Engineering Science and Materials Commons^™

Research Status And Application Prospects Of Limnpo4 As A New Generation Cathode Material For Lithium-Ion Batteries, Lai-Fen Qin, Yong-Gao Xia, Li-Peng Chen, Hua-Sheng Hu, Feng Xiao, Zhao-Ping Liu

Journal of Electrochemistry

Olivine-structured lithium manganese phosphate (LiMnPO₄) has the following advantages: excellent thermal stability, low cost, high safety and environmental benignity. Importantly, the theoretical energy density of LiMnPO₄ is about 20% higher than that of commercialized LiFePO₄ due to its higher Li⁺ intercalation potential of 4.1 V (vs. Li⁺/Li). Moreover, the high operating voltage of LiMnPO₄ is compatible with present non-aqueous organic electrolytes of lithium-ion batteries. Therefore, LiMnPO₄ is considered as a next generation cathode material for lithium-ion batteries. However, LiMnPO₄ suffers from poor electronic conductivity and low lithium diffusivity, resulting in …

Preparations And Applications Of Layered Carbon And Layered Carbon-Pbso4 Composite, Shu-Kai Zhang, Hao Zhang, Wei-Hua Xue, Jie Cheng, Wen-Feng Zhang, Gao-Ping Cao, Hai-Lei Zhao, Yu-Sheng Yang

Journal of Electrochemistry

The layered carbon materials (similar to graphene) have been synthesized by chemical vapor deposition (CVD) on the cheap catalyst (potassium or sodium carbonate substrate). The layered-carbon- lead sulfate (PbSO₄) composite could be prepared by in situ chemical deposition based on the layered carbon. The XRD, SEM and TEM results showed that the layered carbon materials was amorphous carbon layer, and the composite was a compound made of fine lead sulfate grains and layered carbon. Thermogravimetric analysis determined the carbon content in the composite. Adding a certain amount of layered carbon or layered-carbon-PbSO₄ composite into negative active materials …

Electrochemical Mass Spectrometric Study Of Lithium-Oxygen Batteries, Xin-Xiu Yan, Li-Po Ma, Zhang-Quan Peng

Journal of Electrochemistry

Mass Spectrometry, coupled with electrochemistry, is a powerful research tool to study mechanisms for a broad range of electrode reactions by identifying and quantifying reaction products and intermediates. In this review, we summarize the recent advances in the Li-O₂ battery researches offered by electrochemical mass spectrometry based on our group investigations. These include the research progresses in electrolytes, cathode materials (electrocatalysts), and parasitic reactions, i.e., the key issues associated with Li-O₂ research. In addition, we also discuss the effects of irreversible side reactions involved in battery systems on charge and discharge processes.

Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance, Meng-Yan Hou, Ke Wang, Xiao-Li Dong, Yong-Yao Xia

Journal of Electrochemistry

In present work, lithium-rich layered transition metal oxide (LLO) was synthesized by a co-precipitation method in combination with a solid-state reaction. The graphene wrapped Li-rich layered oxide composite (LLO/Gra) was obtained by sintering the LLO/GO composite at 300 ^oC for 30 min in an air. The morphologies and the electrochemical performances were characterized by means of SEM, TEM, XRD, XPS, EIS and charge/discharge tests. The results indicated that the LLOe particles were uniformly wrapped with graphene. The resulting material exhibited better rate capability than that of pristine LLO since the wrapped graphene demonstrated the enhanced electronic conductivity. Accordingly, the …

Research Progress In Carbon Coating On Lifepo4 Cathode Materials For Lithium Ion Batteries, Ning Zhang, Yong-Chang Liu, Cheng-Cheng Chen, Zhi-Qiang Zhu, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

Olivine-structured LiFePO₄ has been received much attention because of its flat voltage profile, low cost, abundant material supply and better environmental compatibility. However, the poor electronic and ionic conductivities have limited its application in industry. One of the best methods to improve the electrochemical performance is carbon coating. In this review, we summarize the recent developments of LiFePO₄/C cathode. Moreover, the different effects caused by coating methods and carbon sources, as well as the mechanism of carbon coating on the properties of LiFePO₄/C are reviewed.

Enhancing Stability Of Pem Fuel Cell Catalysts Via Support Changing, Xiao-Hong Xie, Zi-Dong Wei

Journal of Electrochemistry

The Pt/C catalyst with highly dispersed Pt nanoparticles supported on carbon has been widely used as the state-of the-art catalyst in proton exchange membrane fuel cells (PEMFCs), while the durability of Pt/C is one of the major barriers for large-scale applications of PEMFCs. Thus, enhancing the stability of Pt/C has been a hot issue in this field. In this review, we summarize the recent progress in enhancing the catalyst stability in the view of support material. The future prospects of the PEMFCs catalyst should focus on adopting more stable supports or strengthening the interactions between Pt and supports.

Pt/C Modified Proton Exchange Membrane For Improved Fuel Cell Performance, Zhi Cui, Chao Wang, Shui-Yun Shen, Feng-Jing Jiang, Jun-Liang Zhang

Journal of Electrochemistry

The property of proton exchange membrane greatly affects the performance of proton exchange membrane fuel cells (PEMFC). During the operation of a PEMFC, the water produced at the cathode, the water vapor from the humidified feed gas and the water migrated by electro-dragging will reach a balance in the membrane and determine the resistance of PEMFC, and thus affect the performance of PEMFC. Normally, the PEMFC performance strongly depends on the relative humidity of the feed gas, and the performance decreases at lower humidity as a result of lower proton conductivity of the membrane. In this paper, we proposed to …

Lithium Air Batteries: Non-Aqueous And Hybrid Systems, Sheng-Fu Tong, Ping He, Xue-Ping Zhang, Shi-Yong Zhao, Hao-Shen Zhou

Journal of Electrochemistry

Developing energy storage devices and new materials, which match the requirements in electric vehicles (EVs) and hybrid electric vehicles (HEVs), is an effective way to balance the contradiction between the social development and the shortage of fossil energy and environment pollution. Rechargeable lithium-air (Li-air) batteries consisting of Li and oxygen as the anodic and cathodic reactants, respectively, have attracted much attention during the past decade due to their high theoretical specific energy. According to work conditions, the most studied types of Li-air batteries are non-aqueous, hybrid, and solid state electrolyte Li-air batteries. Challenges still exist in cathodes, anodes, electrolytes and …

Electrolytes For Lithium And Lithium-Ion Batteries, Zong-Rang Zhang

Journal of Electrochemistry

This is an up-to-date book published by Springer last year and focuses on the field of the electrolytes for lithium and lithium-ion batteries. A brief introduction and review of this book are given in this paper. The main contents of this book are introduced briefly in the order of ten different chapters along with a short review of recent progress in those fields.

Preparation Of Zro2-Doped Nb/Pbo2 Electrode And Electrocatalytic Performance Of Methyl Orange Degradation, Li Zhang, Wen-Yan Dong, Tai-Lai Yang, Zhen-Hai Liang

Journal of Electrochemistry

The zirconium oxide (ZrO₂)-doped niobium based lead oxide (Nb/PbO₂) electrode was prepared by electrodeposition. The microstructures and electrochemical properties of Nb/ZrO₂+PbO₂ electrode were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), linear sweep voltammetry, electrochemical impedance spectroscopy and cyclic voltammotry. In addition, the Nb/PbO₂ electrode was used as an anode for the electrochemical degradation of methyl orange (MO). Results revealed that the ZrO₂ doping made the Nb/PbO2 electrode surface denser and rougher with smaller sized crystal particles, which increased the specific surface area and enhanced the electrocatalytic activity of the …

Yig: Bi2o3 Nanocomposite Thin Films For Magnetooptic And Microwave Applications, M Nur-E-Alam, Mikhail Vasiliev, Kamal Alameh, Viacheslav Kotov, Victor Demidov, Dmitry Balabanov

Research outputs 2014 to 2021

Y₃Fe₅O₁₂-Bi₂O₃ composite thin films are deposited onto Gd₃Ga₅O₁₂ (GGG) substrates and their annealing crystallization regimes are optimized (in terms of both process temperatures and durations) to obtain high-quality thin film layers possessing magnetic properties attractive for a range of technological applications. The amount of bismuth oxide content introduced into these nanocomposite-type films is controlled by adjusting the RF power densities applied to both Y₃Fe₅O₁₂ and Bi₂O₃ sputtering targets during the cosputtering deposition processes. The measured material properties of …

Effect Of Time Delay Between Etching And Adhesive Bonding (“Outlife” Time) On Lap-Shear Strength Of Aluminum Alloys Using Environmentally-Friendly P2 Etch, Josh Barkhimer, Matthew Erich, Gokul Nair

Materials Engineering

Raytheon Company currently uses a Forest Products Laboratory (FPL) paste etchant for preparing aluminum surfaces for adhesive bonding, and FPL is a source of hazardous hexavalent chromium. The goal of this study was to evaluate a less-toxic P2 paste etchant as a possible replacement. Coupons of 2024-T3, 6061-T6, and 7075-T6 grades of aluminum alloy were solvent-degreased, abrasively cleaned, and etched at room temperature using P2 paste following a strict protocol adopted from Raytheon. Coupons were then left exposed to air for assigned time intervals (or “outlife” times) of 0, 1, 4, 8, 16, and 63 or 72 hours. The aluminum …

Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley

Materials Engineering

Atom level computer simulations of the arabinan and cellulose interface were performed to better understand the mechanisms that give arabinan-cellulose composites (ArCCs) their strength with the goal to improve man-made ArCCs. The molecular dynamics (MD) software LAMMPS was used in conjunction with the ReaxFF/c force field to model the bond between cellulose and arabinan. A cellulose nanocrystal with dimensions 51 x 32 x 8 Å was minimized with various weight percent of water, 0%, 3%, 5%, 8%, 10%, and 12%. After the system was equilibrated for at least 100,000 femtoseconds, an arabinan molecule composed of 8 arabinose rings was added …

Non-Wetting Surface-Driven High-Aspect-Ratio Crystalline Grain Growth For Efficient Hybrid Perovskite Solar Cells, Cheng Bi, Qi Wang, Yongbo Yuan, Zhengguo Xiao, Jinsong Huang

Department of Mechanical and Materials Engineering: Faculty Publications

Large-aspect-ratio grains are needed in polycrystalline thin-film solar cells for reduced charge recombination at grain boundaries; however, the grain size in organolead trihalide perovskite (OTP) films is generally limited by the film thickness. Here we report the growth of OTP grains with high average aspect ratio of 2.3–7.9 on a wide range of non-wetting hole transport layers (HTLs), which increase nucleus spacing by suppressing heterogeneous nucleation and facilitate grain boundary migration in grain growth by imposing less drag force. The reduced grain boundary area and improved crystallinity dramatically reduce the charge recombination in OTP thin films to the level in …

Improving Product Design By Predicting Flexural Strength Of A Honeycomb Core Sandwich Panel Composite Using Ply Tensile Strength, Justin Lui, Javal Patel

Materials Engineering

The use of composite sandwich panels has increased in the aerospace industry. Prediction of a theoretical composite construction's flexural properties is important for efficient composite product designs. Utilizing the four point flexure geometry defined by Zodiac Aerospace, Santa Maria, CA, a mechanical model was derived to predict the flexural behavior of a theoretical honeycomb core sandwich composite using laminate tensile properties. The most common failure mode of Zodiac Aerospace’s four point bend test is a failure in tension of the bottom laminate. Given this information, ASTM D3039 (Standard Test Method for Tensile Properties of Polymer Matrix Composite Materials) was chosen …

Analysis Of A Carbon Fiber Reinforced Polymer Impact Attenuator For A Formula Sae Vehicle Using Finite Element Analysis, John T. Rappolt

Master's Theses

The Hashin failure criteria and damage evolution model for laminated fiber reinforced polymers are explored. A series of tensile coupon finite element analyses are run to characterize the variables in the physical model as well as modeling techniques for using an explicit dynamic solver for a quasi-static problem. An attempt to validate the model on an axial tube crush is presented. It was found that fiber buckling was not occurring at the impactor-tube interface. Results and speculation as to why the failure initiation is incorrect are discussed. Lessons learned from the tube crush are applied successfully to the quasi-static Formula …

Simulation Of Drainage Rates Of A Flexible Fiber Network On Wire Screen, Yihsin Tang

Masters Theses

A forming process of a fiber mat over a filter or wire net/screen, which can move horizontally, is numerically simulated. A lattice Boltzmann equation is used to simulate fluid velocity, vorticity and structures and a lattice spring model is employed to mimic the collective motion of up to 750 flexible fibers, with aspect ratio of 20.

The interaction between the fluid and fibers is handled by an immersed boundary method. The fiber motion is driven by the hydrodynamic forces and the gravity of both fluid and solid fibers and disturbed by the horizontal shear force between the fluid and the …

Me-Em Enewsbrief, June 2015, Department Of Mechanical Engineering-Engineering Mechanics, Michigan Technological University

Department of Mechanical and Aerospace Engineering eNewsBrief

No abstract provided.

Predictive Modeling Of Oxygen Transmission Through Micro-Perforations For Packaging Applications, Ayman Abdellatief, Bruce A. Welt, Jason Butler, Eric Mclamore, Arthur Teixeira, Sanjay Shukla

Journal of Applied Packaging Research

Methods for creating precise perforations in respiring produce packaging are being increasingly adopted. Knowledge of oxygen transfer through perforated packaging and oxygen distribution in packages is necessary for successful packaging design of fresh produce. An approach to modeling perforated packaging performance was developed using a cylindrical chamber with precision perforations using Fick’s second law. The model was simulated using two techniques including Finite Element Method (FEM) using commercially available software and Finite Volume Method (FVM) through programming. Perforations were approximated as a source term in the second method. Both simulation techniques showed trends similar to experimental data.

Characterizing Water As Gap Fill For Double Glazing Units, Bright Adu

Masters Theses & Specialist Projects

The use of sunlight has always been a major goal in the design and operation of commercial buildings to minimize electrical consumption of artificial lighting systems. Glazing systems designed to allow optimal visible light transmission also allow significant unwanted direct solar heat gain caused by infrared light. Conversely, glazing systems that are designed to reflect unwanted direct solar heat gain significantly reduce the transmittance of visible light through windows. The goal of this research was to characterize the performance of water as gap-fill for double-glazing units in eliminating the compromises that exist in current glazing systems with respect to light …