scholarly journals Transport of Protons and Capacitive Properties of the Nylon/Porphyrin/Graphene Oxide Coating

2017 ◽  
Author(s):  
César A. García-Pérez ◽  
Carmina Menchaca-Campos ◽  
Miguel A. García-Sánchez ◽  
Ociel Rodríguez-Pérez ◽  
Jorge Uruchurtu
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
Composite Films ◽  
Oxide Coating ◽  
Film Coating ◽  
Bipolar Plates ◽  
Transfer Product ◽  
Low Frequencies ◽  
Capacitive Properties ◽  
Acid Environment

Electrochemical impedance (EI) measurements were performed to evaluate the nylon 66/-tetra-(para-aminophenyl) porphyrin (H2T(p-NH2)PP)/graphene oxide (GO) film coating on stainless steel and compared to the nylon/H2T(p-NH2)PP and nylon/GO film samples using 1M H2SO4 as electrolyte. The nylon/H2T(p-NH2)PP and nylon/GO composite films showed high electrochemical impedance in the order of 109 ohm-cm2 and a system controlled by mass transfer, product of a diffusion process at low frequencies with a resistance up to 5 orders of magnitude, indicating the diffusion of protons through the coating and a decrease in the metal dissolution. Otherwise, the nylon/H2T(p-NH2)PP/GO film compound evaluated show good ionic conductivity and electrochemical stability in the acid environment, acting porphyrin as a catalyst to the passage of protons through the film, reducing its electrochemical impedance up to 7 orders of magnitude with respect to the compounds nylon/H2T(p-NH2)PP and nylon/GO. Likewise, good capacitance values are also shown by modifying the concentrations of porphyrin and GO reinforcing materials. These properties are important for technological applications, such as anticorrosion coating for bipolar plates or membrane in a fuel cell type PEM, super-capacitors, etc.

Nano cellulose fibers and graphene oxide coating on polyolefin separator with uniform Li+ transportation channels for long-life and high-safety Li metal battery

2020 ◽  
pp. 1-25
Author(s):  
Dongmei Dai ◽  
Yixuan Chen ◽  
Boran Chen ◽  
Jinxu Qiu ◽  
Bao Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
Coating Layer ◽  
Cellulose Fiber ◽  
Oxide Coating ◽  
Thermal Shrinkage ◽  
Retention Capacity ◽  
Nano Cellulose ◽  
Long Life ◽  
Lithium Dendrite

Abstract Lithium anode could greatly increase the energy density of the cell, but inevitable lithium dendrites hinder its application. A powerful coating layer can effectively suppress the growth of dendrite by promoting a fast and uniform Li+ flux. Here a polyolefin separator coated with a layer of nano cellulose fiber (NCF) and graphene oxide (GO) is designed to restrain the growth of Li-dendrite and accommodate thermal shrinkage resistance. The results of electrochemical impedance spectroscopy showed that the NCF/GO coating with a mass ratio of 3:5 showed the highest value of ionic conductivity. The Li/separator/Li symmetrical battery with NCF/GO coated separator can work for 65 hours during continuous charging before the voltage dropping down to zero, which is about 40% longer than the battery with bare polyolefin separator. In addition, the NCF/GO coating layer can also increase the retention capacity ratio of a cell by more than 10% in the 100 charge/discharge cycles. In this paper, the as-prepared NCF/GO coating separator provides a reference for designing a long-life and safety battery with Li-anode by effectively inhibiting the lithium dendrite.

Co-electrodeposition of MnO2/graphene oxide coating on carbon paper from phosphate buffer and the capacitive properties

2013 ◽  
Vol 18 (2) ◽  
pp. 553-559 ◽  
Author(s):  
Hua Zhao ◽  
Feifei Liu ◽  
Gaoyi Han ◽  
Zhaoyang Liu ◽  
Bin Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phosphate Buffer ◽  
Oxide Coating ◽  
Carbon Paper ◽  
Capacitive Properties

scholarly journals Capacitive properties of polypyrrole/activated carbon composite

2014 ◽  
Vol 68 (6) ◽  
pp. 709-719 ◽  
Author(s):  
Aleksandra Porjazoska-Kujundziski ◽  
Dragica Chamovska ◽  
Toma Grchev
Keyword(s):  
Activated Carbon ◽  
Electrochemical Impedance ◽  
Composite Films ◽  
Volume Resistivity ◽  
Impedance Analysis ◽  
Carbon Composite ◽  
Homogeneous Distribution ◽  
Dispersed Particles ◽  
Capacitive Properties ◽  
Electrode Cell

Electrochemical synthesis of polypyrrole (PPy) and polypyrrole / activated carbon (PPy / AC) - composite films, with a thickness between 0.5 and 15 ?m were performed in a three electrode cell containing 0.1 mol dm-3 Py, 0.5 mol dm-3 NaClO4 dissolved in ACN, and dispersed particles of AC (30 g dm-3). Electrochemical characterization of PPy and PPy / AC composites was performed using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. The linear dependences of the capacitance (qC), redox capacitance (qred), and limiting capacitance (CL) of PPy and PPy / AC - composite films on their thickness (L), obtained by electrochemical and impedance analysis, indicate a nearly homogeneous distribution of the incorporated AC particles in the composite films (correlation coefficient between 0.991 and 0.998). The significant enhancement of qC, qred, and CL, was observed for composite films (for ?40 ? 5%) in respect to that of the ?pure? PPy. The decreased values of a volume resistivity in the reduced state of the composite film, ? = 1.3 ? 106 ? cm (for L = 7.5 ?m), for two orders of magnitude, compared to that of PPy - film with the same thickness, ? ? 108 ? cm, was also noticed.

scholarly journals Hydrophobic Modification of Graphene Oxide and Its Effect on the Corrosion Resistance of Silicone-Modified Epoxy Resin

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 89
Author(s):  
Wei Yuan ◽  
Qian Hu ◽  
Jiao Zhang ◽  
Feng Huang ◽  
Jing Liu
Keyword(s):  
Contact Angle ◽  
Corrosion Resistance ◽  
Graphene Oxide ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
X Ray ◽  
Modified Graphene Oxide ◽  
Modified Epoxy

This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2.

scholarly journals High-Performance Graphene Coating on Titanium Bipolar Plates in Fuel Cells via Cathodic Electrophoretic Deposition

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 437
Author(s):  
Yi Liu ◽  
Luofu Min ◽  
Wen Zhang ◽  
Yuxin Wang
Keyword(s):  
Graphene Oxide ◽  
Fuel Cells ◽  
Electrophoretic Deposition ◽  
High Performance ◽  
Proton Exchange Membrane ◽  
Corrosion Current ◽  
Proton Exchange ◽  
Bipolar Plates ◽  
Modified Graphene Oxide ◽  
Bare Titanium

In this article, we proposed a facile method to electrophoretically deposit a highly conductive and corrosion-resistant graphene layer on metal bipolar plates (BPs) while avoiding the oxidation of the metal substrate during the electrophoretic deposition (EPD). p-Phenylenediamine (PPD) was first grafted onto negatively charged graphene oxide (GO) to obtain modified graphene oxide (MGO) while bearing positive charges. Then, MGO dispersed in ethanol was coated on titanium plates via cathodic EPD under a constant voltage, followed by reducing the deposited MGO with H2 at 400 °C, gaining a titanium plate coated with reduced MGO (RMGO@Ti). Under the simulated environment of proton exchange membrane fuel cells (PEMFCs), RMGO@Ti presents a corrosion current of < 10−6 A·cm−2, approximately two orders of magnitude lower than that of bare titanium. Furthermore, the interfacial contact resistance (ICR) of RMGO@Ti is as low as 4 mΩ·cm2, which is about one-thirtieth that of bare titanium. Therefore, RMGO@Ti appears very promising for use as BP in PEMFCs.

scholarly journals A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 594 ◽  
Author(s):  
Mara Serrapede ◽  
Marco Fontana ◽  
Arnaud Gigot ◽  
Marco Armandi ◽  
Glenda Biasotto ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Chemical Reduction ◽  
Low Cost ◽  
Xps Analysis ◽  
3D Scaffold ◽  
Energy Storage Devices ◽  
Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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