A composite electrolyte
based on a garnet electrolyte (LLZO) and
polyester-based co-polymer (80:20 ε-caprolactone (CL)-trimethylene
carbonate, PCL-PTMC with LiTFSI salt) is prepared. Integrating the
merits of both ceramic and co-polymer electrolytes is expected to
address the poor ionic conductivity and high interfacial resistance
in solid-state lithium-ion batteries. The composite electrolyte with
80 wt % LLZO and 20 wt % polymer (PCL-PTMC and lithium bis(trifluoromethanesulfonyl)imide
(LiTFSI) at 72:28 wt %) exhibited a Li-ion conductivity of 1.31 ×
10–4 S/cm and a transference number (t
Li+
) of 0.84 at 60 °C, notably higher
than those of the pristine PCL-PTMC electrolyte. The prepared composite
electrolyte also exhibited an electrochemical stability of up to 5.4
V vs Li+/Li. The interface between the composite electrolyte
and a LiFePO4 (LFP) cathode was also improved by direct
incorporation of the polymer electrolyte as a binder in the cathode
coating. A Li/composite electrolyte/LFP solid-state cell provided
a discharge capacity of ca. 140 mAh/g and suitable cycling stability
at 55 °C after 40 cycles. This study clearly suggests that this
type of amorphous polyester-based polymers can be applied in polymer-in-ceramic
composite electrolytes for the realization of advanced all-solid-state
lithium-ion batteries.
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.
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.
Abstract: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) 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%.
OPEN ACCESSPolymers 2015, 7 267
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