Materials Science and Engineering Commons^™

Experimental Optimization Of Simulated Ring Rolling Operation For Heavy Rail Industry, Jacob M. Summers

Masters Theses

“Industrially cast AISI 1070 steel wheel pre-forms from Amsted Rail Co. were experimentally hot rolled to simulate the conditions for industrial wheel rolling. Ring rolling of near net shape castings can improve location specific properties by decreasing segregation, closing porosity, and reducing grain size without the use of multiple forging operations in a traditional forging line. As-cast wheel sections were subjected to thermomechanical processing routes using a 2-high rolling mill in a temperature range of 830°C to 1200°C. The goal being to simulate the ring rolling process and optimize benefits of mechanical properties of the as-rolled steel. Charpy V- and …

การเตรียมและการวิเคราะห์ลักษณะสมบัติผ้าไหมที่เคลือบผิวด้วยไคโตซาน/ซิลเวอร์/มอนต์มอริลโลไนต์คอมโพสิต, ลักษณารีย์ มาละ

Chulalongkorn University Theses and Dissertations (Chula ETD)

งานวิจัยนี้ศึกษาการเคลือบผิวผ้าไหมด้วยไคโตซาน/ซิลเวอร์/มอนต์มอริลโลไนต์คอมโพสิต โดยซิลเวอร์คอลลอยด์ถูกสังเคราะห์ด้วยกระบวนการรีดักชันทางเคมี และกระบวนการรีดักชันด้วยแสงยูวี ผลการศึกษาพบว่าภาวะที่เหมาะสมสำหรับการเคลือบซิลเวอร์คอลลอยด์สีน้ำเงินที่เตรียมด้วยวิธีรีดักชันทางเคมี โดยใช้โซเดียมโบโรไฮไดรด์ (NaBH4) เป็นตัวรีดิวซ์ (ความเข้มข้นของซิลเวอร์ไนเตรต 0.2 มิลลิโมลาร์) บนผ้าไหมอย่างสมบูรณ์ด้วยกระบวนการจุ่มแช่และกวน โดยใช้อัตราส่วนโดยน้ำหนักของซิลเวอร์คอลลอยด์ : น้ำหนักผ้าไหม เท่ากับ 1 : 200 คือ ที่อุณหภูมิในการเคลือบ 100 องศาเซลเซียส เป็นเวลา 90 นาที โดยซิลเวอร์คอลลอยด์ถูกปรับค่าความเป็นกรด-ด่าง เท่ากับ 5 ด้วยกรดแอซิติก ซึ่งผ้าไหมที่ถูกเคลือบด้วยซิลเวอร์คอลลอยด์และไคโตซานแสดงสมบัติการต้านแบคทีเรียชนิด S. aureous ได้ดีเยี่ยม และเมื่อนำไปเคลือบทับด้วยมอนต์มอริลโลไนต์ด้วยกระบวนการบีบอัดโดยใช้เครื่องบีบอัด พบว่าช่วยเพิ่มสมบัติการหน่วงไฟให้กับผ้าไหม แต่สมบัติการต้านแบคทีเรียลดลง การสังเคราะห์ซิลเวอร์คอลลอยด์โดยวิธีรีดักชันด้วยแสงยูวี โดยการฉายแสงยูวีบนสารละลายซิลเวอร์ไนเตรตที่เตรียมร่วมกับไคโตซาน พบว่าที่เวลา 2 ชั่วโมง เป็นเวลาที่เหมาะสมที่สุดในการเตรียม ซึ่งแสดงสเปกตรัมการดูดกลืนแสงที่แสดงสมบัติ Localized surface plasmon resonance (LSPR) บ่งชี้การเกิดอนุภาคซิลเวอร์นาโนหลังการฉายแสงยูวี และเมื่อนำไปวิเคราะห์โครงสร้างจุลภาค พบการกระจายของอนุภาคซิลเวอร์นาโนบนพื้นผิวของผ้าไหม หลังจากนั้นนำไปเตรียมเป็นคอมโพสิตร่วมกับมอนต์มอริลโลไนต์ และเคลือบบนผ้าไหมด้วยกระบวนการบีบอัดโดยใช้เครื่องบีบอัด พบว่าผ้าไหมที่ผ่านการเคลือบด้วยไคโตซาน/ซิลเวอร์ และไคโตซาน/ ซิลเวอร์/มอนต์มอริลโลไนต์คอมโพสิต ด้วยการรีดิวซ์ด้วยแสงยูวี ให้ผลการทดสอบสมบัติการต้านแบคทีเรียและการหน่วงไฟในทำนองเดียวกันกับวิธีรีดักชันทางเคมี

Synthesis Of Novel Nio/Comn2o4 Heterostructured Nanoparticles And The Effects Of Variable Size And Metal Concentrations On Their Magnetic And Surface Chemical Properties, Farhan Ishrak

Graduate Theses/Dissertations

I studied the effect of core size and metal concentration on the structural, morphological, and magnetic properties of NiO-based magnetic heterostructured nanocrystals (HNCs) generated hydrothermally. The NiO nanocrystals were created by a thermal decomposition technique, while the surrounding Mn and Co-based phases were created through a hydrothermal procedure, with core diameters ranging from 9.31 nm to 24.51 nm and total metal concentrations of 0.05 M and 0.08 M. The resulting inverted AFM-FiM NiO/CoMn2O4 bimagnetic systems make up the heterostructured nanocrystals. The magnetic HNCs were thoroughly characterized using XRD, SEM-EDX, TEM, PPMS magnetometry, and XPS analysis. Investigations into the structure of …

3d Printing And Shape Memory Of Silicone Acrylate Polymers, Aphiwat Pongwisuthiruchte

Chulalongkorn University Theses and Dissertations (Chula ETD)

The purpose of this research is to develop a novel UV curable resin as a 3D printing material which possesses shape memory properties. The first part of the study focuses on formulating acrylate-based resins by combining low-cost polypropylene glycol (PPG) with a commercial acrylate-based resin. The effects of PPG content on the printability, thermal, mechanical, and thermomechanical properties of the formulated resins were studied. The results show that the mechanical properties of the printed parts were successfully enhanced at a small loading of 5%vol. However, a higher PPG content leads to printing failure and reduced mechanical properties. The degree of …

Lateral-Torsional Instability And Biaxial Bending Of Imperfect Frp I-Beams, Jodi Knorowski, Stella B. Bondi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents the outcome of a theoretical and experimental study of the behavior of Fiber Reinforced Polymer (FRP) I-beams exposed to lateral-torsional instability or when subjected to biaxial bending. Laboratory experiments involved the application of vertical and horizontal static loads to a 4 x 4 x ¼ in. I-beam with various lengths and the resulting deflections were recorded. Governing biaxial flexure and torsion differential equations were modified to account for the presence of initial imperfections and subsequently solved using a central finite-difference scheme. The theoretical predictions of the beam behavior were found to be in good agreement with what …

Exploring The Effects Of Chip Flexibility On The Behavior Of Standing Seam Diaphragms To Brace Cold Formed Steel Purlins, Michael W. Seek

Engineering Technology Faculty Publications

Cold-formed steel C- and Z-shaped purlins in standing seam roof systems rely on the diaphragm action provided by the panels to restrain lateral movements and thus increase the load carrying capacity the purlins. The clip connection between the purlin and the panel has inherent and sometimes intentional flexibility designed to accommodate thermal deformations. The lateral deformation behavior of standing seam systems supported by Zees is highly nonlinear and this behavior is not well understood. The flexibility has major implications on the transfer of diaphragm forces throughout these systems and simplified models often grossly overpredict the demands on the diaphragm and …

Broadband Dielectric Spectroscopic Detection Of Ethanol: A Side-By-Side Comparison Of Zno And Hkust-1 Mofs As Sensing Media, Papa K. Amoah, Zeinab Mohammed Hassan, Pengtao Lin, Engelbert Redel, Helmut Baumgart, Yaw S. Obeng

Electrical & Computer Engineering Faculty Publications

The most common gas sensors are based on chemically induced changes in electrical resistivity and necessarily involve making imperfect electrical contacts to the sensing materials, which introduce errors into the measurements. We leverage thermal- and chemical-induced changes in microwave propagation characteristics (i.e., S-parameters) to compare ZnO and surface-anchored metal-organic-framework (HKUST-1 MOF) thin films as sensing materials for detecting ethanol vapor, a typical volatile organic compound (VOC), at low temperatures. We show that the microwave propagation technique can detect ethanol at relatively low temperatures (<100 >°C), and afford new mechanistic insights that are inaccessible with the traditional dc-resistance-based measurements. In addition, …

Solution Atomic Layer Deposition Of Smooth, Continuous, Crystalline Metal-Organic Framework Thin Films, Maïssa K.S. Barr, Soheila Nadiri, Dong-Hui Chen, Peter G. Weidler, Sebastian Bochmann, Helmut Baumgart, Julien Bachmann, Engelbert Redel

Electrical & Computer Engineering Faculty Publications

For the first time, a procedure has been established for the growth of surface-anchored metal–organic framework (SURMOF) copper(II) benzene-1,4-dicarboxylate (Cu-BDC) thin films of thickness control with single molecule accuracy. For this, we exploit the novel method solution atomic layer deposition (sALD). The sALD growth rate has been determined at 4.5 Å per cycle. The compact and dense SURMOF films grown at room temperature by sALD possess a vastly superior film thickness uniformity than those deposited by conventional solution-based techniques, such as dipping and spraying while featuring clear crystallinity from 100 nm thickness. The highly controlled layer-by-layer growth mechanism of sALD …

Method For Reducing Warping Stresses In Torsionally Loaded I-Section Members Using Cfrp Plates, Mamadou Konate, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents a method for reducing warping normal stresses in torsionally loaded I-section members by utilizing carbon fiber-reinforced polymer (CFRP) plates. The CFRP plates are bonded to the outer surfaces of the flanges with a view to reducing warping normal stresses. The maximum warping normal stress in the flanges of a steel I-shaped member without the CFRP plates is compared to those obtained with the CFRP plates having various thicknesses. It has been found that the use of CFRP plates bonded to both flanges of the I-section result in a substantial reduction of the warping stresses. For the study …

Reducing Print Time While Minimizing Loss In Mechanical Properties In Consumer Fdm Parts, Long Le, Mitchel A. Rabsatt, Hamid Eisazadeh, Mona Torabizadeh

Mechanical & Aerospace Engineering Faculty Publications

Fused deposition modeling (FDM), one of various additive manufacturing (AM) technologies, offers a useful and accessible tool for prototyping and manufacturing small volume functional parts. Polylactic acid (PLA) is among the commonly used materials for this process. This study explores the mechanical properties and print time of additively manufactured PLA with consideration to various process parameters. The objective of this study is to optimize the process parameters for the fastest print time possible while minimizing the loss in ultimate strength. Design of experiments (DOE) was employed using a split-plot design with five factors. Analysis of variance (ANOVA) was employed to …

Assembly Of Alumina Particles In Aqueous Suspensions Induced By High‐Frequency Ac Electric Field, James E. John, Shizhi Qian, Dipankar Ghosh

Mechanical & Aerospace Engineering Faculty Publications

The role of high-frequency alternating current (AC) electric field in the assembly of alumina particles in aqueous media was investigated. Field–particle interactions were in situ investigated for coarse and fine powder particles in very dilute suspensions. For both coarse and fine particles, AC field-induced assembly led to the formation of chains of particles within a minute, which were aligned in the field direction. However, a much finer network of particle chains evolved in fine particle suspensions. Threshold field strength for chain formation was also lower for fine particles (28 V/mm) than for coarse particles (50 V/mm), suggesting stronger interactions for …

Spray Deposition Of Sustainable Plant Based Graphene In Thermosetting Carbon Fiber Laminates For Mechanical, Thermal, And Electrical Properties, Daniel W. Mulqueen, Siavash Sattar, Thienan Le, Oleksandr G. Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

Graphene has generated substantial interest as a filler due to its exceptional strength, flexibility, and conductivity but faces obstacles in supply and implementation. A renewable, plant-based graphene nanoparticle (pGNP) presents a more accessible filler with the same properties as mineral graphenes. In this study, we examine the effects of pGNP, which was sprayed on a carbon fiber/epoxy prepreg at loadings from 1.1 to 4.2 g/m². The study considered the mechanical, thermal, and electrical properties of pGNP-composite. An even particle dispersion was achieved using a spray application of pGNP in a water/alcohol suspension with the addition of surfactants and …

Hydrophobically Modified Isosorbide Dimethacrylates As Biomaterials For Bisphenol A Free Dental Fillings, Bilal Marie

Dissertations

Amalgam and Bisphenol A glycerolate dimethacrylate (BisGMA) are the main dental filling materials in use today. Because of the negative perception of amalgam and its lower esthetic appeal, as well as the desire to replace the endocrine disruptor Bisphenol A, which is the building block of BisGMA, there has been a critical need to search for safer alternatives to these dental filling materials.

Isosorbide is a sugar-based molecule generally recognized as safe. It has been extensively studied as a replacement to the Bisphenol A core in various materials. However, isosorbide is extremely hygroscopic, and water uptake in dental fillings causes …

Electro-Chemo-Mechanics Of The Interfaces In 2d-3d Heterostructure Electrodes, Vidushi Sharma

Dissertations

Unique heterostructure electrodes comprising two-dimensional (2D) materials and bulk three dimensional (3D) high-performance active electrodes are recently synthesized and experimentally tested for their electrochemical performance in metal-ion batteries. Such electrodes exhibit long cycle life while they also retain high-capacity inherent to the active electrode. The role of 2D material is to provide a supportive mesh that allows buffer space for volume expansions upon ion intercalation in the active material and establishes a continuous electronic contact. Therefore, the binding strength between both materials is crucial for the success of such electrodes. Furthermore, battery cycles may bring about phase transformations in the …

Experimental And Computational Studies Of Functionalized Carbon Nanotubes For Use In Energy Storage Devices And Membranes, Emine S. Karaman

Dissertations

Electrolytes with good interfacial stability are a crucial component of any electrochemical device. The development of novel gel polymer electrolytes (GEs) with good interface stability and better manufacturability is important for the development of the next generation electrochemical devices. Gel electrolytes are hybrid electrolyte materials, combining benefits of both liquid and solid systems. Compared with liquid and solid electrolytes, GEs open new design opportunities and do not require rigorous encapsulation methods. In this dissertation, studies on functionalized carbon nanotubes (fCNTs) and graphene oxide (GO) doped polyvinyl alcohol (PVA) based gel electrolytes (GEs) are reported. The ionic conductivity and mechanical strength …

Electric-Field-Driven Processes In Multiphase Fluid Systems, Qian Lei

Dissertations

Advantages of using electric fields in miniaturized apparatuses for a wide range of applications are revealed by numerous experimental and theoretical studies over the last several decades as it offers a simple and efficient method for manipulation of multiphase fluid systems. This approach is considered to be especially beneficial for control of boiling processes and colloidal suspensions considered in the presented work.

Boiling. Today's trends for enhancing boiling heat transfer in terrestrial and space applications focus on removal of bubbles to prevent formation of a vapor layer over the surface at a high overheat. In contrast, this dissertation presents a …

Flexible Microfluidic Device With Nonplanar Interdigitated Microelectrodes, Saud Alssaidy

Theses

The lab-on-a-chip concept has improved significantly in recent years to meet global demand for various applications with the advent of new technologies. Much progress has been achieved, but many microfluidic devices still suffer from design limitations in terms of sensitivity and selectivity because they use rigid, fragile substrate materials and conventional electrodes, which do not provide high sensitivity or selectivity and suffer from signal-to-noise ratio issues. This work proposes a novel device architecture that uses flexible, transparent top and bottom layers integrated with (nonplanar interdigitated microelectrodes) to create a sandwich-like flexible substrate base. The top and bottom layers consist of …

Critical Analysis Of Material Consumption And Cost Reduction Techniques For The Apparel Cutting Processes, Ismael Taifa, Ibrahim Twaha, Mboka A Mwakibambo

Tanzania Journal of Science

Revenues generation in the garment industry is synonymous with material consumption. This study thus analysed material consumption and cost reduction techniques in the Tanzanian garment industry. The research employed quantitative (experimentation) and qualitative approaches (document review and observation technique) in the apparel cutting processes. Experimental results of material consumption from ten tests averaged efficiency of 78.67%, the wasted pieces (19.2%), and unnoticed waste (2.03%). Essential considerations to reduce material waste include: digitalising the fabric cutting processes; providing workers training; deploying appropriate practices in the cutting room (e.g. pattern engineering and pattern accuracy); considering the quality of the procured fabric and …

New Type Of Lightweight Aggregate For Use In Structural Concrete, Jamal Khatib, Ali Jahami, Oussama Baalbaki, Adel Elkordi

BAU Journal - Science and Technology

This research studied the utilization of municipal solid waste incineration bottom ash (MSWI-BA) in lightweight coarse aggregate (LWC) production. A special method was followed to prepare the new aggregate to fully replace the normal aggregates (NWA) in concrete. The mechanical properties such as compressive strength, tensile strength, and elasticity modulus were investigated for the LWC concrete. Then, two beams were prepared; one from LWC and the other from NWC. The structural performance of beams made up of lightweight aggregates compared to normal aggregates was investigated. The results showed that this type of aggregates led to a 20% reduction in concrete …

Numerical Investigation On The Effect Of Spectral Radiative Heat Transfer Within An Ablative Material, Raghava S. C. Davuluri, Rui Fu, Kaveh A. Tagavi, Alexandre Martin

Mechanical Engineering Faculty Publications

The spectral radiative heat flux could impact the material response. In order to evaluate it, a coupling scheme between KATS - MR and P1 approximation model of radiation transfer equation (RTE) is constructed and used. A Band model is developed that divides the spectral domain into small bands of unequal widths. Two verification studies are conducted: one by comparing the simulation computed by the Band model with pure conduction results and the other by comparing with similar models of RTE. The comparative results from the verification studies indicate that the Band model is computationally efficient and can be used to …

A Comparison Of Solid Electrolyte Interphase Formation And Evolution On Highly Oriented Pyrolytic And Disordered Graphite Negative Electrodes In Lithium-Ion Batteries, Haoyu Zhu, Joshua A. Russell, Zongtang Fang, Pete Barnes, Lan Li, Corey M. Efaw, Allison Muenzer, Jeremy May, Kailash Hamal, I. Francis Cheng, Paul H. Davis, Eric J. Dufek, Hui Xiong

Materials Science and Engineering Faculty Publications and Presentations

The presence and stability of solid electrolyte interphase (SEI) on graphitic electrodes is vital to the performance of lithium-ion batteries (LIBs). However, the formation and evolution of SEI remain the least understood area in LIBs due to its dynamic nature, complexity in chemical composition, heterogeneity in morphology, as well as lack of reliable in situ/operando techniques for accurate characterization. In addition, chemical composition and morphology of SEI are not only affected by the choice of electrolyte, but also by the nature of the electrode surface. While introduction of defects into graphitic electrodes has promoted their electrochemical properties, how such structural …

Cyclic Voltammetric Simulations On Batteries With Porous Electrodes, Xue-Fan Cai, Sheng Sun

Journal of Electrochemistry

Lithium-ion batteries (LIBs) are among the most widely used energy storage devices. Whole-cell modeling and simulations of LIBs can optimize the design of batteries with lower costs and higher speeds. The Pseudo-Two-Dimensional (P2D) electrochemical model is among the most famous whole-cell models and widely applied in LIB simulations. P2D model consists of a series of kinetic equations to model Li⁺/Li diffusion in working/counter electrodes and electrolytes, which are filled in the porous electrodes and separator, and reactions at the interface of electrolyte and active particles. The traditional applications of P2D model, however, are limited to the cases where …

Effect Of Aluminum Alloy Surface Modification On Adhesion Of The Modified Polyurethane Coating And Its Corrosion Protective Performance, Xian-Yin Kuang, Shao-Qiang Jin, Yan-Hui Cao, Yan-Mei Zhang, Shi-Gang Dong, Long-Hui Zhu, Li-Wen Lin, Chang-Jian Lin

Journal of Electrochemistry

The ordinary organic coatings on aluminum alloy usually encounter a problem of low adhesion to the substrate, which results in destruction and failure of the long-term protective performance of the anticorrosion systems. The surface modification of aluminum alloy is able to enhance the adhesion of organic coating on aluminum alloys, and to improve their protective performance. In this work, a combined surface modification of anodic oxidation and mussel adhesion protein/CeO₂/3-aminopropyltriethoxysilane composite film (MCA) was developed on the aluminum alloy. The adhesion of modified polyurethane coated on the treated aluminum alloy and its corrosion protective performance were evaluated comprehensively …

Influence Of Heat Treatment Time On Cathode Material Cr8O21 For Lithium Battery, Jiu-Kang Teng, Qing-Jie Wang, Liang Zhang, Hong-Mei Zhang, Xiao-Tao Chen, Peng Zhang, Jin-Bao Zhao

Journal of Electrochemistry

Chromium oxide (Cr₈O₂₁) cathode material for lithium batteries was synthesized by thermal decomposition of chromium trioxide (CrO₃) at high temperature. The electrochemical properties of chromium oxide depended on the time and temperature during the heat treatment. Pure phase chromium oxide was prepared, and the effects of heat treatment time on the structures and electrochemical properties of Cr₈O₂₁ were systematically studied. The first discharge mechanism of chromium oxide in lithium batteries was explored, and the results were similar to that in lithium-sulfur batteries. The crystal phases and electrochemical properties of the prepared …

Effect Of Glycol Based Coolant Pollution On Pem Fuel Cells Stack And Recovery Measures, Cong-Yi Zhu, Xiao-Hui Li, Quan-Quan Gan

Journal of Electrochemistry

As the heat conduction medium of fuel cell cooling system, coolant is very important for the thermal management of fuel cell stack. In practical application, coolant leakage into the stack often occurs. Due to the randomness of fault location of components, the location of coolant leakage is uncertain, which may occur on the cathode side or anode side of some or all single cells. The main effects of coolant pollution on fuel cell stack are as follows: the output of open circuit voltage decreases sharply, the consistency of single cells voltage decreases and so on, which seriously affects the normal …

Copper Nanoparticles In-Situ Anchored On Nitrogen-Doped Carbon For High-Efficiency Oxygen Reduction Reaction Electrocatalyst, Hui-Fang Yuan, Yue Zhang, Xing-Wu Zhai, Li-Bing Hu, Gui-Xian Ge, Gang Wang, Feng Yu, Bin Dai

Journal of Electrochemistry

Compared with noble metal platinum (Pt)-based catalysts, inexpensive non-noble metal electrocatalysts have attracted extensive attention for oxygen reduction reaction (ORR). Herein, chitosan as a kind of biomass resource rich in nitrogen and carbon was used to prepare nitrogen-doped carbon (N-C) and N-C in-situ anchored by copper nanoparticles (Cu/N-C). The as-obtained N-C and Cu/N-C nanoparticles were successfully used as non-noble eletrocatalysts tested for ORR. Compared with the N-C, the Cu/N-C showed the high surface area of 607.3 m ²·g^-1 with the mean pore size of 2.5 nm and the pore volume of 0.40 cm³·g^{-1 …}

Photoelectrochemical Sensing Based On Zr-Mofs For Homocysteine Detection, Wen-Xia Dong, Guang-Ming Wen, Bin Liu, Zhong-Ping Li

Journal of Electrochemistry

Due to the independent form of the light source and detection system, photoelectrochemical (PEC) sensor has the advantages of low background, high sensitivity and simple operation. So far, PEC systems have been widely used in the fields including the actual detection of metal ions, biological antibodies or antigens in environmental pollutants. When the photosensitive material is irradiated by a light source with an energy being equal to or greater than its band gap, electrons (e^-) transition occurs from the valence band to the conduction band, leaving a hole (h⁺), at the same time, the generated electron-hole …

Functional Sulfate Electrolytes Enable The Enhanced Cycling Stability Of Nati2(Po4)3/C Anode Material For Aqueous Sodium-Ion Batteries, Shu-Jin Li, Zhi-Kang Cao, Wen-Kai Wang, Xiao-Han Zhang, Xing-De Xiang

Journal of Electrochemistry

Aqueous sodium-ion batteries show promising application in fields of large-scale storage of intermittent renewable energies owing to the earth-abundant sodium resources and incombustible aqueous electrolytes. Primary factors determining whether they can be commercially utilized are low cost and long lifetime. Among current electrode materials, NASICON-type NaTi₂(PO₄)₃ arouses wide interests as an anode material for aqueous sodium-ion batteries as it offers a high specific capacity, fast Na-transport ability and reasonable working potential, however, suffering from insufficient cycling performance caused by severe dissolution of active materials in traditional aqueous electrolytes. In this work, a functional sulfate electrolyte …

Nitrogen-Sulfur Co-Doped Porous Carbon Preparation And Its Application In Lithium-Sulfur Batteries, Gui-Xiang Zhao, Wail Hafiz Zaki Ahmed, Fu-Liang Zhu

Journal of Electrochemistry

In recent years, lithium-sulfur (Li-S) batteries have been considered as a promising candidate for the next generation of energy storage system due to their ultrahigh theoretical capacity (1675 mAh·g^-1) and energy density (2600 Wh·kg^-1). However, the practical application of Li-S batteries is seriously limited by their insulating nature of sulfur, the shuttle effect of polysulfides (LiPSs), and volume expansion during charging and discharging. To overcome those disadvantages, one of the commonly methods is to infiltrate sulfur into porous conductive carbon framework, such as porous carbon, hollow carbon spheres, graphene, carbon nanotubes and some composites of the …

Structure Analysis Of Pemfc Cathode Catalyst Layer, Rui-Qing Wang, Sheng Sui

Journal of Electrochemistry

The sluggish oxygen reduction reaction (ORR) on the cathode of the proton exchange membrane fuel cell (PEMFC) has always been one of the key factors limiting its commercialization. The optimization of the cathode catalytic layer structure plays an important role in improving fuel cell performance and reducing production costs. In this paper, two different catalysts (platinum nanoparticles (Pt-NPs) and platinum nanowires (Pt-NWs)) were prepared by using catalyst coated substrate (CCS) method. By constructing a double-layer catalytic layer structure, we analyzed the effect of different catalytic layer structures by performing a single cell test. The results showed that the dense platinum …