Performance Of Solid-state Supercapacitors Research Articles

Zwitterion-dissociated polyoxometalate electrolytes for solid-state supercapacitors

Releasing cations from highly negatively charged polyoxometalates (POMs) is never an easy task. Herein, by using a zwitterion (1-sulfopropyl-3-methylimidazolium salt, MIMPS) to dissociate POMs, the proton conductivity of POM electrolytes was enhanced and the capacitive performance of solid-state supercapacitors (SCs) based on polyaniline was further improved. MIMPS can promote the dissolution and dissociation of POMs in polymer solutions, releasing more mobile protons, which is conducive to rapid proton transport. The MIMPS-modified SCs have higher capacitive performance, with an areal capacitance of 13 F·cm⁻² at a current density of 0.5 mA·cm⁻², compared to SCs without MIMPS (6.4 F·cm⁻²). In addition, the MIMPS-modified SCs have lower interfacial impedance, indicating that MIMPS can improve the proton conductivity and interfacial conduction. This work provides a new strategy for improving the overall performance of SCs by optimizing POM-based electrolytes with a zwitterion.

High-Performance MnO2 Nanowire/MoS2 Nanosheet Composite for a Symmetrical Solid-State Supercapacitor.

To improve the production rate of MoS2 nanosheets as an excellent supercapacitor (SC) material and enhance the performance of the MoS2-based solid-state SC, a liquid phase exfoliation method is used to prepare MoS2 nanosheets on a large scale. Then, the MnO2 nanowire sample is synthesized by a one-step hydrothermal method to make a composite with the as-synthesized MoS2 nanosheets to achieve a better performance of the solid-state SC. The interaction between the MoS2 nanosheets and MnO2 nanowires produces a synergistic effect, resulting in a decent energy storage performance. For practical applications, all-solid-state SC devices are fabricated with different molar ratios of MoS2 nanosheets and MnO2 nanowires. From the experimental results, it can be seen that the synthesized nanocomposite with a 1:4 M ratio of MoS2 nanosheets and MnO2 nanowires exhibits a high Brunauer–Emmett–Teller surface area (∼118 m2/g), optimum pore size distribution, a specific capacitance value of 212 F/g at 0.8 A/g, an energy density of 29.5 W h/kg, and a power density of 1316 W/kg. Besides, cyclic charging–discharging and retention tests manifest significant cycling stability with 84.1% capacitive retention after completing 5000 rapid charge–discharge cycles. It is believed that this unique, symmetric, lightweight, solid-state SC device may help accomplish a scalable approach toward powering forthcoming portable energy storage applications.

Highly efficient textile supercapacitors made with face masks waste and thermoelectric Ca3Co4O9-δ oxide

We studied the electrochemical performance of solid state supercapacitors (SCs) made with surgical face mask (FM) waste and blister packs recycled from paracetamol packaging. The Ca3Co4O9-δ (CaCo) oxide was also deposited on the SC electrodes to store charge by redox reactions. The CaCo microparticles had a plate-like morphology and had sizes in the range of 1–4 µm. They also presented a monoclinic phase according to the analysis by the X-ray diffraction. The electrochemical characterization of the face mask-based SCs was carried out and found maximum capacitance/energy density values of 1706.2 F g−1/208.4 Wh kg−1 and 816.8 F g−1/99.7 Wh kg−1 for the SCs made with and without CaCo, respectively. Thus, incorporating the CaCo into the SCs improved the energy density and capacitance by ≈108%. The best device made with CaCo also presented a moderate capacitance retention of 82.1% after 1500 cycles of charge/discharge and long discharge times of at least 10 h (at a maximum output voltage of 0.54 V). Additionally, the devices were subjected to pressing conditions by putting on them weights of 0.1–0.5 Kg and their capacitance retention was only reduced by 0.7–1.5%. The analysis by XPS, Absorbance and Raman measurements pointed out that the SCs made with CaCo presented extra redox species of Co2+/Co3+ and oxygen vacancies on their electrodes; therefore, they could store charge by redox reactions. Hence, the results presented here revealed that highly efficient SCs are possible to make from medical waste and this could help to decrease the environmental contamination by plastic residuals.

Proton-Conducting Polyoxometalates as Redox Electrolytes Synergistically Boosting the Performance of Self-Healing Solid-State Supercapacitors with Polyaniline

Energy storage devices with high volumetric and gravimetric capacitance are in urgent demand due to the booming market of portable and wearable electronics. Using redox-active molecules as electrol...

Effect of gel polymer electrolyte based on polyvinyl alcohol/polyethylene oxide blend and sodium salts on the performance of solid-state supercapacitor

In this work, the effect of gel polymer electrolytes (GPE) containing polyvinyl alcohol/polyethylene oxide (90/10, wt%) blend and different contents of sodium salt mixture (sodium acetate \((\hbox {CH}_{3}{\mathrm{COONa)}}\)/sodium sulphate \(\hbox {(Na}_{2}\hbox {SO}_{4}) = 50/50~\hbox {wt}\%\)) on the performance of solid-state supercapacitor was investigated. The active electrode of the solid-state supercapacitor was made from graphene nanoplatelets and carbon black. The results indicate that the sodium salt mixtures were easily mixed in polymer blend gel to make excellent GPE with large concentration of ionic liquid. At the sodium salt mixture content of 30%, the solid-state supercapacitor showed the best performance of electrode-specific capacitance of \(93.768 \hbox { F g}^{-1}\) at current density of \(1\hbox { A g}^{-1}\), energy density of \(3.25\hbox { Wh kg}^{-1}\) and power density of \(586.166 \hbox { W kg}^{-1}\). These results highly recommend the good potential of GPE for developing solid-state supercapacitor in the future.

Effect of carbon black addition on thermal stability and capacitive performances of supercapacitors

In this study, we propose a simple way to improve thermal stability of solid-state supercapacitors (SCs) by adding carbon black (CB) into reduced graphene oxide (rGO) electrodes. The CB used as a heat-resistant additive contributes to stable operation of the rGO-CB SC even after 1000 charge/discharge cycles at 90 °C. In the case of the rGO SC without CB, it fails after the 166th cycles at 90 °C. Compared with the rGO SC, the rGO-CB SC exhibits the decrease in internal resistance from 42 to 18 Ω and the increase in specific capacitance from 115 to 160 F/g. Moreover, the rGO-CB SC shows a smaller variation in specific capacitance (12%) than that of rGO SC (30%) as the temperature increases from 30 to 90 °C. The observation reveals that the addition of CB being a heat-resistant additive helps improve performance of thermal stable SCs.

Performance of solid state supercapacitors based on polymer electrolytes containing different ionic liquids

Abstract Four Ionic Liquid based Polymer Electrolytes (IL-b-PE) were prepared by blending a Polymeric Ionic Liquid, Poly(diallyldimethylammonium) bis(trifluoromethanesulfonyl)imide (PILTFSI), with four different ionic liquids: 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) (IL-b-PE1), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (PYR14FSI) (IL-b-PE2), 1-(2-hydroxy ethyl)-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (HEMimTFSI) (IL-b-PE3), and 1-Butyl-1-methylpyrrolidinium dicyanamide, (PYR14DCA) (IL-b-PE4). Physicochemical properties of IL-b-PE such as ionic conductivity, thermal and electrochemical stability were found to be dependent on the IL properties. For instance, ionic conductivity was significantly higher for IL-b-PE2 and IL-b-PE4 containing IL with small size anions (FSI and DCA) than IL-b-PE1 and IL-b-PE3 bearing IL with bigger anion (TFSI). On the other hand, wider electrochemical stability window (ESW) was found for IL-b-PE1 and IL-b-PE2 having ILs with electrochemically stable pyrrolidinium cation and FSI and TFSI anions. Solid state Supercapacitors (SCs) were assembled with activated carbon electrodes and their electrochemical performance was correlated with the polymer electrolyte properties. Best performance was obtained with SC having IL-b-PE2 that exhibited a good compromise between ionic conductivity and electrochemical window. Specific capacitance (Cam), real energy (Ereal) & real power densities (Preal) as high as 150 F g−1, 36 Wh kg−1 & 1170 W kg−1 were found at operating voltage of 3.5 V.

All Solid-State Fexible Supercapacitors Based on Titanium Dioxide@Polypyrrole Core–shell Nanowires

not Available.

Performance of solid-state supercapacitors with ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate based gel polymer electrolyte and modified MWCNT electrodes

A new ionic liquid gel polymer electrolyte based on hydrophobic ionic liquid 1-ethyl-3-methylimidazolium tris(pentafluoroethyl) trifluorophosphate (EMImFAP) entrapped in poly (vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) copolymer has been prepared for its application as an electrolyte in supercapacitor fabrication. The gel electrolyte film shows excellent thermal stability and remains stable in the same gel phase over a substantially wide temperature range from 5 to 90°C. The gel material possesses wider electrochemical window of ∼4.4V (−2.2 to 2.2V) and high ionic conductivity of ∼2×10−3Scm−1 at room temperature. The solid-state supercapacitors have been fabricated with pristine and nitric acid treated MWCNT electrodes using the new ionic liquid gel polymer electrolyte. The performance characteristics of the capacitors have been evaluated by impedance spectroscopy, cyclic voltammetry, and galvanostatic charge–discharge measurements. A substantial improvement in the specific capacitance has been found due to the acid treatment of the MWCNTs. The modified MWCNT electrodes show the maximum capacitance value of ∼76Fg−1, which corresponded to the specific energy of ∼17.2Whkg−1 and specific power of ∼18.9kWkg−1 of MWCNT with ionic liquid gel polymer electrolyte based supercapacitor cells. The supercapacitor shows good cycling performance with ∼82% capacitance retention after 10,000 charge–discharge cycles.