scholarly journals High Photocurrent Density and Continuous Electron Emission Characterization of a Multi-Alkali Antimonide Photocathode

Electronics ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1991
Author(s):  
Jun Dai ◽  
Yikun Ding ◽  
Cunjun Ruan ◽  
Xiangyan Xu ◽  
Hulin Liu
Keyword(s):  
Electric Fields ◽  
Current Density ◽  
Electron Emission ◽  
Continuous Wave ◽  
High Current Density ◽  
Optical Power ◽  
Photocurrent Density ◽  
Maximum Current ◽  
Section Electron

High photocurrent density cathodes that enable small cross-section electron beams are required for high-power terahertz vacuum devices. Multi-alkali antimonide photocathodes may be well suited for generating sub-mm electron beam sources. This paper involves the repeatability, stability, uniformity, and linearity experiments of the multi-alkali antimonide photocathodes electron emission operations under a continuous-wave 450 nm laser with a bias voltage of 5000 V. The effect of heat, electric contact, and cathode surface roughness to emission characterizations is analyzed. The methods to maintain the high-current-density emission and avoid the fatigue of the photocathode are verified. The emission can be repeated with increased optical power. The stable photocurrent density of near 1 A/cm2 and maximum current density of near 1.43 A/cm2 is recorded. The continuous photocurrent density is significantly improved compared to the current density reported in traditional applications. It is found that the current curves measuring at different areas of the photocathode differ greatly after the laser power of 800 mW. The increase in current for some areas may be attributed to the conductive current caused by built-in electric fields between the emission rough area and its adjacent areas.

scholarly journals Lamellar Polypyrene Based on Attapulgite–Sulfur Composite for Lithium–Sulfur Battery

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 483
Author(s):  
Jing Wang ◽  
Riwei Xu ◽  
Chengzhong Wang ◽  
Jinping Xiong
Keyword(s):  
Cathode Material ◽  
Current Density ◽  
High Current Density ◽  
Specific Capacity ◽  
Lithium Sulfur Batteries ◽  
Rate Test ◽  
Sulfur Battery ◽  
Lower Capacity ◽  
Lithium Sulfur

We report on the preparation and characterization of a novel lamellar polypyrrole using an attapulgite–sulfur composite as a hard template. Pretreated attapulgite was utilized as the carrier of elemental sulfur and the attapulgite–sulfur–polypyrrole (AT @400 °C–S–PPy) composite with 50 wt.% sulfur was obtained. The structure and morphology of the composite were characterized with infrared spectroscopy (IR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). An AT @400 °C–S–PPy composite was further utilized as the cathode material for lithium–sulfur batteries. The first discharge specific capacity of this kind of battery reached 1175 mAh/g at a 0.1 C current rate and remained at 518 mAh/g after 100 cycles with capacity retention close to 44%. In the rate test, compared with the polypyrrole–sulfur (PPy–S) cathode material, the AT @400 °C–S–PPy cathode material showed lower capacity at a high current density, but it showed higher capacity when the current came back to a low current density, which was attributed to the “recycling” of pores and channels of attapulgite. Therefore, the lamellar composite with special pore structure has great value in improving the performance of lithium–sulfur batteries.

TiN-nanorod-coated carbon fiber cathode for high-current-density electron emission

Vacuum ◽  
2019 ◽  
Vol 162 ◽  
pp. 137-144 ◽  
Author(s):  
Limin Li ◽  
Songling Fu ◽  
Xiuxiang Huang ◽  
Qiang Tang ◽  
Ke Peng ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Current Density ◽  
Electron Emission ◽  
High Current Density ◽  
High Current ◽  
Coated Carbon

Preparation and Characterization of CMC-PVA/PVA-SA-MePc (COOH)8/CS-PVA Bipolar Membrane Using Electrospinning Technique

2013 ◽  
Vol 774-776 ◽  
pp. 795-798
Author(s):  
Ting Jin Zhou ◽  
Min Lu ◽  
Ri Yao Chen
Keyword(s):  
Polyvinyl Alcohol ◽  
Water Splitting ◽  
Current Density ◽  
Voltage Drop ◽  
High Current Density ◽  
High Current ◽  
Bipolar Membrane ◽  
Electrospinning Technique ◽  
Exchange Layer

Carboxymethyl cellulose (CMC)-polyvinyl alcohol (PVA) and chitosan (CS)-polyvinyl alcohol were cross-linked by Fe3+and glutaraldehyde respectively to prepare cation exchange layer and anion exchange layer, and polyvinyl alcohol-sodium alginate (SA)-metal octocarboxyphthalocyanine (MePc (COOH)8, a kind of water splitting catalyst, here, Me stands for Fe3+or Co2+) nanofibers were prepared by electrospinning technique and introduced into the interlayer to obtain the CMC-PVA/PVA-SA-MePc (COOH)8/CS-PVA bipolar membrane (BPM). The experimental results showed that compared with the BPM without the PVA-SA-MePc (COOH)8interlayer, the water splitting efficiency at the interlayer of the CMC-PVA/PVA-SA-MePc (COOH)8/ CS-PVA BPM was obviously increased, and its membrane impedance decreased. When the concentration of FePc (COOH)8in the PVA-SA-FePc (COOH)8nanofibers was 3.0%, the trans-membrane voltage drop (IRdrop) of the CMC-PVA/PVA-SA-FePc (COOH)8/CS-PVA BPM was as low as 0.6V at a high current density of 90 mA/cm2.

scholarly journals High Current Density Chronopotentiometric Electrosynthesis and SEM Characterization of Hexanethiol-Monolayer-Protected Silver Planar Nanotriangles (Ag@C6SH)

2016 ◽  
Vol 2016 ◽  
pp. 1-12
Author(s):  
DJafar Vatan Khah Dowlat Sara ◽  
Ahmad Rouhollahi ◽  
Seied Mahdi Pourmortazavi ◽  
Mojtaba Shamsipur
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Average Particle Size ◽  
Average Particle ◽  
Nonaqueous Media ◽  
Experimental Conditions ◽  
Vis Spectroscopy ◽  
Optimized Conditions ◽  
First Time

This work reports for the first time electrosynthesis of hexanethiol capped silver nanotriangles cores (Ag@C6SH NCs) by a rapid, clean, and simple Double Pulse Chronopotentiometric (DCP) method in nonaqueous media, using a Taguchi orthogonal arrayL8design to identify the optimized experimental conditions. It was found that the size and shape of the product could be tuned by the current density, electrolysis time, electrode distance, and amount of NaBH4% used. The Ag@C6SH NCs in different shapes and sizes (in the range of 30 to 44 nm as an average estimation) were synthesized, under different experimental conditions. Finally, the as-prepared nanoclusters electrosynthesized at optimized conditions were characterized by SEM, XRD, and UV-Vis spectroscopy. The average particle size of the triangular/pyramidal shape (Ag@C6SH NCs), obtained under optimized experimental conditions, was30.5±2.0 nm but the majority of nanoparticles in TC3SEM are so much finer.

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