Electric Double Layer at the Rutile (110) Surface. 2. Adsorption of Ions from Molecular Dynamics and X-ray Experiments

2004 ◽  
Vol 108 (32) ◽  
pp. 12061-12072 ◽  
Author(s):  
M. Předota ◽  
Z. Zhang ◽  
P. Fenter ◽  
D. J. Wesolowski ◽  
P. T. Cummings
Keyword(s):  
Molecular Dynamics ◽  
Double Layer ◽  
Electric Double Layer ◽  
X Ray

Electrochemical Properties of Supercapacitors Using Boron Nitrogen Double-Doped Carbon Nanotubes as Conductive Additive

NANO ◽  
2019 ◽  
Vol 14 (07) ◽  
pp. 1950080
Author(s):  
Hao Hu ◽  
Xiaogang Sun ◽  
Wei Chen ◽  
Jie Wang ◽  
Xu Li ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Double Layer ◽  
Specific Surface Area ◽  
Electric Double Layer ◽  
X Ray ◽  
Nitrogen Doped ◽  
Conductive Additive ◽  
Double Layer Capacitors ◽  
Boron Nitrogen

Carbon nanotubes (CNTs) were doped by ammonium borate as the sources of nitrogen and boron. Under the protection of Ar gas, boron-nitrogen doped CNTs were prepared through nitriding and boronization at high temperature. It is a conductive additive. Then, the obtained CNTs were mixed with activated carbon (AC), SP, sodium dodecyl sulfate (SDS), and cellulose fiber to prepare electrodes. With all the materials, a symmetric electric double-layer supercapacitor (EDLC) was assembled. Next, the materials and electrodes were also characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The factors, chemical connections, and specific surface area of the CNTs were analyzed by X-ray energy spectrum analysis (EDS), X-ray photoelectron spectroscopy (XPS), as well as a specific surface area and porosimetry analyzer (BET). In addition, the electrochemical performances of electric double-layer capacitors were tested with the help of cyclic voltammetry, constant-current charging and discharging, and so on. From the results, we can make a conclusion, that is, both B and N atoms were added into the CNTs and formed bonds successfully with carbon atoms mutually. Besides, the specific surface area is about 1.5 times than that of the CNT. When the charge/discharge current density reaches 50[Formula: see text]mA/g, we can find that the mass specific capacitance of the capacitor can run up to 32.19[Formula: see text]F/g. Also, we observe that the maximum power density is close to 220[Formula: see text]W/kg (700[Formula: see text]mA/g), and the energy density can arrive 9.31[Formula: see text]Wh/kg (50[Formula: see text]mA/g). Based on the impedance test, the electrodes are characterized with low impedance. After 2000 cycles, the boron-nitrogen doped double-layer capacitors maintain a capacitance retention ratio of above 95%. Its power density can still achieve 220[Formula: see text]W/kg when the energy density keeps at 3.46[Formula: see text]Wh/kg. In other words, the electrochemical performance functions of the electric double-layer capacitors are enhanced while the CNTs serve as the electrodes.

Dynamical Response of the Electric Double Layer Structure of the DEME-TFSI Ionic Liquid to Potential Changes Observed by Time-Resolved X-ray Reflectivity

2016 ◽  
Vol 230 (4) ◽  
Author(s):  
Wolfgang Voegeli ◽  
Etsuo Arakawa ◽  
Tadashi Matsushita ◽  
Osami Sakata ◽  
Yusuke Wakabayashi
Keyword(s):  
Ionic Liquid ◽  
Double Layer ◽  
Time Scale ◽  
Electric Double Layer ◽  
Structural Changes ◽  
Layer Structure ◽  
Dynamical Response ◽  
Relaxation Processes ◽  
Time Resolved ◽  
X Ray

AbstractThe interface between the N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium bis(trifluoromethanesulfonyl)imide (DEME-TFSI) ionic liquid and a gold (111) surface was investigated with time-resolved X-ray reflectivity in order to clarify the dynamics of structural changes of the electric double layer after changing the electrode potential. In the experiment, the potential was switched repeatedly between +1.5 V and −1.5 V every 2 s or every 0.3 s, while measuring the specular X-ray reflectivity. When the potential was switched every 2 s, the time dependence of the reflectivity was different from that of the accumulated charge. This indicates structural relaxation processes that occur on a slower time scale than the acummulation of the charge at the electric double layer.When the potential was switched every 0.3 s, on the other hand, the reflectivity changes followed the evolution of the charge of the electric double layer within the experimental precision, indicating that slow relaxation processes without charge transfer do not contribute significantly to structural changes at this time scale.

scholarly journals Study of the structural and electrical properties of the PVA–NH4SCN membrane for its application in electric double layer capacitors

2021 ◽  
pp. 79-86
Author(s):  
Ashwini Swaminathan ◽  
◽  
Ranjithkumar Ravi ◽  
Sakunthala Ayyasamy ◽  
Vidhya Bhojan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Double Layer ◽  
Electric Double Layer ◽  
Polymer Membranes ◽  
Electric Double Layer Capacitor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Double Layer Capacitor ◽  
Scanning Electron

The PVA–NH4SCN polymer membranes were prepared by simple solution casting technique by passing ultrasound waves during the preparation. The polymer membranes were subjected to X-ray diffraction analysis and scanning electron microscopy. The X-ray diffraction pattern confirmed the incorporation of a salt into the polymer matrix. The scanning electron microscopy images showed the morphological changes of the polymer membrane. The polymer electrolyte (designated as UPVA20) incorporated with the 20 wt.% of the salt had the highest electrical conductivity in the order of 10–4 S cm–1. It was concluded from the dielectric, tangent and modulus spectra that the UPVA20 membrane was good at its properties. Thus, electric double layer capacitor was constructed with UPVA20 membrane as the separator. The capacitance value of the electric double layer capacitor determined from cyclic voltammetry was found to be 1652 mF g–1. The ultrasound assisted preparation of polymer membranes were good at performance when compared with the polymer membranes of ultrasound unassisted preparation. Among all the polymer electrolytes, UPVA20 polymer membrane had high conductivity, potential stability and capacitance.

scholarly journals Investigation of the Ionic Liquid Graphene Electric Double Layer in Supercapacitors Using Constant Potential Simulations

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2181
Author(s):  
Baris Demir ◽  
Debra Searles
Keyword(s):  
Molecular Dynamics ◽  
Ionic Liquids ◽  
Double Layer ◽  
Electric Double Layer ◽  
Potential Method ◽  
Bulk Region ◽  
Structure And Dynamics ◽  
Constant Potential ◽  
Dynamics Simulations ◽  
O 10

In this work, we investigate the effect of the cation structure on the structure and dynamics of the electrode–electrolyte interface using molecular dynamics simulations. A constant potential method is used to capture the behaviour of 1-ethyl-3-methylimidazolium bis (trifluoromethane)sulfonimide ([C2mim][NTf2]) and butyltrimethylammonium bis(trifluoromethane) sulfonimide ([N4,1,1,1][NTf2]) ionic liquids at varying potential differences applied across the supercapacitor. We find that the details of the structure in the electric double layer and the dynamics differ significantly, yet the charge profile and capacitance do not vary greatly. For the systems considered, charging results in the rearrangement and reorientation of ions within ∼1 nm of the electrode rather than the diffusion of ions to/from the bulk region. This occurs on timescales of O(10 ns) for the ionic liquids considered, and depends on the viscosity of the fluid.

In Situ Hard X-ray Photoelectron Spectroscopy of Space Charge Layer in a ZnO-Based All-Solid-State Electric Double-Layer Transistor

2019 ◽  
Vol 123 (16) ◽  
pp. 10487-10493 ◽  
Author(s):  
Takashi Tsuchiya ◽  
Yaomi Itoh ◽  
Yoshikazu Yamaoka ◽  
Shigenori Ueda ◽  
Yukihiro Kaneko ◽  
...  
Keyword(s):  
Solid State ◽  
Space Charge ◽  
Double Layer ◽  
Photoelectron Spectroscopy ◽  
Electric Double Layer ◽  
Space Charge Layer ◽  
X Ray ◽  
Charge Layer

Understanding the charging dynamics of an ionic liquid electric double layer capacitor via molecular dynamics simulations

2019 ◽  
Vol 21 (13) ◽  
pp. 6790-6800 ◽  
Author(s):  
Chanwoo Noh ◽  
YounJoon Jung
Keyword(s):  
Molecular Dynamics ◽  
Ionic Liquid ◽  
Double Layer ◽  
Electric Double Layer ◽  
Md Simulations ◽  
Electric Double Layer Capacitor ◽  
Double Layer Capacitor ◽  
Non Equilibrium Molecular Dynamics ◽  
Dynamics Simulations ◽  
Charging Dynamics

We investigate the charging phenomena of an electric double layer capacitor (EDLC) by conducting both equilibrium and non-equilibrium molecular dynamics (MD) simulations.

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