Power and Energy Commons^™

Plasma Treatment Method For Ohmic Contacts On Zinc Oxide Thin Film Transistors, Blaine Z. Underwood

Theses and Dissertations

This research utilizes plasma treatments as a method to decrease the contact resistance on zinc oxide (ZnO) thin film transistors (TFT). In recent years, researchers have achieved gigahertz RF switch cutoff frequency with ZnO TFTs. To further increase the cutoff frequency, the total resistance of this device must be minimized. Modern ZnO TFTs are fabricated with submicron channel lengths, which contains minimal resistance due to the TFT channel, making contact resistance significant to the total resistance of the device. This research developed a method to integrate plasma treatments into the fabrication of ZnO TFT to decrease the contact resistance, thus …

A Systematic Study On The Effects Of Dimensional And Materials Tolerances On Permanent Magnet Synchronous Machines Based On The Ieee Std 1812, Narges Taran, Vandana Rallabandi, Dan M. Ionel, Ping Zhou, Mark Theile, Greg Heins

Power and Energy Institute of Kentucky Faculty Publications

In the process of designing and manufacturing an electrical machine, a systematic study of dimensional and material tolerances is of the utmost importance. This paper proposes a systematic method by which the effect of design specification variations on permanent magnet (PM) synchronous machine performance may be identified and quantified. The method combines design of experiments techniques, open-circuit and short-circuit physical measurements, and virtual test simulations conducted based on the recently approved IEEE Std 1812 testing guide. Three case studies, two provided by a spoke-type PM radial field machine configuration, in two designs with different electromagnetic loading, and an axial flux …

Microgrid Renewable Energy Integration, Do Quang Thanh Vo

Electrical Engineering

The Microgrid is a small-scale electrical system that is designed to give Cal Poly students hands-on experience on power generation, system protection, distribution, and automation that would otherwise be very difficult to experiment in a large-scale model.

To closely replicate the modern electrical grid, a renewable energy source shall be added to the Microgrid in conjunction with the existing synchronous generators. Electrical engineering student, Virginia Yan initiated this effort, namely Grid-Tied Solar System project [1], by designing and constructing a set of solar panels and microinverter for future connection to the Microgrid. The scope of Virginia’s project was, however, limited …

36% Reduction In Fuel Resupply Using A Hybrid Generator & Battery System For An Austere Location, David J. Chester, Torrey J. Wagner, Douglas S. Dudis

Faculty Publications

The DOD energy policy is to increase energy security resiliency, and mitigate costs in the use and management of energy^[1] Forward operating bases (FOBs) are remote, austere base camps that support an operationally defined mission with a limited or no ability to draw from an energy grid and have historically relied on diesel-powered generators for the primary production of energy.^[2] Generators are sized to meet a theoretical peak demand, but steady state loads are far below this peak, resulting in under-loaded generators.^[3] Under-loaded diesel generators decrease efficiency and increase the need for maintenance, affecting the lifespan of …

Current Status And Prospect Of Battery Configuration In Li-S System, Jia-Hang Chen, Hui-Jun Yang, Cheng Guo, Jiu-Lin Wang

Journal of Electrochemistry

Commercial lithium-ion batteries (LIBs) are incapable of satisfying the increasing demand for emerging electronic devices due to their limited energy density. Among the next-generation batteries, lithium-sulfur (Li-S) batteries are becoming a promising energy-storage system due to their high theoretical energy density and natural abundance of sulfur. However, the shuttle of soluble polysulfide intermediates between two electrodes, as well as the problem on Li metal anode,lower the utilization of active material and lead to the loss of specific capacity and rapid capacity fading. All the above challenges limit the further application of Li-S batteries. Recently, various novel battery configurations have been …

Recent Progress On Tio2-Based Anode Materials For Sodium-Ion Batteries, Si-Tian Lian, Jian-Shuai Lv, Qiang Yu, Guang-Wu Hu, Zhuo Chen, Liang Zhou, Li-Qiang Mai

Journal of Electrochemistry

Titanium dioxide (TiO₂) represents a stable, low-cost, and nontoxic anode material for sodium-ion batteries (SIBs). However, the low electrical conductivity limits its electrochemical activity (specific capacity) and rate capability, hindering its widespread applications. In this article, we show that different crystal forms of TiO₂ have different pore structures, resulting in the distinct sodium storage capacities. Accordingly, the article introduces how TiO₂ microstructures influence sodium storage. The nanoparticle structure can improve the rate performance of the material due to its short ion diffusion distance, and the internal cavity of the hollow structure is beneficial to cycle stability. …

Recent Progress In Key Materials For Room-Temperature Sodium-Ion Batteries, Fan-Fan Wang, Xiao-Bin Liu, Long Chen, Cheng-Cheng Chen, Yong-Chang Liu, Li-Zhen Fan

Journal of Electrochemistry

Sodium-ion batteries (SIBs) have attracted tremendous attention in large-scale energy storage applications due to their resource advantages. However, Na+ is larger and heavier than Li+, which will limit its reversible reaction with the electrode materials and result in poor electrochemical performance. Thus, developing stable and high-efficiency electrode materials is the key to promoting the practical application of SIBs. Furthermore, the optimization of electrolyte is essential for the construction of high-safety and long-lifespan SIBs. In this review, we mainly summarize the recent advancements of electrode materials and electrolytes for room-temperature SIBs and discuss their challenges and possible resolution strategies. We hope …

Recent Developments In Surface/Interface Modulation And Structure-Performance Relationship Of Cathode Catalysts For Li-Air Batteries, Rui Gao, Jun-Kai Wang, Zhong-Bo Hu, Xiang-Feng Liu

Journal of Electrochemistry

Lithium-air battery has been considered to be one of the most promising secondary battery systems because of its high energy density. However, the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the cathode, and the high overpotential, poor cycle stability and low rate capacity have severely blocked the development and application of Li-air battery. One of the effective strategies to alleviate these issues is to develop cathode catalysts for Li-air batteries. The design and development of bifunctional cathode catalysts with high activity and efficiency on both ORR and OER is highly desired for Li-air …

A Comparative Study Of Pre-Lithiated Hard Carbon And Soft Carbon As Anodes For Lithium-Ion Capacitors, Zhao Li, Xian-Zhong Sun, Wen-Jie Liu, Xiong Zhang, Kai Wang, Yan-Wei Ma

Journal of Electrochemistry

Lithium-ion capacitor (LIC) has emerged to be one of the most promising electrochemical energy storage devices. Presently, activated carbon (AC) is the mostly used cathode material for LIC. Nevertheless, various carbonaceous materials can be used as anode materials, such as hard carbon (HC) and soft carbon (SC). Therefore, HC and SC with different structural and electrochemical characteristics have been investigated as the anode materials of LICs in this work. Compared with the HC electrode, the SC electrode showed higher electronic conductivity and reversible capacity. The rate capabilities of the two carbonaceous materials as a function of coating thickness have been …

Cvd Preparation And Application Of 3d Graphene In Electrochemical Energy Storage, Yong-Kang Xia, Ming-Yuan Gu, Hong-Guan Yang, Xin-Zhi Yu, Bing-An Lu

Journal of Electrochemistry

Three-dimensional (3D) graphene combinations with the excellent intrinsic properties of graphene and the 3D micro/nano porous structures provide a graphene foam with high specific surface area, excellent mechanical strength and fast electron and mass transports. The 3D graphene foam and its composite nanomaterials are widely used in the fields of nano-electronics, energy storage, chemical and biological sensing. The 3D graphene foam prepared by chemical vapor deposition (CVD) method is of high purity and crystallinity.  In this review, a brief overview in the CVD preparations of 3D graphene and properties of CVD prepared 3D graphene based nanomaterials in electrochemical energy storage …

Applications Of Advanced Imaging Technologies For Critical Issues Of All-Solid-State Lithium Battery Studies, Yi-Bo Zhao, Hui-Hui Liu, Song-Liang Chen, Shou-Hang Bo

Journal of Electrochemistry

All-solid-state lithium batteries have attracted much attention for their high energy density and good safety. To increase their efficiency and prolong their service life, it is necessary to achieve high ion conductivity at the electrode/electrolyte interface and in the electrolyte, as well as to eliminate dendrites growth in the battery. Based on the critical requirements outlined above, this paper discusses the applications of advanced imaging technologies in relevant studies. Recent progresses in investigations of all-solid-state lithium batteries by imaging techniques including electron microscopy, scanning probe microscopy, X-ray tomography, magnetic resonance imaging and optical microscopy are summarized.

Synthesis Of Flower-Like Vanadium Disulfide For Lithium Storage Application, Pan Li, Jian Liu, Wei-Yi Sun, Hai-Xia Li, Zhan-Liang Tao

Journal of Electrochemistry

In order to improve the electrochemical properties of vanadium disulfide (VS₂) as an electrode material in Li-ion battery, the flower-like VS₂ was prepared by a one-step hydrothermal method with the addition of polyethylene glycol 400. The phase and morphology of the product were characterized by using X-ray diffraction and field emission scanning electron microscopy. During the growth process, it was observed that the flower-like VS₂ was interspersed with several hexagonal vanadium disulfide nanosheets, which had a high specific surface area and excellent structural stability. The flower-like VS₂ was used for the cathode material test in …

Ni/Mn3O4/Nimn2O4 Double-Shelled Hollow Spheres Embedded Into Reduced Graphene Oxide As Advanced Anodes For Sodium-Ion Batteries, Chong Yan, Hua-Ri Kou, Bo Yan, Xiao-Jing Liu, De-Jun Li, Xi-Fei Li

Journal of Electrochemistry

Delicately building the unique nanocomposite with the combination of hollow structure and reduced graphene oxide (rGO) is highly desirable and still remains a great challenge in the field of energy conversion and storage. In this work, Ni/Mn₃O₄/NiMn₂O₄ double-shelled hollow spheres coated by rGO (denoted as R-NMN) have been successfully synthetized via one-step rapid solvothermal treatment followed by subsequent annealing for the first time. Served as anodes for sodium ion batteries (SIBs), the R-NMN composite containing 25wt% rGO exhibits a high discharge capacity of 187.8 mAh·g^-1 after 100 cycles at 50 mA·g^{-1 …}

Preface On Special Issue Of Next-Generation Secondary Batteries, Zhen Zhou, Quan-Feng Dong

Journal of Electrochemistry

No abstract provided.

Surface And Interface Properties In Thin-Film Solar Cells: Using Soft X-Rays And Electrons To Unravel The Electronic And Chemical Structure, Lothar Weinhardt, Dirk Hauschild, Clemens Heske

Chemistry and Biochemistry Faculty Research

Thin‐film solar cells have great potential to overtake the currently dominant silicon‐based solar cell technologies in a strongly growing market. Such thin‐film devices consist of a multilayer structure, for which charge‐carrier transport across interfaces plays a crucial role in minimizing the associated recombination losses and achieving high solar conversion efficiencies. Further development can strongly profit from a high‐level characterization that gives a local, electronic, and chemical picture of the interface properties, which allows for an insight‐driven optimization. Herein, the authors' recent progress of applying a “toolbox” of high‐level laboratory‐ and synchrotron‐based electron and soft X‐ray spectroscopies to characterize the chemical …

Improving The Energy Efficiency Of Petrochemical Plant Operations: A Measurement And Verification Case Study Using A Balanced Wave Optimizer, Man Hin Eve Chan, Kar-Kit Chu, Hin-Fung Chow, Chi-Wing Tsang, Chi Kuen Danny Ho, Shuk-Kei Ho

Faculty of Design & Environment (THEi)

The Chinese petrochemical industry is facing pressure to meet strict targets of energy consumption and carbon emission reductions. Water pumps are the primary equipment used in most chemical and agrochemical industries sectors since water is commonly used for cooling and heating purposes, but these pumps also consume a large amount of energy. Other uses of water pumps in these industries include producing steam for heating, preparing reaction media or absorptive reagents, rinsing products, and distilling. As for the electrical components of the water pump systems, current technologies of variable frequency drives and superconducting transmission lines are unable to increase the …

Control Strategy For A Small-Scale Microgrid Based On Battery Energy Storage System-Virtual Synchronous Generator (Bess-Vsg), Wei Gao

Electronic Theses and Dissertations

As one of widely deployed renewable energy resources, PV power is playing a very important role in microgrids today. It has advantages such as making the best of natural solar energy and being friendly to our environment. In this thesis, solar PV based microgrid is studied using modeling and simulation. Microgrid can run in either grid-connected-mode or islanded-mode. However, there are also some disadvantages for solar power. For solar panel, its output is influenced by weather conditions such as illumination intensity and temperature. In addition, during the control process of grid-connected mode, it is hard to guarantee its output power …

Solar Forecasting And Integration In Power Systems, Mohana Alanazi

Electronic Theses and Dissertations

Renewable energy resources are becoming critical players in the electricity generation sector, primarily due to viability in combating global warming, effectiveness in reducing pollution caused by fossil fuel based generation, and diversifying energy mix to ensure energy security and sustainability. Solar energy is one of the most common types of renewable energy that has grown rapidly over the past decade and is anticipated to grow even faster in the future. Power supply from renewable resources is forecasted to surpass other types of generation in a foreseeable future. Numerous factors, including but not limited to the dropping cost of solar technology, …

A Study On Distributed Generation With A Focus On Solar Power, Shravan Kumar Tomar

Electronic Theses and Dissertations

Centralized generation is when electric power is produced in a large scale of tens of MWs and is located away from the end user. This kind of production is connected to a series of high-voltage transmission lines. Electricity is then delivered to the end user through a network of distribution grids. Centralized generation tend to have multiple end user with multiple user profiles.

Distributed Generation is when is produced in a small scale and is located at the site of or very close to the end user. There are many ways distributed generation can be achieved, Solar power being the …

Design And Analysis Of A Non-Isolated High Gain Step-Up Cuk Converter, Yasser Almalaq

Electronic Theses and Dissertations

Renewable energy sources, such as solar energy, are desired for both economic and ecological issues. These renewable energy sources are plentiful in nature and have a terrific capability for power generation. The only drawback of solar energy, which is one of the best forms of energy sources, is that the output has a low voltage and needs to be stepped up in order to be inserted into the DC grid or an inverter for AC applications. To overcome this drawback, a high gain DC-DC power converter is required in this kind of system. These power converters are needed for a …