scholarly journals Modeling galvanostatic charge–discharge of nanoporous supercapacitors

2021 ◽  
Author(s):  
Liang Zeng ◽  
Taizheng Wu ◽  
Ting Ye ◽  
Tangming Mo ◽  
Rui Qiao ◽  
...  
Keyword(s):  
Potential Method ◽  
Discharge Process ◽  
Galvanostatic Charge ◽  
Galvanostatic Mode ◽  
Modeling Approach ◽  
Realistic Description ◽  
Constant Potential ◽  
Adsorption Desorption ◽  
Dynamics Process ◽  
Charge Discharge

AbstractMolecular modeling has been considered indispensable in studying the energy storage of supercapacitors at the atomistic level. The constant potential method (CPM) allows the electric potential to be kept uniform in the electrode, which is essential for a realistic description of the charge repartition and dynamics process in supercapacitors. However, previous CPM studies have been limited to the potentiostatic mode. Although widely adopted in experiments, the galvanostatic mode has rarely been investigated in CPM simulations because of a lack of effective methods. Here we develop a modeling approach to simulating the galvanostatic charge–discharge process of supercapacitors under constant potential. We show that, for nanoporous electrodes, this modeling approach can capture experimentally consistent dynamics in supercapacitors. It can also delineate, at the molecular scale, the hysteresis in ion adsorption–desorption dynamics during charging and discharging. This approach thus enables the further accurate modeling of the physics and electrochemistry in supercapacitor dynamics.

scholarly journals Modeling galvanostatic charge-discharge of nanoporous supercapacitors

2021 ◽  
Author(s):  
Liang Zeng ◽  
Taizheng Wu ◽  
Ting Ye ◽  
Tangming Mo ◽  
Rui Qiao ◽  
...  
Keyword(s):  
Potential Method ◽  
Galvanostatic Charge ◽  
Galvanostatic Mode ◽  
Potentiostatic Mode ◽  
Realistic Description ◽  
Constant Potential ◽  
The Rich ◽  
Adsorption Desorption ◽  
Dynamics Process ◽  
Charge Discharge

Abstract Molecular modeling can study the energy storage of supercapacitors at the atomistic level and has become indispensable in this research. The constant potential method (CPM) allows keeping the electric potential uniform on the electrode, which is essential for a realistic description of the charge repartition and dynamics process in supercapacitors. Prior CPM studies have been limited to the potentiostatic mode. Though widely adopted in the experiment, the galvanostatic mode has been rarely investigated in CPM simulations due to a lack of effective methods. In this work, we developed a modeling approach to simulating the galvanostatic charge-discharge of supercapacitors under constant potential (GCD-CPM). We show that, for nanoporous electrodes, GCD-CPM can capture supercapacitor dynamics in excellent agreement with experimental measurements and delineate the ion adsorption-desorption dynamics underlying the hysteresis with molecular resolutions during charging and discharging. Therefore, this GCD-CPM modeling could open up new avenues for exploring the rich physics and electrochemistry of supercapacitor dynamics.

Hydrothermal Synthesis and Electrochemical Study of VOx/CNTs Composites

2009 ◽  
Vol 79-82 ◽  
pp. 1787-1790
Author(s):  
Quan Yao Zhu ◽  
Si Ping Hu ◽  
Fei Wu ◽  
Wen Chen
Keyword(s):  
Carbon Nanotubes ◽  
Hydrothermal Synthesis ◽  
Sol Gel ◽  
Vanadium Oxides ◽  
Discharge Process ◽  
Galvanostatic Charge ◽  
Electrochemical Behaviors ◽  
Morphology And Structure ◽  
Ft Ir ◽  
Charge Discharge

Vanadium oxide/carbon nanotubes (VOx/CNTs) composites were prepared by sol-gel hydrothermal synthesis. The composites were characterized in terms of surface morphology and structure using SEM, TEM, XRD, FT-IR, respectively. The electrochemical behaviors of the composites were investigated by means of galvanostatic charge-discharge cycling. The result shows that the vanadium oxides nanotubes and carbon nanotubes contacted each other and the composites have great cycleability as well as capacity characteristics which arrived at 303.5 mAh/g in the first discharge process and 200.4 mAh/g after 50th discharge cycles.

Single atom catalysts supported on N-doped graphene toward fast kinetic Li−S batteries: a theoretical study

2021 ◽  
Author(s):  
Xu Han ◽  
Zeyun Zhang ◽  
Xuefei Xu
Keyword(s):  
Theoretical Study ◽  
Single Atom ◽  
Discharge Process ◽  
Fast Kinetics ◽  
Shuttle Effect ◽  
Sufficient Stability ◽  
Doped Graphene ◽  
Fast Kinetic ◽  
Kinetics Of ◽  
Charge Discharge

To suppress the shuttle effect of lithium polysulfides and promote fast kinetics of charge−discharge process in Li−S batteries, it is essential to search promising catalysts with sufficient stability and high...

Li0.95Na0.05Ti2(PO4)3/C with Good Performance as Anode Material for Aqueous Rechargeable Lithium Batteries

2014 ◽  
Vol 989-994 ◽  
pp. 316-319 ◽  
Author(s):  
Jing Zhu ◽  
Yong Guang Liu ◽  
Qing Qing Tian ◽  
Ling Wang ◽  
Ji Lin Cao
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Performance ◽  
Anode Material ◽  
Lithium Batteries ◽  
Sol Gel ◽  
Nasicon Structure ◽  
Galvanostatic Charge ◽  
Rechargeable Lithium Batteries ◽  
Structure And Morphology ◽  
Charge Discharge

Li0.95Na0.05Ti2(PO4)3/C nanocomposite was prepared by sol-gel method.The structure and morphology of the samples were characterized by XRD, SEM which showed the particles had typical NASICON structure and diameter range from 400~500nm. The electrochemical performance were tested by cyclic voltammetry and galvanostatic charge–discharge. Results show Li0.95Na0.05Ti2(PO4)3/C nanocomposite exhibitsmuch better electrochemical performance than bare Li0.95Na0.05Ti2(PO4)3.

Preparation and Electrochemical Properties of LaMnO3 Powder as a Supercapacitor Electrode Material

2017 ◽  
Vol 727 ◽  
pp. 698-704 ◽  
Author(s):  
Xian Wei Wang ◽  
Xiao Er Wang ◽  
Hui Chao Zhang ◽  
Qian Qian Zhu ◽  
Dong Li Zheng ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Properties ◽  
Electrode Material ◽  
Raw Materials ◽  
Sol Gel ◽  
Galvanostatic Charge ◽  
Supercapacitor Electrode ◽  
Lanthanum Manganate ◽  
Pure Phase ◽  
Charge Discharge

The structural and electrochemical properties of lanthanum manganate (LaMnO3) powder prepared by the sol-gel method are researched in this article. The powder calcined at 600 °C showed amorphous, and the powder calcined at 700-800 °C showed the pure phase of the LaMnO3. The grains with the size of about 80-120 nm were agglomerating together. Cyclic voltammetry and galvanostatic charge-discharge were used to characterize the electrochemical properties in alkaline environment. The electrochemical properties calcined at 700 °C showed a specific capacitance of 73 F/g at the current density of 0.5 A/g. The raw materials for preparing the LaMnO3 powder are cheap, and the operation method is simple.

scholarly journals Two-Electron Reaction without Structural Phase Transition in Nanoporous Cathode Material

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Tomoyuki Matsuda ◽  
Yutaka Moritomo
Keyword(s):  
Phase Transition ◽  
Cathode Material ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Discharge Process ◽  
Charge Capacity ◽  
High Charge ◽  
Valence States ◽  
X Ray Absorption ◽  
Charge Discharge

We investigated the charge/discharge properties, valence states, and structural properties of a nanoporous cathode materialLixMn[Fe(CN)6]0.83·3.5H2O. The film-type electrode ofLixMn[Fe(CN)6]0.83·3.5H2Oexhibited a high charge capacity(=128 mAh g-1)and a good cyclability (87% of the initial value after 100 cycles) and is one of the promising candidates for Li-ion battery cathode. X-ray absorption spectra near the Fe and Mn K-edges revealed that the charge/discharge process is a two-electron reaction; that is,MnII–NC–FeII,MnII–NC–FeIII, andMnIII–NC–FeIII. We further found that the crystal structure remains cubic throughout the charge/discharge process. The lattice constant slightly increased during the[FeII(CN)6]4-/[FeIII(CN)6]3-oxidization reaction while decreased during theMnII/MnIIIoxidization reaction. The two-electron reaction without structural phase transition is responsible for the high charge capacity and the good cyclability.

High Rate Charge/Discharge Characteristics in Composite Film of Mesoporous TiO2 and Polyaniline for Photorechargeable Battery

2014 ◽  
Vol 1606 ◽  
Author(s):  
Teruaki Nomiyama ◽  
Kenta Sakamoto ◽  
Tomohito Yoshida ◽  
Akinori Kagiyama ◽  
Yuji Horie
Keyword(s):  
Composite Film ◽  
High Performance ◽  
Specific Capacity ◽  
Electrical Energy ◽  
High Rate ◽  
Galvanostatic Charge ◽  
Discharge Characteristics ◽  
Electrical Energy Storage ◽  
Charging Rate ◽  
Charge Discharge

ABSTRACTOne of promising photorechargeable electrode, which has two functions of photovoltaic and electrical energy storage, is a composite film of mesoporous TiO2 and conducting polymer polyaniline. Galvanostatic charge/discharge characteristics of the TiO2-polyaniline composite were examined to reveal how fast the film was charged. The film with a specific capacity 60-120 mAh g–1 was found to be fully charged at high charging rate 20 mA cm–2 which is comparable to high performance solar cells. Such high charging rate was achieved by the compact polyaniline layer covering the large specific surface area of mesoporous TiO2 film.

scholarly journals Lithium-Rich Cobalt-Free Manganese-Based Layered Cathode Materials for Li-Ion Batteries: Suppressing the Voltage Fading

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3487
Author(s):  
Ashraf Abdel-Ghany ◽  
Ahmed M. Hashem ◽  
Alain Mauger ◽  
Christian M. Julien
Keyword(s):  
Layered Structure ◽  
Performance Enhancement ◽  
Electrochemical Impedance ◽  
Discharge Process ◽  
High Porosity ◽  
Li Ion Batteries ◽  
Hydrothermal Route ◽  
Li Ion ◽  
Fading Rate ◽  
Charge Discharge

Lithium-rich layered oxides are recognized as promising materials for Li-ion batteries, owing to higher capacity than the currently available commercialized cathode, for their lower cost. However, their voltage decay and cycling instability during the charge/discharge process are problems that need to be solved before their practical application can be envisioned. These problems are mainly associated with a phase transition of the surface layer from the layered structure to the spinel structure. In this paper, we report the AlF3-coating of the Li-rich Co-free layered Li1.2Ni0.2Mn0.6O2 (LLNMO) oxide as an effective strategy to solve these problems. The samples were synthesized via the hydrothermal route that insures a very good crystallization in the layered structure, probed by XRD, energy-dispersive X-ray (EDX) spectroscopy, and Raman spectroscopy. The hydrothermally synthesized samples before and after AlF3 coating are well crystallized in the layered structure with particle sizes of about 180 nm (crystallites of ~65 nm), with high porosity (pore size 5 nm) determined by Brunauer–Emmett–Teller (BET) specific surface area method. Subsequent improvements in discharge capacity are obtained with a ~5-nm thick coating layer. AlF3-coated Li1.2Ni0.2Mn0.6O2 delivers a capacity of 248 mAh g−1 stable over the 100 cycles, and it exhibits a voltage fading rate of 1.40 mV per cycle. According to the analysis from galvanostatic charge-discharge and electrochemical impedance spectroscopy, the electrochemical performance enhancement is discussed and compared with literature data. Post-mortem analysis confirms that the AlF3 coating is a very efficient surface modification to improve the stability of the layered phase of the Li-rich material, at the origin of the significant improvement of the electrochemical properties.

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