Journal of Materials Chemistry A · 2013 · 154 citations · 29 references
Natural SciencesMaterials EngineeringMaterials ScienceElectrochemistryEnergy MaterialsPolymer ChemistryElectrochemical CellsElectrochemical Energy StorageElectrode MaterialsElectrode-electrolyte InterfacesIonic ConductivitySupercapacitorsCapacitanceCapacitorsComposite Electrode MaterialsElectrochemical CapacitorsElectrochemical WindowGel Polymer ElectrolytesIonic Liquid ElectrolytesVoltammetry
The authors developed a novel ionic liquid gel polymer electrolyte based on 1‑ethyl‑3‑methylimidazolium tetracyanoborate in a PVdF‑HFP matrix for use as the electrolyte in electrochemical double‑layer supercapacitors. They fabricated solid‑state EDLCs with MWCNT electrodes and the ILGPE film, compared them to cells using pure EMImTCB, and assessed performance through impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge tests. The ILGPE exhibited thermal stability up to 310 °C, a 3.8 V electrochemical window, and 9 × 10⁻³ S cm⁻¹ conductivity, while the resulting EDLCs delivered ~34.4 F g⁻¹ capacitance, 3.5 Wh kg⁻¹ energy, and 4.2 kW kg⁻¹ power, demonstrating its promise as an electrolyte.
A novel ionic liquid gel polymer electrolyte (ILGPE) based on low viscosity ionic liquid 1-ethyl-3-methylimidazolium tetracyanoborate (EMImTCB) entrapped in poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer has been prepared for its application as an electrolyte in electrochemical double layer supercapacitors. The ILGPE shows excellent thermal stability up to 310 °C, a wider electrochemical window of ∼3.8 V (vs. Ag) and a high ionic conductivity of ∼9 × 10−3 S cm−1 at room temperature. The solid-state electrochemical double layer capacitors (EDLCs) have been fabricated with MWCNT electrodes and ILGPE films. The EDLC cells have also been fabricated with pure ionic liquid EMImTCB for comparison. The performance characteristics have been evaluated by impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge studies. The ILGPE based EDLCs show comparable capacitance values (∼34.4 F g−1) and the values of the resistive parameters as compared to the pure ionic liquid based capacitor cells. The solid-state EDLC cell shows a specific energy of ∼3.5 W h kg−1 and a specific power of ∼4.2 kW kg−1 of MWCNT. The performance studies on EDLCs indicate the excellent potential of the ionic liquid EMImTCB based gel polymer films as electrolytes.
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Materials for electrochemical capacitors
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