 wt.% salt and 20 wt.% ionic liquid. In order to understand the conductivity behavior, a dielectric study was carried out. The results showed that the system obeys the Arrhenius rule and confirmed non-Debye behavior in the sample.

Polyester‐ and polycarbonate‐based polymer electrolytes have attracted great interest after displaying promising functionality for solid‐state Li batteries. In this present work, poly(ϵ‐caprolactone‐co‐trimethylene carbonate) electrolytes are further developed by the inclusion of ZrO₂ particles, prepared by an in situ sol‐gel method. SEM micrographs show that the ZrO₂ particles are uniform and 30–50 nm in size. Contrary to many studies on filler‐polymer electrolytes, the changes in ionic conductivity are less significant upon addition of zirconia filler to the polymer electrolyte, but remain at ∼10⁻⁵ S cm⁻¹ at room temperature. This can be explained by the amorphous nature of the polymer. Instead, high lithium transference numbers (0.83–0.87) were obtained. Plating/stripping tests with Li metal electrodes show long‐term cycling performance for >1000 cycles at 0.2 mA cm⁻². Promising solid‐state lithium battery cycling results at ambient temperature using the material are also shown.

After decades of development, ionic liquid gel polymer electrolytes (ILGPEs) are currently experiencing a renaissance as a promising electrolyte to be used in electrochemical devices. Their inherent tendency towards poor electrochemical properties have limited their applications and commercialization activities. Henceforth, gel polymer electrolyte (GPE) is being introduced to alleviate the abovementioned issues. In this work, the assessment of the ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF₄] in poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) to form ILGPE was done. The relationship of [BMIM][BF₄] towards the dielectric properties at different wt. % ratios and temperature was ascertained. The results indicated that [BMIM]BF₄ is able to facilitate fast conduction. Moreover, it was found that [BMIM][BF₄] could serve as an effective agent in reducing crystallinity and glass transition temperature of the polymer and thus enhanced the ionic conductivity of the samples. Notwithstanding, the ILGPE sample possessed a high thermal stability up to 300 °C and good electrochemical stability of 4.2 V which are beneficial for operation in electrochemical devices. All in all, the correlation between the ionic liquid chemistry and electrochemical performances could provide a valuable insight to rational selection and design for ILGPE electrolytes.

Polymer electrolytes based on 90 wt% of methyl methacrylate and 10 wt% of ethyl methacrylate (90MMA-co-10EMA) incorporating different weight ratios of sodium iodide were prepared using the solution casting method. The complexation between salt and copolymer host has been investigated using Fourier transform infrared spectroscopy. The ionic conductivity and thermal stability of the electrolytes were measured using impedance spectroscopy and differential scanning calorimetry, respectively. Scanning electron microscopy was used to study the morphology of the polymer electrolytes. The ionic conductivity and glass transition temperature increased up to 20 wt% of sodium iodide (5.19 × 10⁻⁶ S·cm⁻¹) and decreased with the further addition of salt concentration, because of the crosslinked effect. The morphology behavior of the highest conducting sample also showed smaller pores compared to the other concentration. The total ionic transference number proved that this system was mainly due to ions, and the electrochemical stability window was up to 2.5 V, which is suitable for a dye-sensitized solar cell application. This sample was then tested in a dye-sensitized solar cell and exhibited an efficiency of 0.62%.