Active Carbon Modified by Rhenium Species as a Perspective Supercapacitor Electrode

We have reported the synthesis of a new kind of composite combining a rhenium precursor and active carbon. Similarly to other refractory metals, rhenium exhibits several oxidation states that makes it an ideal candidate for redox-type energy storage materials. A simple impregnation of pretreated active carbon with ammonium perrhenate allowed to produce an electrode material with an enhanced specific capacitance. There was not any observed detrimental effect of metal species on the cycle life of the electrode. A small increase in charge transfer resistance was counter-balanced by the improved impedance in the whole examined range.

Download Full-text

Effect of Plating Solutions on Supercapacitor Characteristics of MnO2 Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.113-116.1810 ◽

2010 ◽

Vol 113-116 ◽

pp. 1810-1813

Author(s):

Fang Xiao ◽

You Long Xu

Keyword(s):

Electrode Materials ◽

Electrochemical Impedance ◽

Equivalent Circuit Model ◽

Active Surface ◽

Charge Transfer Resistance ◽

Electrochemical Impedance Spectrum ◽

Active Surface Area ◽

Cyclic Voltammograms ◽

Supercapacitor Electrode ◽

Transfer Resistance

MnO2 films were electrodeposited on the Ti substrates by galvanostatic method in various plating solutions, which was MnCl2, Mn(NO3)2, MnSO4 and Mn(CH3COO)2 solutions, respectively. On X-ray diffraction test, Crystal structures of all MnO2 films were associated to α-MnO2 of tetragonal crystal system. Scanning electron microscopy results show that morphologies of MnO2 films were clearly different. Among them, MnO2 film prepared in Mn(CH3COO)2 solution presented a lot of cracks and holes. According to electrochemical impedance spectrum analysis, this MnO2 film presents the lowest charge-transfer resistance. Additionally, electrochemical active surface areas of MnO2 films were calculated on the basis of equivalent circuit model for impedance data. The result was found that MnO2 film prepared in Mn(CH3COO)2 solution showed the biggest electrochemical active surface area, which was about 382 cm2. Cyclic voltammograms were carried out for all the samples. MnO2 film formed in Mn(CH3COO)2 solution showed the highest special capacitance of 230 F g-1. The results suggest that Mn(CH3COO)2 solution is suitable for electrodepositing MnO2 film using supercapacitor electrode materials.

Download Full-text

Synthesis of Graphene Functionalized Melamine and its Application for Supercapacitor Electrode

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.773.128 ◽

2018 ◽

Vol 773 ◽

pp. 128-132

Author(s):

Wesarach Samoechip ◽

Prasit Pattananuwat ◽

Pranut Potiyaraj

Keyword(s):

Energy Storage ◽

Nitrogen Content ◽

Reducing Agent ◽

Energy Storage Materials ◽

Supercapacitor Electrode ◽

Supercapacitor Application ◽

Capacitive Behavior ◽

Ideal Candidate ◽

Graphene Doping ◽

Doped Graphene

In this work, we describe the development of graphene as energy storage materials that are supercapacitors. Melamine is successfully used as a Nitrogen source for graphene doping by simple reflux process. The influence of reducing agent ratio is also investigated to study the degree of reducing of graphene functionalized melamine on capacitive behavior. At reducing agent/graphene ratio of 1:1, the nitrogen functional graphene can deliver the highest specific capacitance of 333.38 F/g at 10mV/sec, which is much higher than that obtained from bare graphene. The increasing of reducing agent ratio higher than 1 tends to decrease the capacitive values of graphene functionalized melamine confirming the efficiency of doped Nitrogen content on graphene. This N-doped graphene feature can be viewed as the potentially ideal candidate materials for supercapacitor application.

Download Full-text

Preparation and electrochemical characterization of PANI/MnCo2O4 nanocomposite as supercapacitor electrode material

Canadian Journal of Chemistry ◽

10.1139/cjc-2017-0423 ◽

2018 ◽

Vol 96 (5) ◽

pp. 477-483 ◽

Cited By ~ 3

Author(s):

Saeid Panahi ◽

Moosa Es’haghi

Keyword(s):

Specific Capacitance ◽

Surface Characterization ◽

Electrochemical Impedance ◽

Rate Capability ◽

Cycling Performance ◽

Charge Transfer Resistance ◽

X Ray Diffraction ◽

Supercapacitor Electrode ◽

Transfer Resistance

In this work, PANI/MnCo2O4 nanocomposite was prepared via in-situ chemical polymerization method. Materials synthesized were characterized by FTIR spectroscopy, X-ray diffraction, and scanning electron spectroscopy. In addition, surface characterization of samples such as specific surface area, pore volume, and pore size distribution was studied. Supercapacitor capability of materials was investigated in 1 mol L–1 Na2SO4 solution using cyclic voltammetry in different potential scan rates and electrochemical impedance spectroscopy (EIS). The specific capacitance of materials was calculated, and it was observed that the specific capacitance of PANI/MnCo2O4 nanocomposite was 185 F g−1, much larger than PANI. Moreover, the prepared nanocomposite exhibited better rate capability in scan rate of 100 mV s−1 with respect to PANI. The EIS experiments revealed that the nanocomposite has lower charge transfer resistance compared with pure PANI. Subsequently, it was shown that the nanocomposite cycling performance was superior to the PANI cycling performance.

Download Full-text

Electrochemically Reduced Titania Nanotube Synthesized from Glycerol-Based Electrolyte as Supercapacitor Electrode

Energies ◽

10.3390/en13112767 ◽

2020 ◽

Vol 13 (11) ◽

pp. 2767 ◽

Cited By ~ 1

Author(s):

Muhammad Muhammad Muzakir ◽

Zulkarnain Zainal ◽

Hong Ngee Lim ◽

Abdul Halim Abdullah ◽

Noor Nazihah Bahrudin ◽

...

Keyword(s):

Specific Capacitance ◽

Reduction Process ◽

High Specific Capacitance ◽

Charge Transfer Resistance ◽

Tube Diameter ◽

Titania Nanotubes ◽

Supercapacitor Electrode ◽

Transfer Resistance ◽

Self Organized ◽

Electrons And Ions

In this paper the synthesis of self-organized Titania nanotubes (TNTs) by a facile potentiostatic anodization in a glycerol-based electrolyte is reported. The optimized TNTs were subsequently reduced through a cathodic reduction process to enhance its capacitive performance. FESEM and XRD were used to characterize the morphology and crystal structure of the synthesized samples. XPS analysis confirmed the reduction of Ti4+ to Ti3+ ions in the reduced Titania nanotubes (R-TNTs). The tube diameter and separation between the tubes were greatly influenced by the applied voltage. TNTs synthesized at voltage of 30 V for 60 min exhibited 86 nm and 1.1 µm of tube diameter and length, respectively and showed high specific capacitance of 0.33 mF cm−2 at current density of 0.02 mA cm−2. After reduction at 5 V for 30 s, the specific capacitance increased by about seven times (2.28 mF cm−2) at 0.5 mA cm−2 and recorded about 86% capacitance retention after 1000 continuous cycling at 0.2 mA cm−2, as compared to TNTs, retained about 61% at 0.01 mA cm−2. The charge transfer resistance drastically reduced from 6.2 Ω for TNTs to 0.55 Ω for R-TNTs, indicating an improvement in the transfer of electrons and ions across the electrode–electrolyte interface.

Download Full-text

Synthesis of Conducting Bifunctional Polyaniline@Mn-TiO2 Nanocomposites for Supercapacitor Electrode and Visible Light Driven Photocatalysis

Catalysts ◽

10.3390/catal10050546 ◽

2020 ◽

Vol 10 (5) ◽

pp. 546 ◽

Cited By ~ 9

Author(s):

Milan Babu Poudel ◽

Changho Yu ◽

Han Joo Kim

Keyword(s):

Tio2 Nanoparticles ◽

Electrochemical Impedance ◽

Oxidative Polymerization ◽

Synergetic Effect ◽

Band Gap Energy ◽

Charge Transfer Resistance ◽

Visible Spectroscopy ◽

Supercapacitor Electrode ◽

Transfer Resistance ◽

Uv Visible

We report a polyaniline-wrapped, manganese-doped titanium oxide (PANi/Mn-TiO2) nanoparticle composite for supercapacitor electrode and photocatalytic degradation. The PANi/Mn-TiO2 nanoparticles were synthesized using a solvothermal process, followed by oxidative polymerization of aniline. The structural properties of studied materials were confirmed by XRD, FTIR, HRTEM, FESEM, and UV visible spectroscopy. The as-prepared PANi/Mn-TiO2 nanoparticles revealed admirable electrochemical performance with a specific capacitance of 635.87 F g−1 at a current density of 1 A g−1 with a notable life cycle retention of 91% after 5000 charge/discharge cycles. Furthermore, the asymmetric cell with PANi/Mn-TiO2 as a positive electrode exhibited energy density of 18.66 W h kg−1 with excellent stability. Moreover, the PANi/Mn-TiO2 had promising photocatalytic activity for methylene blue degradation. The improved performance of PANi/Mn-TiO2 nanoparticles is attributed to the well-built synergetic effect of components that lead to significant reduction of band gap energy and charge transfer resistance, as revealed by UV visible spectroscopy and electrochemical impedance spectroscopy.

Download Full-text

Research on CuxSy/CoSz/graphene supercapacitor electrode materials

Materials Express ◽

10.1166/mex.2020.1819 ◽

2020 ◽

Vol 10 (10) ◽

pp. 1725-1731

Author(s):

Xiaobo Duan ◽

Yanhong Ding ◽

Meng Yu

Keyword(s):

Hydrothermal Method ◽

Electrode Materials ◽

Retention Rate ◽

Specific Capacity ◽

Charge Transfer Resistance ◽

Diffusion Resistance ◽

Multilayer Graphene ◽

Supercapacitor Electrode ◽

Transfer Resistance ◽

Two Samples

Multilayer graphene was prepared in this study by microwave burst method. Cu9S5/CoS/graphene and CuS/CoS2/graphene composites were obtained by hydrothermal method to regulate the molecular structure and combination of Cu and Co metal sulfides on graphene substrate. Graphite oxide was doped by hydrothermal method, and then Cu9S5/CoS/graphene composite was prepared by microwave explosion method. Raman, SEM and TEM were used to characterize the self-made graphene. Results showed that the multilayer graphene had a bag-like structure which was beneficial to anchor sulfide. Three graphene-based composites were characterized by scanning electron microscopy, X-ray diffraction, energy spectrum analysis and electrochemical properties. Moreover, results showed that CuS/CoS2/graphene had the best electrochemical performance, and its specific capacity reached 324 F/g when the current density was 1 A · g–1, which was much higher than that of the other two samples. Capacity retention rate, interfacial charge transfer resistance and electrolyte diffusion resistance also have advantages.

Download Full-text

Improvement of Ti/RuO2–IrO2 Anode Lifetime and Electrocatalytical Properties by Using an Eco-Friendly Thermal Decomposition Method Using Polyvinyl Alcohol as Solvent

10.26434/chemrxiv.7991129 ◽

2019 ◽

Author(s):

Charlys Bezerra ◽

Géssica Santos ◽

Marilia Pupo ◽

Maria Gomes ◽

Ronaldo Silva ◽

...

Keyword(s):

Thermal Decomposition ◽

Polyvinyl Alcohol ◽

High Efficiency ◽

Electrochemical Impedance ◽

Pechini Method ◽

Low Cost ◽

Charge Transfer Resistance ◽

Transfer Resistance ◽

Calcination Temperatures ◽

Service Lifetime

Electrochemical oxidation processes are promising solutions for wastewater treatment due to their high efficiency, easy control and versatility. Mixed metal oxides (MMO) anodes are particularly attractive due to their low cost and specific catalytic properties. Here, we propose an innovative thermal decomposition methodology using <a>polyvinyl alcohol (PVA)</a> as a solvent to prepare Ti/RuO2–IrO2 anodes. Comparative anodes were prepared by conventional method employing a polymeric precursor solvent (Pechini method). The calcination temperatures studied were 300, 400 and 500 °C. The physical characterisation of all materials was performed by X-ray diffraction and scanning electron microscopy coupled with energy dispersive spectroscopy, while electrochemical characterisation was done by cyclic voltammetry, accelerated service lifetime and electrochemical impedance spectroscopy. Both RuO2 and IrO2 have rutile-type structures for all anodes. Rougher and more compact surfaces are formed for the anodes prepared using PVA. Amongst temperatures studied, 300 °C using PVA as solvent is the most suitable one to produce anodes with expressive increase in voltammetric charge (250%) and accelerated service lifetime (4.3 times longer) besides reducing charge-transfer resistance (8 times lower). Moreover, the electrocatalytic activity of the anodes synthesised with PVA toward the Reactive Blue 21 dye removal in chloride medium (100 % in 30 min) is higher than that prepared by Pechini method (60 min). Additionally, the removal total organic carbon point out improved mineralisation potential of PVA anodes. Finally, this study reports a novel methodology using PVA as solvent to synthesise Ti/RuO2–IrO2 anodes with improved properties that can be further extended to synthesise other MMO compositions.

Download Full-text

Control of the interfacial charge transfer resistance to improve the performance of quantum dot sensitized solar cells with highly electrocatalytic Cu-doped SnS counter electrodes

Applied Surface Science ◽

10.1016/j.apsusc.2020.145297 ◽

2020 ◽

Vol 508 ◽

pp. 145297

Author(s):

Mohammed Panthakkal Abdul Muthalif ◽

Youngson Choe

Keyword(s):

Solar Cells ◽

Charge Transfer ◽

Quantum Dot ◽

Charge Transfer Resistance ◽

Counter Electrodes ◽

Transfer Resistance ◽

Interfacial Charge Transfer ◽

Sensitized Solar Cells ◽

Interfacial Charge

Download Full-text

Electrochemical Immunosensor for the Quantification of S100B at Clinically Relevant Levels Using a Cysteamine Modified Surface

Sensors ◽

10.3390/s21061929 ◽

2021 ◽

Vol 21 (6) ◽

pp. 1929

Author(s):

Alexander Rodríguez ◽

Francisco Burgos-Flórez ◽

José D. Posada ◽

Eliana Cervera ◽

Valtencir Zucolotto ◽

...

Keyword(s):

Frequency Analysis ◽

Surface Characterization ◽

Electrochemical Impedance ◽

Limit Of Detection ◽

Neuronal Damage ◽

Charge Transfer Resistance ◽

Single Frequency ◽

Response Analysis ◽

Transfer Resistance ◽

Therapeutic Decisions

Neuronal damage secondary to traumatic brain injury (TBI) is a rapidly evolving condition, which requires therapeutic decisions based on the timely identification of clinical deterioration. Changes in S100B biomarker levels are associated with TBI severity and patient outcome. The S100B quantification is often difficult since standard immunoassays are time-consuming, costly, and require extensive expertise. A zero-length cross-linking approach on a cysteamine self-assembled monolayer (SAM) was performed to immobilize anti-S100B monoclonal antibodies onto both planar (AuEs) and interdigitated (AuIDEs) gold electrodes via carbonyl-bond. Surface characterization was performed by atomic force microscopy (AFM) and specular-reflectance FTIR for each functionalization step. Biosensor response was studied using the change in charge-transfer resistance (Rct) from electrochemical impedance spectroscopy (EIS) in potassium ferrocyanide, with [S100B] ranging 10–1000 pg/mL. A single-frequency analysis for capacitances was also performed in AuIDEs. Full factorial designs were applied to assess biosensor sensitivity, specificity, and limit-of-detection (LOD). Higher Rct values were found with increased S100B concentration in both platforms. LODs were 18 pg/mL(AuES) and 6 pg/mL(AuIDEs). AuIDEs provide a simpler manufacturing protocol, with reduced fabrication time and possibly costs, simpler electrochemical response analysis, and could be used for single-frequency analysis for monitoring capacitance changes related to S100B levels.

Download Full-text

Influence of HAP on the Morpho-Structural Properties and Corrosion Resistance of ZrO2-Based Composites for Biomedical Applications

Crystals ◽

10.3390/cryst11020202 ◽

2021 ◽

Vol 11 (2) ◽

pp. 202

Author(s):

Réka Barabás ◽

Carmen Ioana Fort ◽

Graziella Liana Turdean ◽

Liliana Bizo

Keyword(s):

Electrochemical Impedance ◽

Artificial Saliva ◽

Synergetic Effect ◽

Composite Layer ◽

Charge Transfer Resistance ◽

Processing Route ◽

Dental Alloys ◽

Metallic Electrode ◽

Transfer Resistance ◽

X Ray

In the present work, ZrO2-based composites were prepared by adding different amounts of antibacterial magnesium oxide and bioactive and biocompatible hydroxyapatite (HAP) to the inert zirconia. The composites were synthesized by the conventional ceramic processing route and morpho-structurally analyzed by X-ray powder diffraction (XRPD) and scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS). Two metallic dental alloys (i.e., Ni–Cr and Co–Cr) coated with a chitosan (Chit) membrane containing the prepared composites were exposed to aerated artificial saliva solutions of different pHs (i.e., 4.3, 5, 6) and the corrosion resistances were investigated by electrochemical impedance spectroscopy technique. The obtained results using the two investigated metallic dental alloys shown quasi-similar anticorrosive properties, having quasi-similar charge transfer resistance, when coated with different ZrO2-based composites. This behavior could be explained by the synergetic effect between the diffusion process through the Chit-composite layer and the roughness of the metallic electrode surface.

Download Full-text