High-surface-area tofu based activated porous carbon for electrical double-layer capacitors

Plasticised chitosan: Dextran polymer blend electrolyte for energy harvesting application: Tuning the ion transport and EDLC charge storage capacity through TiO2 dispersion

This study investigates the performance of biopolymer electrolytes based on chitosan and dextran for energy storage applications. The optimization of ion transport and performance of electric double-layer capacitors EDCL using these electrolytes, incorporating different concentrations of glycerol as a plasticizer and TiO2 as nanoparticles, is explored. Impedance measurements indicate a notable reduction in charge transfer resistance with the addition of TiO2. DC conductivity estimates from AC spectra plateau regions reach up to 5.6 × 10-4 S/cm. The electric bulk resistance Rb obtained from the Nyquist plots exhibits a substantial decrease with increasing plasticizer concentration, further enhanced by the addition of the nanoparticles. Specifically, Rb decreases from ∼20 kΩ to 287 Ω when glycerol concentration increases from 10 % to 40 % and further drops to 30 Ω with the introduction of TiO2. Specific capacitance obtained from cyclic voltammetry shows a notable increase as the scan rate decreases, indicating improved efficiency and stability of ion transport. The TiO2-enriched EDCL achieves 12.3 F/g specific capacitance at 20 mV/s scan rate, with high ion conductivity and extended electrochemical stability. These results suggest the great potential of plasticizer and TiO2 with biopolymers in improving the performance of energy storage systems.

High-performance nanostructured bio-based carbon electrodes for energy storage applications

Polyacrylonitrile (PAN)-based carbon precursor is a well-established and researched material for electrodes in energy storage applications due to its good physical properties and excellent electrochemical performance. However, in the fight of preserving the environment and pioneering renewable energy sources, environmentally sustainable carbon precursors with superior electrochemical performance are needed. Therefore, bio-based materials are excellent candidates to replace PAN as a carbon precursor. Depending on the design requirement (e.g. carbon morphology, doping level, specific surface area, pore size and volume, and electrochemical performance), the appropriate selection of carbon precursors can be made from a variety of biomass and biowaste materials. This review provides a summary and discussion on the preparation and characterization of the emerging and recent bio-based carbon precursors that can be used as electrodes in energy storage applications. The review is outlined based on the morphology of nanostructures and the precursor's type. Furthermore, the review discusses and summarizes the excellent electrochemical performance of these recent carbon precursors in storage energy applications. Finally, a summary and outlook are also given. All this together portrays the promising role of bio-based carbon electrodes in energy storage applications.

A Polymer Blend Electrolyte Based on CS with Enhanced Ion Transport and Electrochemical Properties for Electrical Double Layer Capacitor Applications

The fabrication of energy storage EDLC in this work is achieved with the implementation of a conducting chitosan–methylcellulose–NH₄NO₃–glycerol polymer electrolyte system. The simple solution cast method has been used to prepare the electrolyte. The impedance of the samples was fitted with equivalent circuits to design the circuit diagram. The parameters associated with ion transport are well studied at various plasticizer concentrations. The FTIR investigation has been done on the films to detect the interaction that occurs among plasticizer and polymer electrolyte. To get more insights into ion transport parameters, the FTIR was deconvoluted. The transport properties achieved from both impedance and FTIR are discussed in detail. It was discovered that the transport parameter findings are in good agreement with both impedance and FTIR studies. A sample with high transport properties was characterized for ion dominancy and stability through the TNM and LSV investigations. The dominancy of ions in the electrolyte verified as the t_ion of the electrolyte is established to be 0.933 whereas it is potentially stable up to 1.87 V. The rechargeability of the EDLC is steady up to 500 cycles. The internal resistance, energy density, and power density of the EDLC at the 1st cycle are 53 ohms, 6.97 Wh/kg, and 1941 W/kg, respectively.

Nofal M, San S, Abdulwahid RT, Raza Saeed S, Brza MA, Kadir MFZ, Mohammed SJ, Al-Zangana S. From Cellulose, Shrimp and Crab Shells to Energy Storage EDLC Cells: The Study of Structural and Electrochemical Properties of Proton Conducting Chitosan-Based Biopolymer Blend Electrolytes

In this study, solid polymer blend electrolytes (SPBEs) based on chitosan (CS) and methylcellulose (MC) incorporated with different concentrations of ammonium fluoride (NH₄F) salt were synthesized using a solution cast technique. Both Fourier transformation infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results confirmed a strong interaction and dispersion of the amorphous region within the CS:MC system in the presence of NH₄F. To gain better insights into the electrical properties of the samples, the results of electrochemical impedance spectroscopy (EIS) were analyzed by electrical equivalent circuit (EEC) modeling. The highest conductivity of 2.96 × 10⁻³ S cm⁻¹ was recorded for the sample incorporated with 40 wt.% of NH₄F. Through transference number measurement (TNM) analysis, the fraction of ions was specified. The electrochemical stability of the electrolyte sample was found to be up to 2.3 V via the linear sweep voltammetry (LSV) study. The value of specific capacitance was determined to be around 58.3 F/g. The stability test showed that the electrical double layer capacitor (EDLC) system can be recharged and discharged for up to 100 cycles with an average specific capacitance of 64.1 F/g. The synthesized EDLC cell was found to exhibit high efficiency (90%). In the 1st cycle, the values of internal resistance, energy density and power density of the EDLC cell were determined to be 65 Ω, 9.3 Wh/kg and 1282 W/kg, respectively.

Electrochemical Characteristics of Glycerolized PEO-Based Polymer Electrolytes

In this article, poly(ethylene oxide)-based polymer electrolyte films doped with ammonium iodide (NH4I) and plasticized with glycerol were provided by a solution casting method. In the unplasticized system, the maximum ionic conductivity of 3.96 × 10-5 S cm-1 was achieved by the electrolyte comprised of 70 wt. % PEO:30 wt. % NH4I. The conductivity was further enhanced up to (1.77×10-4 S cm-1) for the plasticized system when 10 wt. % glycerol was added to the highest conducting unplasticized one at ambient temperature. The films were characterized by various techniques to evaluate their electrochemical performance. The results of impedance spectroscopy revealed that bulk resistance (Rb) considerably decreased for the highest plasticized polymer electrolyte. The dielectric properties and electric modulus parameters were studied in detail. The LSV analysis verified that the plasticized system can be used in energy storage devices with electrochemical stability up to 1.09 V and the TNM data elucidated that the ions were the main charge carrier. The values of the ion transference number (tion) and electron transfer number (tel) were calculated. The nonappearance of any redox peaks in the cyclic voltammograms indicated that the chemical reaction had not occurred at the electrode/electrolyte interface.

Electrochemical performance of antimony/chlorine-incorporated nickel foam

In this paper, an Sb/Cl-incorporated nickel foam (NF) electrode material was grown on acid-pretreated NF by one-step chemical vapor deposition using SbCl₃ as the Sb source.

Facile synthesis of an all-in-one graphene nanosheets@nickel electrode for high-power performance supercapacitor application

We report a facile and novel approach for the fabrication of all-in-one supercapacitor electrodes by in situ electrochemical exfoliation of flexible graphite paper (FGP) on a nickel collector. The binder-free three dimensional (3D) graphene nanosheets@Ni (GNSs@Ni) supercapacitor electrodes exhibit a high specific capacitance of 196.4 F g⁻¹ and 36.2 mF cm⁻², respectively, at a scan rate of 50 mV s⁻¹. Even at the high scan rate of 2500 mV s⁻¹ the specific capacitance of the capacitor still shows a retention of 85.6% (168 F g⁻¹, 31 mF cm⁻²). Meanwhile, the as-prepared electrode offers excellent cycling performance with 91.5% capacitance retention after 100 000 charging–discharging cycles even at the high current density of 11 A g⁻¹. Such high rate capability, specific capacitance and exceptional cycling ability of the GNSs@Ni electrode are attributed to the all-in-one architecture which provides unique properties including high electrical conductivity, large specific surface area and excellent electrochemical stability. We anticipate that these results will shed light on new strategies to synthesize high-performance hybrid nanoarchitectures electrodes using the prepared graphene nanosheets as the support, which offers great potential in energy storage devices and electrochemical catalysis applications.

GNSs@Ni electrode has a high current density, and the C_m and C_s are estimated to be 196.4 F g⁻¹ and 36.2 mF cm⁻².

Design of an Extended Experiment with Electrical Double Layer Capacitors: Electrochemical Energy Storage Devices in Green Chemistry

An extended undergraduate experiment involving electrochemical energy storage devices and green energy is described herein. This experiment allows for curriculum design of specific training modules in the field of green chemistry. Through the study of electrical double layer capacitors, students learned to assemble an electrical double layer capacitor and perform electrochemical measurements (cyclic voltammetry and galvanostatic charge-discharge) to evaluate the effect of various electrolytes. In addition, students powered a diode with the electrical double layer capacitors. We use the laboratory module to successfully connect electrochemistry with green chemistry through the study of a real-world application. In addition, a green chemistry case study was introduced to the laboratory curriculum. During the experiment, students acquired fundamental experience in electrochemistry and gained analysis skills, critical thinking, and scientific literacy. The results of this work can be used as a case study on green chemical education that considers the students’ awareness of renewable and clean energy fields.

Reduced graphene oxide-mediated synthesis of Mn3O4 nanomaterials for an asymmetric supercapacitor cell

Herein, Mn₃O₄/reduced graphene oxide composites are prepared via a facile solution-phase method for supercapacitor application. Transmission electron microscopy results reveal the uniform distribution of Mn₃O₄ nanoparticles on graphene layers. The morphology of the Mn₃O₄ nanomaterial is changed by introducing the reduced graphene oxide during the preparation process. An asymmetric supercapacitor cell based on the Mn₃O₄/reduced graphene oxide composite with the weight ratio of 1 : 1 exhibits relatively superior charge storage properties with higher specific capacitance and larger energy density compared with those of pure reduced graphene oxide or Mn₃O₄. More importantly, the long-term stability of the composite with more than 90.3% capacitance retention after 10 000 cycles can ensure that the product is widely applied in energy storage devices.

The existence presence of rGO can affect the morphology of an Mn₃O₄/rGO composite, and the asymmetric supercapacitor cell created with this composite exhibits good capacitive performance.