Low-Temperature Hydrothermal Synthesis and Electrochemical Properties of Birnessit-Type Manganese Dioxide Nanosheets

2013 ◽  
Vol 800 ◽  
pp. 393-397 ◽  
Author(s):  
De Yan ◽  
Ying Liu ◽  
Zhi Guo Wu ◽  
Ren Fu Zhuo ◽  
Jun Wang
Keyword(s):  
Low Temperature ◽  
Current Density ◽  
High Current Density ◽  
Hydrothermal Process ◽  
Rate Capability ◽  
High Specific Capacitance ◽  
High Current ◽  
Cycle Stability ◽  
Good Rate Capability ◽  
A Current

Birnessite MnO2 nanosheets were synthesized by self-limiting deposition of KMnO4 in a facile low-temperature hydrothermal process. The MnO2 electrode exhibits a high specific capacitance of 169 F g-1 at a current density of 0.1 A g-1, good rate capability with a capacitance of 96 F g-1 even at a high current density of 5 A g-1, as well as excellent cycle stability with capacitance retention of 94% at 1 A g-1 after 1,000 cycles.

scholarly journals Synthesis of Hierarchical Porous Ni1.5Co1.5S4/g-C3N4 Composite for Supercapacitor with Excellent Cycle Stability

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1631
Author(s):  
Fangzhou Jin ◽  
Xingxing He ◽  
Jinlong Jiang ◽  
Weijun Zhu ◽  
Jianfeng Dai ◽  
...  
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Low Cost ◽  
High Specific Capacitance ◽  
High Energy ◽  
High Energy Density ◽  
Cycle Stability ◽  
Hydrothermal Route ◽  
Supercapacitor Application ◽  
Hierarchical Porous

In this work, the hierarchical porous Ni1.5Co1.5S4/g-C3N4 composite was prepared by growing Ni1.5Co1.5S4 nanoparticles on graphitic carbon nitride (g-C3N4) nanosheets via a hydrothermal route. Due to the self-assembly of larger size g-C3N4 nanosheets as a skeleton, the prepared nanocomposite possesses a unique hierarchical porous structure that can provide short ions diffusion and fast electron transport. As a result, the Ni1.5Co1.5S4/g-C3N4 composite exhibits a high specific capacitance of 1827 F g−1 at a current density of 1 A g−1, which is 1.53 times that of pure Ni1.5Co1.5S4 (1191 F g−1). In particular, the Ni1.5Co1.5S4/g-C3N4//activated carbon (AC) asymmetric supercapacitor delivers a high energy density of 49.0 Wh kg−1 at a power density of 799.0 W kg−1. Moreover, the assembled device shows outstanding cycle stability with 95.5% capacitance retention after 8000 cycles at a high current density of 10 A g−1. The attractive performance indicates that the easily synthesized and low-cost Ni1.5Co1.5S4/g-C3N4 composite would be a promising electrode material for supercapacitor application.

Preparation of lignite-based activated carbon with high specific capacitance for electrochemical capacitors

2015 ◽  
Vol 08 (04) ◽  
pp. 1550031 ◽  
Author(s):  
Baolin Xing ◽  
Jianliang Cao ◽  
Yan Wang ◽  
Guiyun Yi ◽  
Chuanxiang Zhang ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Electron Microscope ◽  
Specific Capacitance ◽  
Current Density ◽  
Electrode Materials ◽  
High Current Density ◽  
Electrochemical Capacitors ◽  
High Specific Capacitance ◽  
High Current ◽  
Charge Discharge

A lignite-based activated carbon (LAC) for electrochemical capacitors (ECs) was prepared from high moisture lignite by KOH activation, and the as-prepared sample was characterized by the N 2-sorption, scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The electrochemical performances of ECs with activated carbon as electrodes in 3 M KOH aqueous solution were evaluated by constant current charge-discharge and cyclic voltammetry. The LAC exhibits a well-developed surface area of 2581 m2/g, a relative wide pore size distribution of 0.5–10 nm. The ECs with LAC as electrode materials presents a high specific capacitance of 392 F/g at a low current density of 50 mA/g, and still remains 315 F/g even at a high current density of 5 A/g. The residual specific capacitance is as high as 92.9% after 2000 cycles. Compared with the commercial activated carbon (Maxsorb: Commercial product, Kansai, Japan), the LAC based electrode materials shows superior capacitive performance in terms of specific capacitance and charge–discharge performance at the high current density.

THE ELECTROLYSIS OF SOME ORGANIC COMPOUNDS WITH ALTERNATING CURRENT

1939 ◽  
Vol 17b (5) ◽  
pp. 147-158 ◽  
Author(s):  
J. W. Shipley ◽  
M. T. Rogers
Keyword(s):  
Hydrochloric Acid ◽  
Organic Compounds ◽  
Current Density ◽  
Irreversible Process ◽  
High Current Density ◽  
Current Yield ◽  
High Current ◽  
Hydrogen Overvoltage ◽  
General Relations ◽  
A Current

The a-c. electrolysis of a number of organic compounds was carried out in order to ascertain what products might be obtained, what electrolytic conditions affected the nature and the yield of products, and to discover the general relations governing oxidation and reduction when a.c. is used. Oxidation was found to predominate over reduction, owing, probably, to the relatively low hydrogen overvoltage on the electrodes. The effect of varying the conditions of a-c. electrolysis was in general similar to that observed in d-c. electrolysis. Satisfactory yields were obtained only when a product of an irreversible process was concerned. A good yield of quinhydrone from the a-c. electrolysis of hydroquinone was secured at a relatively high current density. The chlorination of acetone by the a-c. electrolysis of a solution of acetic anhydride in hydrochloric acid gave a current yield of 35% at a current density of 2 amp. per cm2.

scholarly journals Hierarchical Porous Carbon Derived from Sichuan Pepper for High-Performance Symmetric Supercapacitor with Decent Rate Capability and Cycling Stability

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 553 ◽  
Author(s):  
Hengshuo Zhang ◽  
Wei Xiao ◽  
Wenjie Zhou ◽  
Shanyong Chen ◽  
Yanhua Zhang
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
High Current Density ◽  
Rate Capability ◽  
Cycling Stability ◽  
Koh Activation ◽  
High Current ◽  
Symmetric Supercapacitor ◽  
Hierarchical Porous

Hierarchical micro-mesoporous carbon (denoted as HPC-2 in this study) was synthesized by pre-carbonization of biomass Sichuan pepper followed by KOH activation. It possessed well-developed porosity with the specific surface area of 1823.1 m2 g−1 and pore volume of 0.906 cm3 g−1, and exhibited impressive supercapacitive behaviors. For example, the largest specific capacitance of HPC-2 was tested to be ca. 171 F g−1 in a three-electrode setup with outstanding rate capability and stable electrochemical property, whose capacitance retention was near 100% after cycling at rather a high current density of 40 A g−1 for up to 10,000 cycles. Furthermore, a two-electrode symmetric supercapacitor cell of HPC-2//HPC-2 was constructed, which delivered the maximum specific capacitance and energy density of ca. 30 F g−1 and 4.2 Wh kg−1, respectively, had prominent rate performance and cycling stability with negligible capacitance decay after repetitive charge/discharge at a high current density of 10 A g−1 for over 10,000 cycles. Such electrochemical properties of HPC-2 in both three- and two-electrode systems are superior or comparable to those of a great number of porous biomass carbon reported previously, hence making it a promising candidate for the development of high-performance energy storage devices.

Low Temperature Thin-film Silicon Diodes for Consumer Electronics

2005 ◽  
Vol 862 ◽  
Author(s):  
Qi Wang ◽  
Scott Ward ◽  
Anna Duda ◽  
Jian Hua ◽  
Paul Stradins ◽  
...  
Keyword(s):  
Thin Film ◽  
Low Temperature ◽  
Current Density ◽  
Voltage Drop ◽  
High Current Density ◽  
Consumer Electronics ◽  
High Current ◽  
Plastic Substrates ◽  
Forward Current ◽  
Thin Film Silicon

AbstractWe have developed high current density thin-film silicon n-i-p diodes for low cost and low temperature two-dimensional diode-logic memory array applications. The diodes are fabricated at temperatures below 250°C on glass, stainless steel, and plastic substrates using hot-wire chemical vapor deposition (CVD). The 0.01-mm2 standalone diodes have a forward current-density (J) of near 10 kA/cm2 and a rectification ratio over 107 at ±2 V. The 25 μm2 array diodes have J > 104 A/cm2 and rectification of 105 at ±2V. On plastic substrates, we have also used plasma-enhanced CVD to deposit 10-μm diameter diodes with J ˜ 5 x 104 A/cm2. We found that the use of microcrystalline silicon (μc-Si) i- and nlayers results in higher current-density diodes than with amorphous silicon. Reducing the diode area increases the forward current density by lowering the voltage drop across the external series resistances. A prototype diode array memory based on 10-micron devices was successfully demonstrated by monolithically integrating diodes with a-Si:H switching elements. High current density diodes have potential applications in a variety of large area, thin-film electronic devices, in addition to a-Si:H-based memory. This could widen the application of thin-film silicon beyond its present industrial applications in thin-film transistors, solar cells, bolometers and photo-detectors.

Simulation of Electrothermal Characteristics of 1200V/75A 4H-SiC JBS

2019 ◽  
Vol 954 ◽  
pp. 139-143
Author(s):  
Hang Gu ◽  
Yi Dan Tang ◽  
Lan Ge ◽  
Yun Bai ◽  
You Run Zhang ◽  
...  
Keyword(s):  
Schottky Diode ◽  
Current Density ◽  
Positive Feedback ◽  
High Current Density ◽  
Thermal Sensitivity ◽  
Junction Temperature ◽  
High Current ◽  
Electrothermal Simulation ◽  
Heating Mode ◽  
A Current

In this paper the electrothermal properties of the 4H-SiC JBS (Junction barrier Schottky) diode is investigated. FloTHERM and Silvaco TCAD are used for electrothermal simulation at the same time. Firstly, the effect of Rjc (junction-to-case thermal resistance) on junction temperature is investigated, the result shows that the junction temperature is more sensitive to the Rjc in the current heating mode because of some kind of positive feedback. Then, a current pulse is applied to the JBS, result shows that this kind of positive feedback is especially noticeable. Finally, the JBS will be compared with PIN under high current density pulsed operation, in order to analyze their thermal sensitivity to Rjc.

A durable VO2(M)/Zn battery with ultrahigh rate capability enabled by pseudocapacitive proton insertion

2020 ◽  
Vol 8 (4) ◽  
pp. 1731-1740 ◽  
Author(s):  
Lishang Zhang ◽  
Ling Miao ◽  
Bao Zhang ◽  
Jinsong Wang ◽  
Jia Liu ◽  
...  
Keyword(s):  
Current Density ◽  
Cathode Surface ◽  
High Current Density ◽  
Rate Capability ◽  
Electrochemical Process ◽  
High Current ◽  
Long Term Stability ◽  
Hydrate Deposition ◽  
Sulfate Hydrate

Reversible hydroxyzinc sulfate hydrate deposition/dissolution in electrochemical process could be observed on cathode surface. Good long term stability retention could also be achieved at high current density of 20 A g−1.

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