Aerosol technology and Si nano-composite electrode assembly for Li-ion batteries

2011 ◽  
Vol 1313 ◽  
Author(s):  
David Munao ◽  
Mario Valvo ◽  
Jan van Erven ◽  
Esteban Garcia-Tamayo ◽  
Erik Kelder
Keyword(s):  
Particle Size ◽  
Hybrid Electric Vehicle ◽  
Chemical Vapor ◽  
Good Control ◽  
High Energy ◽  
Thin Layers ◽  
Nano Particles ◽  
High Energy Density ◽  
Clear Understanding ◽  
Silicon Based

ABSTRACTIn this work novel approaches to fabricate silicon-based electrodes are shown. Starting from silicon nano-particles it is possible to create nano-structured porous thin films. Both the synthesis of the Si nano-particles and the electrode assembly are performed via aerosol routes. This guarantees a very good control on the particle size and the particle size distribution, on the purity of the product and on the morphology and texture of the deposited layers. Particles are produced via Laser assisted Chemical Vapor Pyrolysis whereas electrode thin layers are deposited via Electro Spray method. The range of particle sizes can be tailored according to the selected application. Here, particles of a mean size of about 10 nm have been synthesized. Since Si is well known to forms highly lithiated intermetallic compounds [1], it is regarded as one of the most promising material for energy storage [2], especially looking at high energy density applications, such as hybrid/electric vehicle traction. In this work its promising performance are presented. The role of the additives in the composite formulation is also taken into account for a more clear understanding of the capacity fading mechanism of such electrodes.

scholarly journals Metal-Water mixtures for Propulsion and Energy-Conversion Applications: Recent Progress and Future Directions

2018 ◽  
Vol 20 (1) ◽  
pp. 53 ◽  
Author(s):  
Dilip Sundaram
Keyword(s):  
Particle Size ◽  
Energy Conversion ◽  
Experimental Studies ◽  
High Energy ◽  
High Energy Density ◽  
Full Potential ◽  
Predictive Tool ◽  
Practical Applications ◽  
Relative Safety ◽  
Metal Water

The metal-water system is attractive for propulsion and energy-conversion applications. Of all metals, aluminum is attractive due to its high energy density, relative safety, and low cost. Experimental studies provide new insight on the combustion and propulsive behaviors. The burning rate is found to be a strong function of both pressure and particle size. Furthermore, there is a wide scatter in the measured pressure exponents due to differences in particle size, pressure, pH, and equivalence ratio. A major problem with Al/H2O mixtures is incomplete combustion and poor impulses, thereby rendering Al/H2O mixtures unsuitable for practical applications. Efforts to improve the performance of Al/H2O mixtures have only met with moderate success. Although experiments have revealed these new trends, not much is offered in terms of the underlying physics and mechanisms. To explore the combustion mechanisms, theoretical models based on energy balance analysis have been developed. These models involve numerous assumptions and many complexities were either ignored or treated simplistically. The model also relies on empirical inputs, which makes it more a useful guide than a predictive tool. Future works must endeavor to conduct a more rigorous analysis of metal-water combustion. Empirical inputs should be avoided and complexities must be properly treated to capture the essential physics of the problem. The model should help us properly understand the experimental trends, offer realistic predictions for unexplored conditions, and suggest guidelines and solutions in order to realize the full potential of metal-water mixtures.

Low Temperature Plasma Enhanced CVD of ‘Device Quality’ Silicon Dioxide.

1987 ◽  
Vol 105 ◽  
Author(s):  
J. Batey ◽  
E. Tierney ◽  
T. N. Nguyen ◽  
J. W. Stasiak ◽  
J. Li
Keyword(s):  
Three Dimensional ◽  
Chemical Vapor ◽  
High Energy ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Thermal Budget ◽  
Direct Exposure ◽  
Energy Environment ◽  
Silicon Based ◽  
Substrate Temperatures

AbstractAs silicon-based technologies move towards submicron dimensions, vertical and three dimensional structures, the need for reduced thermal processing becomes more evident than ever. Currently, insulator (usually SiO2) growth and deposition contribute significantly to the total thermal budget, and it is clear that this will have to be reduced in future processes. In addition, many other applications require the deposition of high quality dielectrics at very low substrate temperatures, typically ≳ 350°C. Plasma-enhanced chemical vapor deposition (PECVD) is a technique which can be used to deposit insulators at suitably low temperatures, although it tends to produce SiO2 which exhibits poor electrical and physical properties and which forms poor interfaces with semiconductor substrates. Direct exposure to the high energy environment of the plasma is generally thought to be the main reason for this.

scholarly journals Vertical Graphene Arrays for AC Line-Filtering Capacitors

2021 ◽  
Author(s):  
Jin Zhang ◽  
Shichen Xu ◽  
Yeye Wen ◽  
Zhuo Chen ◽  
Nannan Ji ◽  
...  
Keyword(s):  
Energy Density ◽  
High Frequency ◽  
Chemical Vapor ◽  
Electrochemical Capacitor ◽  
High Energy ◽  
High Energy Density ◽  
Electrolytic Capacitor ◽  
Electrode Structure ◽  
Aluminum Electrolytic Capacitor ◽  
High Frequency Response

Abstract High-frequency responsive electrochemical capacitor (EC), which can convert alternating current (AC) in the circuit to direct current (DC), is an ideal filtering capacitor with lightweight superiority to replace the bulky aluminum electrolytic capacitor (AEC). However, current electrodes are difficult to achieve high energy density and high-frequency response properties simultaneously, primarily due to the electrode structure dilemmas of maximizing the electrode area or accelerating the ion transport. Herein, strictly vertical graphene arrays (SVGAs) directly prepared by electric-field-assisted plasma enhanced chemical vapor deposition have been successfully designed as the main electrode material of ECs to ensure the ions rapidly adsorb/desorb within the richly available surface spaces. The SVGAs exhibit an excellent specific areal capacitance of 1.72 mF‧cm− 2 at Φ120 = 80.6° even after 500,000 cycles in the aqueous ECs, which is far better than that of most quasi-vertical electrodes and carbon-related materials. Impressively, the output voltage could also be improved to 2.5 V when using the organic electrolyte, and an ultra-high energy density of 4.75 mF‧V2‧cm− 2 at Φ120 = 80.6° can also be handily achieved. Moreover, both aqueous and organic ECs-SVGAs can well smooth arbitrary AC waveforms into DC signals, indicating that ECs-SVGAs have colossal potentials to replace outmoded AECs.

Molten Salt Synthesized MgNiO2 Micro/Nano-Particles for High Energy Density Supercapacitor and Electrocatalyst for Hydrogen Evolution Reaction in Alkaline Medium

2021 ◽  
Vol 21 (11) ◽  
pp. 5556-5568
Author(s):  
S. Maitra ◽  
R. Mitra ◽  
T. K. Nath
Keyword(s):  
Solid Solution ◽  
Energy Density ◽  
Molten Salt ◽  
Hydrogen Evolution ◽  
Alkaline Medium ◽  
Hydrogen Evolution Reaction ◽  
High Energy ◽  
Nano Particles ◽  
High Energy Density ◽  
Phonon Modes

In recent years, solid solutions have shown promising results as functional materials for different applications. These materials have tunable physiochemical properties and electronic properties, and are being intensively studied for next generation electrochemical charge storage as well as noble metal free low cost electrocatalyts. In the present work, Magnesium Nickel Oxide (MgNiO2) solid solution is prepared by molten salt synthesis. MgNiO2 particles having octahedron shaped morphology with size of 550 nm with an agglomerative behavior was observed through morphological studies. Raman studies revealed presence of three two-phonon modes as well as two one-phonon modes, which confirm the phase purity of MgNiO2 sample. MgNiO2 particles behaved as a promising supercapacitor candidate by exhibiting a large specific capacitance of 76 F/g. It also revealed electrochemical stability over an expansive potential range under the presence of 0.5 mol L-1Sodium Sulfate (Na2SO4) electrolyte, having a high energy density of nearly 51 Wh/kg with a power density of nearly 825 w/kg. Further, MgNiO2 particle showed improved electrocatalytic potential towards Hydrogen Evolution Reaction (HER) in 1 mol L-1 Potassium Hydroxide (KOH) alkaline medium, by demonstrating an overpotential of 0.636 V with a Tafel slope of 0.22205 v/dec. Based on these observed promising results, it can be conclusively inferred that MgNiO2 solid solution is a potential candidate for environmental friendly high voltage supercapacitor and HER electrocatalyst applications.

scholarly journals Design and Preparation of Biomass-Derived Carbon Materials for Supercapacitors: A Review

2018 ◽  
Vol 4 (4) ◽  
pp. 53 ◽  
Author(s):  
Yang Liu ◽  
Jiareng Chen ◽  
Bin Cui ◽  
Pengfei Yin ◽  
Chao Zhang
Keyword(s):  
Chemical Activation ◽  
High Energy ◽  
High Energy Density ◽  
Nanoporous Structure ◽  
Clear Understanding ◽  
Structure Property ◽  
Carbon Yield ◽  
Research Attention ◽  
Elemental Compositions ◽  
Supercapacitor Applications

The synthesis and application of biomass-derived carbon in energy storage have drawn increasing research attention due to the ease of fabrication, cost-effectiveness, and sustainability of the meso/microporous carbon produced from various biological precursors, including plants, fruits, microorganisms, and animals. Compared to the artificial nanostructured carbons, such as fullerene, carbon nanotube and graphene, the biomass-derived carbons may obtain superior capacitance, rate performance and stability in supercapacitor applications ascribing to their intrinsic nanoporous and hierarchical structures. However, challenges remain in processing techniques to obtain biomass-derived carbons with high carbon yield, high energy density, and controllable graphitic microstructures, which may require a clear understanding over the chemical and elemental compositions, and the intrinsic microstructural characteristics of the biological precursors. Herein we present comprehensive analyses over the impacts of the chemical and elemental compositions of the precursors on the carbon yield of the biomass, as well as the mechanism of chemical activation on the nanoporous structure development of the biomass-derived carbons. The structure–property relationship and functional performance of various biomass-derived carbons for supercapacitor applications are also discussed in detail and compared. Finally, useful insights are also provided for the improvements of biomass-derived carbons in supercapacitor applications.

Development Of Diamond Based Power Microelectronics

1997 ◽  
Vol 483 ◽  
Author(s):  
J. L. Davidson ◽  
W. P. Kang ◽  
Y. Gurbuz ◽  
D. V. Kerns ◽  
L. Davis ◽  
...  
Keyword(s):  
Diamond Film ◽  
Schottky Diodes ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
High Energy ◽  
High Energy Density ◽  
Field Emitters ◽  
Device Structures ◽  
Electron Emitters ◽  
Polycrystalline Diamond Film

AbstractDiamond based power device structures such as resistor, capacitor, Schottky diode, p-n diode, thyristor, and field emitters are being investigated. Diamond resistors similar to standard thick film components in form and dimension were fabricated of polycrystalline diamond film. Using PECVD (plasma-enhanced chemical vapor deposition) processing to achieve diamond dielectric layers, high power, high energy density capacitors have been built. Despite grain boundaries and defects of polycrystalline diamond film, electronic devices such as field-effecttransistors and Schottky diodes have been developed. We have fabricated micro-patterned microtip arrays with this versatile new diamond technology as electron emitters. This paper will review diamond technology and results of this work.

Combustion of Boron Nano-Particles in Ethanol Spray Flame

2010 ◽  
Author(s):  
Srinibas Karmakar ◽  
Sumanta Acharya ◽  
Kerry M. Dooley
Keyword(s):  
Energy Density ◽  
Particle Surface ◽  
Combustion Process ◽  
High Energy ◽  
Nano Particles ◽  
High Energy Density ◽  
Particle Analysis ◽  
Fuel Additive ◽  
Hydrocarbon Combustion ◽  
Spray Flame

Biofuels such as ethanol have lower energy density than conventional petroleum-based fuels, and therefore enhancing its energy density via addition of high-energy density components is an attractive option. Boron is an attractive fuel additive because it has among the highest volumetric heating value among potentially suitable additives. The present study deals with an experimental investigation of boron combustion in an ethanol spray flame. A constant low particle loading density of boron nanoparticles (60nm SMD), around 1% (by weight) of the liquid fuel flow rate, has been used. Though it has high energetic potential, the combustion process of boron is retarded by the initial presence of the oxide coating the particle surface. In the present study, measurements have been made of the emission of intermediate sub-oxide like BO2 using spectroscopy and imaging with interference filters. The effect of boron on the hydrocarbon combustion has also been studied by examining the heat release and product mole fractions. In addition, particle characterization has been carried out to know the size, surface structure/composition of the injected boron nano powders using XRD, XPS and TEM. A preliminary investigation has also been performed on the burnt particle collected from the exhaust structure using XRD. The chemiluminescence and spectroscopic signatures indicate that boron combustion is facilitated and that hydrocarbon combustion is enhanced. The particle analysis shows differences in the imaged and spectroscopic characteristics of the unburnt and burnt nano-particles reflecting the particle-combustion processes.

scholarly journals Study of Micro-Silicon Particles Covered by Graphene

2021 ◽  
Vol 3 (3) ◽  
pp. 182-190
Author(s):  
Peilin Yu ◽  
Mingyang Zhang
Keyword(s):  
Lithium Ion Batteries ◽  
Anode Materials ◽  
Hot Spot ◽  
Solid Electrolyte Interphase ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Environmental Friendliness ◽  
The Times ◽  
Silicon Based

Lithium-ion batteries have become a new hot spot in battery research due to their high-energy density, environmental friendliness, and multiple charge/discharge times. Silicon-based materials have become the best choice of anode materials for lithium-ion batteries due to their advantages of low lithium insertion voltage, high specific theoretical capacity, and large reserves on the planet. However, the silicon-based material has a large volume expansion (about 300%) during cycling, which causes the active silicon to fall off from the surface of the conducting material. This expansion will also break the solid electrolyte interphase (SEI) on the surface of the silicon electrode, and will consume additional Li+, causing the battery’s capacity to drop rapidly as the times of circulation increases. In addition, the conductivity of silicon-based materials is lower than that of graphite anode, which have already been used commercially, led to the worse performance of the silicon anode. These drawbacks force silicon-based anode materials to encounter huge resistance in the commercialization process. Therefore, research on the improvement of performance of the silicon-based anode materials is of great significance. 

scholarly journals Influence of Nano Particle Size on Attenuation and Dielectric Properties of Plantain Husk Powder Using Microwave Techniques at X-Band Frequency

2020 ◽  
pp. 41-51
Author(s):  
Abubakar Yakubu ◽  
Zulkifli Abbas ◽  
Olotu Olugbenga ◽  
Suleiman Sahabi
Keyword(s):  
Particle Size ◽  
Dielectric Properties ◽  
Health Hazard ◽  
Milled Powder ◽  
High Energy ◽  
Dielectric Constants ◽  
Nano Particles ◽  
Nano Particle ◽  
Band Frequency ◽  
A Value

Ferrite are conventional materials used for microwave absorption, however, they are expensive, constitute health hazard and pollutes the environment. For these reasons, there is need to explore safe and environmental friendly materials that can serve as radiation absorbers and be used in fabricating microwave devices. In the light of the above, this work was geared towards exploring the use of Unripe Plantain Husk (UPH) waste material for microwave absorber applications. The usability was determined by investigating the dielectric properties and attenuation of the UPH powder with respect to particle size and frequency of operation. The nano particle of the UPH was prepared aseptically by washing in water and acetone, sliced, sundried and grinded. The grinded UPH powder was then subjected to high energy milling using a SPEX 8000D shaker for 4 hours, 8 hours, 10 hours and 12 hours. The milled powder was then prepared into pellets by suppressing with hydraulic press and mold which were then used for characterization. Results from investigation and analysis showed that the milled powder was in nano dimension using transmission electron microscope (TEM). The UPH powder sizes were in the range of 63.35 nm, 52.05 nm, 42.86 nm and 21.43 nm for the 4, 8, 10 and 12 hours milling, respectively. The dielectric constants for the as produced, 4, 8, 10 and 12 hours milled powder were 2.96, 4.97, 5.66, 6.97 and 10.36, respectively. The highest magnitude for attenuation was calculated for the 12 hours milled powder with a value of 14.92 dB and the least attenuation was calculated for the as produced powder with a value of 6.72 dB. Based on the results obtained it is concluded that nano particles of UPH powder is good for microwave attenuation and is a potential for fabricating electronic components.

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