scholarly journals Treatment of NiMoO4/nanographite nanocomposite electrodes using flexible graphite substrate for aqueous hybrid supercapacitors

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254023
Author(s):  
Shahrzad Arshadi Rastabi ◽  
Rasoul Sarraf-Mamoory ◽  
Ghadir Razaz ◽  
Nicklas Blomquist ◽  
Magnus Hummelgård ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Active Material ◽  
Current Collector ◽  
Graphite Substrate ◽  
Discharge Process ◽  
Graphite Foil ◽  
Current Densities ◽  
Flexible Graphite ◽  
Foil Substrate ◽  
Charge Discharge

The cycling performance of supercapacitors sometimes becomes limited when electrode materials slough off during frequent charge–discharge cycles, due to weak bonding between the active material and the current collector. In this work, a flexible graphite foil substrate was successfully used as the current collector for supercapacitor electrodes. Graphite foil substrates were treated in different ways with different acid concentrations and temperatures before being coated with an active material (NiMoO4/nanographite). The electrode treated with HNO3 (65%) and H2SO4 (95%) in a 1:1 ratio at 24°C gave better electrochemical performance than did electrodes treated in other ways. This electrode had capacitances of 441 and 184 Fg–1 at current densities of 0.5 and 10 Ag-1, respectively, with a good rate capability over the current densities of the other treated electrodes. SEM observation of the electrodes revealed that NiMoO4 with a morphology of nanorods 100–120 nm long was properly accommodated on the graphite surface during the charge–discharge process. It also showed that treatment with high-concentration acid created an appropriately porous and rough surface on the graphite, enhancing the adhesion of NiMoO4/nanographite and boosting the electrochemical performance.

scholarly journals Electrochemical Performance of Molybdenum Disulfide Supercapacitor Electrode in Potassium Hydroxide and Sodium Sulfate Electrolytes

2020 ◽  
Vol 8 (6) ◽  
pp. 5499-5503
Keyword(s):  
Molybdenum Disulfide ◽  
Active Material ◽  
Current Collector ◽  
Future Application ◽  
Energy Storage Materials ◽  
Discharge Process ◽  
Supercapacitor Electrode ◽  
Optical And Mechanical Properties ◽  
Interest In Research ◽  
Charge Discharge

Two-dimensional materials have attracted growing interest in research because of their specific electronic, physical, optical and mechanical properties. Molybdenum disulfide was theoretically investigated as novel energy storage materials because of its unusual physicochemical properties. This paper describes easy approach to fabricate molybdenum disulfide (MoS2 ) electrode using slurry technique on conducting substrate namely Ni foam as current collector for supercapacitor device application. This MoS2 electrode exhibits relatively good specific gravimetric capacitance, (Csp) of 11.12 to 12.38 Fg -1 at 1 mVs -1 scan rate. Moreover, galvanostatic charge-discharge displays symmetrical triangular curves which attributed to the fast charge-discharge process (in seconds). These results show that MoS2 active material can be charged and discharged reversibly between 0.2 and 1.0 V (in 6 M KOH) and between 0.3 and 1.0 V (in 0.5 M Na2SO4 ). From cyclic stability test exhibits capacitance retention of up to 83% and 64% after 1000 cycles in 6 M KOH and 0.5 M Na2SO4 , respectively. The MoS2 electrode is thus a promising material for future application of the supercapacitor.

Influence of Nanosized α-Ni(OH)2 Addition on the Electrochemical Performance of β-Ni(OH)2 Electrode

2007 ◽  
Vol 121-123 ◽  
pp. 1265-1268 ◽  
Author(s):  
T.A. Han ◽  
J.P. Tu ◽  
Jian Bo Wu ◽  
Y.F. Yuan ◽  
Y. Li
Keyword(s):  
Electrochemical Performance ◽  
Active Material ◽  
Spherical Shape ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
Galvanostatic Charge ◽  
X Ray ◽  
Co Precipitation ◽  
Charge Discharge ◽  
Scanning Electron

Al-substituted α-Ni(OH)2 was synthesized by a chemical co-precipitation. The as-prepared α-Ni(OH)2 particles were characterized by the means of X-ray diffraction (XRD) and scanning electron microscope (SEM). The obtained α-Ni(OH)2 particles were well crystallized, spherical shape with the particle sizes of 20-35 nm. The electrochemical performance of β-Ni(OH)2 electrode with addition of nanosized α-Ni(OH)2 was investigated by galvanostatic charge-discharge tests. The nanosized α-Ni(OH)2 as additive in the commercial microsized spherical β-Ni(OH)2 electrode improved the discharge capability. As compared to commercial β-Ni(OH)2 electrode, the electrode with nanosized α-Ni(OH)2 exhibited excellent better charge-discharge cycling stability. It may be a promising positive active material for alkaline secondary batteries.

scholarly journals Electrochemical Properties of PANI as Single Electrode of Electrochemical Capacitors in Acid Electrolytes

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Haihua Zhu ◽  
Shunjin Peng ◽  
Weijie Jiang
Keyword(s):  
Electrochemical Properties ◽  
Chemical Structure ◽  
Active Material ◽  
Electrochemical Capacitor ◽  
Current Collector ◽  
Carbon Paper ◽  
Solution Polymerization ◽  
Chemical Solution ◽  
Galvanostatic Charge ◽  
Charge Discharge

The polyaniline (PANI) powder with globular sponge-like morphology was prepared by chemical solution polymerization, and its morphology and chemical structure were characterized by scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The single electrode of electrochemical capacitor was made using the prepared PANI powder as active material and carbon paper as current collector. Electrochemical properties of PANI as a single electrode in 1 M HCl and 1 M H2SO4electrolyte solution were tested by galvanostatic charge/discharge (GCD) and cyclic voltammetry (CV) techniques. It has been found that PANI has higher specific capacitance of 302.43 Fg−1, higher specific energy of 54.44 Wh·kg−1at 0.5 Ag−1, and higher working potential in 1 M HCl than those in 1 M H2SO4.

scholarly journals Quasi-3D modeling of Li-ion batteries based on single 2D image

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Yoichi Takagishi ◽  
Takumi Yamanaka ◽  
Tatsuya Yamaue
Keyword(s):  
3D Model ◽  
Ion Beam ◽  
Active Material ◽  
3D Structure ◽  
Porous Electrodes ◽  
Ion Concentration ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Charge Discharge

Abstract Electrochemical physics-based simulations of Li-ion batteries using a mesoscale 3D structure of porous electrodes are one of the most effective approaches for evaluating the local Li concentration in active materials and the Li-ion concentration in electrolytes. However, this approach requires considerable computational resources compared with a simple 2D or 1D homogeneous simulation. In this work, we developed an advanced electrochemical physics-based simulation method for Li-ion batteries that enabled a quasi-3D simulation of charge/discharge using only a single 2D slice image. The governing equations were based on typical theories of electrochemical reactions and ion transport. From referencing the 2D plane, the model was able to simulate both the Li concentration in the active material and the Li-ion concentration in the electrolyte for their subsequent consideration in a virtual 3D structure. To confirm the validity of our proposed model, a full 3D discharge simulation with randomly packed active material particles was performed and compared with the results of the quasi-3D model and a simple-2D model. Results indicated that the quasi-3D model properly reproduced the sliced Li and Li-ion concentrations simulated by the full 3D model in the charge/discharge process, whereas the simple-2D simulation partially overestimated or underestimated these concentrations. In addition, the quasi-3D model made it possible to dramatically decrease the computation time compared to the full-3D model. Finally, we applied the model to an actual scanning electron microscopy equipped with a focused ion beam (FIB-SEM) image of a positive electrode. Graphic abstract

scholarly journals Quasi-3D Modeling of Li-ion Batteries Based on Single 2D Image

2021 ◽  
Author(s):  
Yoichi Takagishi ◽  
Tatsuya Yamaue ◽  
Takumi Yamanaka
Keyword(s):  
3D Model ◽  
Ion Beam ◽  
Active Material ◽  
3D Structure ◽  
Simulation Method ◽  
Ion Concentration ◽  
Discharge Process ◽  
Li Ion Batteries ◽  
Li Ion ◽  
Charge Discharge

In this work, we developed an advanced electrochemical physics-based simulation method for Li-ion batteries that enabled a quasi-3D simulation of charge/discharge using only a single 2D slice image. The governing equations are based on typical theories of electrochemical reactions and ion transport. From referencing the 2D plane, the model was able to simulate both the Li concentration in the active material and the Li-ion concentration in the electrolyte for their subsequent consideration in a virtual 3D structure. To confirm the validity of our proposed model, a full 3D discharge simulation with randomly packed active material particles was performed and compared with the results of the quasi-3D model and a simple-2D model. Results indicated that the quasi-3D model properly reproduced the sliced Li and Li-ion concentrations simulated by the full 3D model in the charge/discharge process, whereas the simple-2D simulation partially overestimated or underestimated these concentrations. Finally, we applied the model to an actual Scanning Electron Microscopy equipped with a Focused Ion Beam (FIB-SEM) image of a positive electrode.

DIRECT CONTACT SHIELD OF LiMn2O4 ACTIVE MATERIAL FROM ELECTROLYTE

2010 ◽  
Vol 17 (01) ◽  
pp. 81-86 ◽  
Author(s):  
MYOUNG HYE CHANG ◽  
CHANG WOO LEE
Keyword(s):  
Electrochemical Performance ◽  
Pure Aluminum ◽  
Sol Gel ◽  
Active Material ◽  
Lithium Ion ◽  
Chelating Agent ◽  
Current Collector ◽  
Aluminum Foil ◽  
Manganese Acetate ◽  
Thermal Environments

The spinel LiMn 2 O 4 powders were prepared by sol–gel technique using lithium acetate ( Li ( CH 3 COO ) · 2 H 2 O ) and manganese acetate ( Mn ( CH 3 COO )2 · 4 H 2 O ) as starting materials, citric acid as a chelating agent, and acrylamide as a gel formatting agent. In order to improve the electrochemical performance of lithium ion batteries and prevent structural disintegration from Mn dissolution generated by undesirable acid production, conductive agents were additionally coated on the surface of active material coated on pure aluminum foil as a current collector. Also, it was comparatively investigated using different conductive agents with different particle sizes as well as adopting the cells into the different thermal environments. The electrochemical performance of the Li/LiMn 2 O 4 cells demonstrated that the spinel LiMn 2 O 4 might be effectively shielded from acid, resulting in improved electrochemical capacity characteristics at room temperature as well as elevated temperature of 55°C.

The Effect of Binder in Electrode Materials for Capacitance Improvement and EDLC Binder-free Cell Design

2013 ◽  
Vol 16 (3) ◽  
pp. 197-202 ◽  
Author(s):  
R. López-Chavéz ◽  
A. K. Cuentas-Gallegos
Keyword(s):  
Polyvinylidene Fluoride ◽  
Electrode Materials ◽  
Active Material ◽  
Current Collector ◽  
Free Cell ◽  
Carbon Paper ◽  
Cell Design ◽  
Binder Type ◽  
Binder Free ◽  
Charge Discharge

In the present work we show results related with the influence of the binder type used to elaborate active electrodes made of activated carbon (DLC) for the assembly of supercapacitor cells. A Nafion 5%w solution and/or Kinar Flex (Polyvinylidene fluoride, PVDF) were used as binders at different concentrations, using DLC carbon as the active material to make the electrodes by aerography, and carbon paper as support and current collector. Thickness of the electrodes was controlled by the weight of active material (DLC carbon). Cyclic voltammetry technique was used to investigate the intrinsic capacitive nature of these electrodes, increasing this value from 120 F/g to 245 F/g at 20 mV/s just by improving the type and amount of binder, and the thickness of the electrode. Symmetric 2-electrode cells assembled with binder-free electrodes were electrochemically characterized by galvanostatic cycling, showing capacitance values of 38F/g and a stable behavior during 7000 charge-discharge cycles.

Electrochemical Performance of Activated Carbon Electrode Added with LiCoO2 for Hybrid Capacitor

2007 ◽  
Vol 124-126 ◽  
pp. 947-950 ◽  
Author(s):  
Ick Jun Kim ◽  
Min Je Jeon ◽  
Sun Hye Yang ◽  
Seong In Moon ◽  
Hyun Soo Kim
Keyword(s):  
Particle Size ◽  
Activated Carbon ◽  
Size Effect ◽  
Electrochemical Performance ◽  
Electrochemical Properties ◽  
Ball Milling ◽  
Active Material ◽  
Carbon Electrode ◽  
Volumetric Capacity ◽  
Charge Discharge

In this study, mixed active material electrodes, composed of an activated carbon (MSP20) and LiCoO2, were prepared as cathodes for a high-capacitive hybrid capacitor. The electrochemical properties of (MSP20+LiCoO2)/Li cells were examined in terms of the weight composition and the particle size of LiCoO2 powder in the electrodes. As adding more LiCoO2 powders in the electrode, the volumetric capacity (mAh/ml) of the electrode became higher. In order to examine the size effect on the electrochemical performance, the LiCoO2 powders were modified by ball milling. The (MSP20+LiCoO2)/Li cells using 10 and 20 wt.% of 30h-milled LiCoO2 powder exhibited the lower internal resistivities and the better capacity retentions after 100 charge-discharge cycles than those using 10 or 20 wt.% of raw LiCoO2 powders.

Recycling of Waste Toner and its Electrochemical Performances for Supercapacitor

2014 ◽  
Vol 675-677 ◽  
pp. 689-692
Author(s):  
Ji Qing Mao ◽  
Yang Li
Keyword(s):  
Heat Treatment ◽  
Cyclic Voltammetry ◽  
Electrode Material ◽  
Active Material ◽  
Electrochemical Performances ◽  
Discharge Process ◽  
Oxide Structure ◽  
Resource Recycling ◽  
Potential Alternative ◽  
Charge Discharge

Utilization of the waste toner in wasted print cartridge was beneficial to the environmental protection and resource recycling. Fe3O4 has been obtained from the waste toner via magnetic separation and heat-treatment in present study. XRD measurement revealed the recuperated sample has ferriferrous oxide structure without other crystalline impurity. The electrochemical performances of recuperated Fe3O4, as the electrode active material for supercapacitor, was conducted by cyclic voltammetry and charge-discharge process. The results showed that the specific capacitance of Fe3O4 achieved 76.5 F/g under 50 mA/g current density, which possessed typical capacitive behaviors and good cycling stabilities. Based on the preferable electrochemical performances, Fe3O4 recovered from waste toner may be a potential alternative as electrode material for supercapacitor.

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