Browse Topic: Electrolytes

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Test Method for the Determination of Total Acidity in Polyol Ester and Diester Gas Turbine Lubricants by Automatic Potentiometric TitrationARP5088C (Current)11/26/2025
The test method describes the procedure for determination of the total acid number of new and degraded polyol ester and diester based gas turbine lubricants by potentiometric titration technique. The method was validated to cover an acidity range 0.05 to 6.0 mg KOH g-1. The method may also be suitable for the determination of acidities outside of this range and for other classes of lubricant.
E-34 Propulsion Lubricants Committee
‘Laxatives’ may ease challenge of lithium-ion alternative20AUTP02_101/1/2020
The R&D dimension of the automotive industry often reveals novel solutions and cross-linking between materials, but a team of international scientists has come up with something truly unusual: boosting supercapacitor power and efficiency using newly developed “laxatives.” It's all about developing improved electrolytes as part of a program to enhance supercapacitor performance, making them more practical with enhanced energy storage for use in hybrid and electric vehicles (EVs). To do this, the team designed a new class of detergents involving the use of self-assembled nanostructures in detergent-like ionic liquids (IL), to facilitate improved charge storage at electrified interfaces. These detergents are chemically similar to human laxatives, said Dr. Gavin Hazell, a chemistry lecturer at the University of Chester's Faculty of Science and Engineering, and a member of the international team: “A discovery of this kind utilizes scientists from across the globe. We have a very diverse set of skills including synthetic chemistry, advanced structural, microscopy and computational methods.”
Birch, Stuart
Products of Tomorrow: September 2019TBMG-351239/1/2019
Hybrid Cathodes Could Boost Energy Capacity of Lithium BatteriesTBMG-349268/1/2019
Today's lithium-ion batteries use cathodes (one of the two electrodes in a battery) made of a transition metal oxide. Batteries with cathodes made of sulfur are considered a promising alternative to reduce weight. Designers of lithium-sulfur batteries face a tradeoff. The cathodes of such batteries are usually made in one of two ways: intercalation or conversion. Intercalation types — which use compounds such as lithium cobalt oxide — provide a high volumetric energy density, packing a lot of punch per volume because of their high densities. These cathodes can maintain their structure and dimensions while incorporating lithium atoms into their crystalline structure.
Mechanical Behavior of Representative Volume Element Specimens of Lithium-Ion Battery Modules without and with Electrolyte under Quasi-Static and Dynamic In-Plane Compressive Loading Conditions05-12-03-00147/2/2019
Abstract Small rectangular representative volume element (RVE) specimens of lithium-ion battery modules without and with electrolyte were tested under quasi-static and dynamic in-plane constrained compressive loading conditions. Effects of electrolyte and loading rate on the compressive behavior of RVE specimens were examined. The test results show that the average buckling stress of the specimens with electrolyte is higher than that of the specimens without electrolyte under both quasi-static and dynamic loading conditions. The test results also show that the average buckling stress of the specimens under dynamic loading conditions is higher than that of the specimens under quasi-static loading conditions, without or with the presence of electrolyte in the specimens. The percentage of increase of the average buckling stress of the specimens due to electrolyte under dynamic loading conditions is more than that of the specimens under quasi-static loading conditions. The percentage of increase of the average buckling stress for the specimens with electrolyte from the quasi-static to dynamic loading conditions is more than that for the specimens without electrolyte.
Kim, Eui Seop, Sung, Shin-Jang, Hong, Sung-Tae, Pan, Jwo
Battery Electrolyte Doubles Driving Range for Electric VehiclesTBMG-346106/1/2019
Conventional electrolytes used in lithium-ion batteries that power household electronics like computers and cellphones are not suitable for lithium-metal batteries. Lithium-metal batteries that replace a graphite electrode with a lithium electrode are the holy grail of energy storage systems because lithium has a greater storage capacity and, therefore, a lithium-metal battery has double or triple the storage capacity. That extra power enables electric vehicles to drive more than two times longer between charges.
Wood-Based Technology Creates Electricity from HeatTBMG-346086/1/2019
Researchers have transformed a piece of wood into a flexible membrane that generates energy from the same type of electric current (ions) on which the human body runs. This energy is generated using charged channel walls and other unique properties of the wood’s natural nanostructures. With this new wood-based technology, a small temperature differential can be used to efficiently generate ionic voltage.
Graphene Coating Takes Oxygen Out of Lithium Battery FiresTBMG-346016/1/2019
Lithium batteries allow electric vehicles to travel several hundred miles on one charge. Their capacity for energy storage is well known — so is their tendency to occasionally catch on fire. This “thermal runaway” occurs most frequently when the batteries overheat or cycle rapidly.
Fabric Alternative to Batteries for Wearable DevicesTBMG-341484/1/2019
Wearable biosensors for health monitoring lack a lightweight, long-lasting power supply. A new method was developed for making a charge-storing system that is easily integrated into clothing for embroidering a charge-storing pattern onto any garment.
Electric double layer capacitors prepared with polyvinyl alcohol and multi-walled carbon nanotubes2018-36-03139/3/2018
Portable electronics, wearables, electric vehicles and solar cells are sectors in increasingly development which include innovation and miniaturization of the devices. In this scenario, the development of smaller and lightweight energy storage devices, which store more energy, is required. Besides, it is desirable for these devices to be environmentally friendly to minimize pollution. In an attempt to meet these requirements, this work purposes the development and the characterization of nanofibers-based electrode composed of Polyvinyl alcohol (PVA) and multi-walled carbon nanotubes (MWCNT) for electric double layer capacitors (ELCDs) devices with aqueous electrolyte. This composite has been prepared by electrospinning technique and consolidate an electrical conductive and high-surface material electrode. After that, the PVA/MWCNT electrode was assembled in coin cell device with Sodium Sulfate (Na2SO4) electrolyte for electrochemical characterization. The characterization results showed that EDLCs devices present specific capacitance of ∼4.8 Fg-1, energy density of ∼0.1 Wh kg-1, power density of ∼600W kg-, fast charge transfer at electrode/electrolyte interface and high lifetime All these results encourage further development on PVA/MWCNT materials as electrode for EDLCs and Li-Air batteries devices. This new generation of devices are opening niches of applications on multi billionaire markets from communication to transport.
Real, Carla Giselle Martins, Vicentini, Rafael, Nunes, Willian Gonçalves, Boas, Otávio Vilas, Costa, Lenon Henrique, Soares, Davi Marcelo, Zanin, Hudson
Self-Powered Paper Patch Measures GlucoseTBMG-324908/1/2018
The most common methods for glucose self-testing involve monitoring glucose levels in blood. These conventional measurements are not suitable for preventing hypoglycemia during exercise. The underlying process relies on invasive and inconvenient blood sampling, which can cause skin irritation with perspiration containing electrolytes and proteins. In addition, blood testing requires that diabetics keep testing equipment such as lancets, alcohol, and a glucometer with them during exercise.
Aluminum Electroplating Using Bromide SaltsTBMG-283142/1/2018
Corrosion of structural materials is a serious problem for industrial and civil infrastructure worldwide, costing billions of dollars, and hampering gross domestic product. Corrosion also presents a threat to the environment and public safety, with highways and bridges losing structural integrity, and hazardous materials leaching into soils, waterways, and aquifers.
Nanoporous Material Reduces Computer Energy ConsumptionTBMG-281641/1/2018
In order to store information in the conventional magnetic memories of electronic devices, the material’s small magnetic domains are oriented “up” or “down” by using externally applied magnetic fields. To generate these fields, it is necessary to produce electric currents; however, these currents heat up materials, and a large amount of energy is needed to cool them.
Process Turns Carbon Dioxide into 3D Graphene with Microporous SurfaceTBMG-281561/1/2018
The conversion of carbon dioxide to useful materials usually requires high energy input due to its ultrahigh stability. A heat-releasing reaction between carbon dioxide and sodium was developed to take carbon dioxide and turn it into 3D graphene with micropores across its surface.
Sulfuric Acid Anodizing of Aluminum and Aluminum AlloysAMS03_25A (Current)10/4/2017
This SAE Standard specifies the properties of sulphuric acid anodizing of aluminum and aluminum alloys.
AMS B Finishes Processes and Fluids Committee
Magnesium Alloys, Anodic Treatment ofAMSM45202B (Current)9/20/2017
This specification covers the requirements for equipment, materials and procedures to be used in anodic treatments for magnesium base alloys for the purpose of increasing their corrosion resistance or producing surfaces suitable for the application of a protective organic finish.
AMS B Finishes Processes and Fluids Committee
Faster, Better, Economic - Newest Acid Zinc-Nickel Technology for Brake Caliper Plating2017-01-25079/17/2017
The demand for zinc-nickel coatings continuously increases in the automotive industry due to their high corrosion protection as well as superior wear and heat resistance compared to pure zinc platings. The state-of-the-art plating systems in the brake caliper industry are acid zinc-nickel electrolytes, as only they allow for direct plating on cast iron. Cast iron is the most common base material for the production of automotive brake components due to excellent mechanical and thermal properties. Well suited coatings will preserve the functional properties and provide additional advantages like improved corrosion protection and homogeneous and long lasting appearance. Consistently increasing quality demands, extended warranty periods and cost pressure lead to further developments and force the industry to look for new solutions. Therefore improvement of throwing power (thickness distribution) of acid zinc-nickel electrolytes would allow for a reduction in plating time and thus an increase in productivity. More homogeneous coatings on the other hand will lead to an improvement of corrosion resistance and quality. With an appropriate post-treatment consisting of passivate and reactive inorganic sealer, a high-end system with superior cathodic corrosion protection, highest wear resistance and perfect appearance is achieved. This study will introduce Atotech´s new ammonium and boric acid-free acid zinc-nickel electrolyte - Zinni® 220 - which, as a result of the significantly improved throwing power, sets new standards in acid zinc-nickel plating. It opens enormous possibilities to improve quality and productivity while keeping the highest corrosion protection and perfect appearance. The superior thickness distribution and nickel incorporation will be presented and compared to conventional acid zinc-nickel electrolytes. Overall this results in higher plating quality at reduced cost and improved productivity.
Hoch, Matthias, Kaczmarek, Michal, Ahr, Markus
Safer, Cleaner, Corrosion-Protecting Metal CoatingsTBMG-272007/1/2017
LumiShield Pittsburgh, PA For more info click
The Pre-Treatment and Protection of Steel Items of Specified Maximum Tensile Strength Exceeding 1450 MPaAMS03_4A (Current)3/21/2017
This SAE Standard specifies the special treatments and precautions that are to be observed when protective and other surface treatments are applied to items, including springs, made from steel of specified maximum tensile strength exceeding 1450 MPa. The requirements of this Standard qualify those in process specifications and override the latter where there is conflict. The Standard also gives advice on design, manufacture, and preparation of items prior to cleaning and protection.
AMS B Finishes Processes and Fluids Committee
Advanced Finishes for Brake Components and Other Castings2016-01-19519/18/2016
Caused by a number of beneficial properties inherently from the zinc-nickel material, this electrodeposited alloy is used more and more for cathodically protecting layers on ferrous components like cast iron brake calipers. Direct plating from acidic solutions is the state-of-the-art solution for zinc-nickel surface finishing of these components. To contribute to the continuous improvement of the final component and reduce the finishing cost, areas for improvement have been scrutinized in a current finishing system. Areas for improvement have been identified in the uniformity of the nickel distribution within different current densities and in the handling and economy of the metallic zinc anodes used for zinc metal replenishment. While today’s acidic zinc-nickel electrolytes suit and usually exceed the requirements for an alloy containing 10-15% nickel, nickel incorporation may drop just below 12% incorporation rate in areas which are plated at high current densities. Formation of white corrosion products is observed in those areas earlier than in areas bearing higher (>12%) nickel. Development on the zinc-nickel plating electrolyte’s additive system has resulted in a significantly more uniform plated deposit with improved resistance against white corrosion. Previous disadvantages in the plating system including rising metal concentrations, anode passivation and insufficient zinc metal utilization will be overcome using the new membrane anode system. This separates the zinc metal anode from the plating bath. The electrolyte can then be operated at constant metal concentrations, constant anode voltages, with no need to remove anodes in idle periods, without any anode reactivation and significantly better anode metal utilization. These developments provide important contributions for improved operating efficiencies through higher productivity and improved material economy. The significant effect of these developments on higher and more consistent quality of the plated layers finally also contributes to the overall reliability of cast iron brake systems.
Dingwerth, Björn
Lithium Fluoride as a Polysulfide Shuttle Inhibitor for Lithium Sulfur ChemistryTBMG-221996/1/2015
Lyndon B. Johnson Space Center, Houston, Texas
Sulfuric Acid Anodizing of Aluminum and Aluminum AlloysAMS03_25 (Historical)5/21/2015
This SAE Standard specifies the properties of sulphuric acid anodizing of aluminum and aluminum alloys.
AMS B Finishes Processes and Fluids Committee
Methods for Determining Plastic Deformation in Sheet Metal StampingsJ863_201504 (Current)4/28/2015
This SAE Recommended Practice describes methods for determining plastic deformation encountered in the forming or drawing of sheet steel.
Metals Technical Committee
The Pre-Treatment and Protection of Steel Items of Specified Maximum Tensile Strength Exceeding 1450 MPaAMS03_4 (Historical)4/27/2015
This SAE Standard specifies the special treatments and precautions that are to be observed when protective and other surface treatments are applied to items, including springs, made from steel of specified maximum tensile strength exceeding 1450 MPa. The requirements of this Standard qualify those in process specifications and override the latter where there is conflict. The Standard also gives advice on design, manufacture, and preparation of items prior to cleaning and protection.
AMS B Finishes Processes and Fluids Committee
Zinc Coated Press-Hardening Steel - Challenges and Solutions2015-01-05654/14/2015
Press-hardening steels get more and more popular for body in white applications as an approach to meet the demands of passenger safety and CO2 reduction. Unlike the larger part of the structure that is typically zinc coated, the majority of the PHS parts is either uncoated or aluminum silicon coated. This paper shall give an overview of press-hardening steels with zinc coatings with detailed results for corrosion resistance, weldability and mechanical properties for strength levels of 490 to 1800 MPa. Furthermore as for zinc coated material maintaining a robust press-hardening process is of even higher importance than for uncoated or AlSi coated material. A range of different processes including indirect and direct process are shown in detail. Especially the topic of micro-cracks, mechanisms and avoidance of micro-cracks in the direct process will be discussed. Results from industrial and semi industrial production are shown.
Kurz, Thomas, Luckeneder, Gerald, Manzenreiter, Thomas, Schwinghammer, Harald, Sommer, Andreas
Electrochemically Powered Vehicles: Current Possibilities and Investigation of the Li-O2 Electrochemical Reaction on Catalyst Surfaces: Implications for a Metal-Air Battery2015-01-11794/14/2015
Significant research has been underway for many years to develop technologies to electrochemically power vehicles with limited success. Unfortunately, most technologies fail to achieve theoretical performance and/or are prohibitively too expensive for mass marketed vehicles. Most of the issues with electrochemical technologies can ultimately be attributed to materials issues, whether it is cost, durability, or activity. A broad examination of potential electrochemical technologies is provided identifying key materials issues with each. Included are the results of recent research involving lithium-oxygen batteries. The observations from this research have identified the electrochemical product, lithium peroxide, and its properties to be the most pressing material issue for lithium-oxygen battery. A future research vision is proposed counter to the current research trend of electrocatalyst/electrolyte development. The focus will be to understand the formation of lithium peroxide and subsequent control of its electrical properties by attempting to control the structure and morphology of the desired product and reduce parasitic reactions.
Brooks, Christopher J., Kreidler, Eric
Degradation Analysis of Pouch Cell Using High-Energy Cathode Material for Advanced Lithium-ion Battery2015-01-11934/14/2015
Lithium-rich layered oxide, expressed as xLi2MnO3-(1-x) LiMO2 (M = Ni, Co, Mn, etc.), exhibits a high discharge capacity of 200 mAh/g or more and a high discharge voltage at a charge of 4.5 V or more. Some existing reports on cathode materials state that lithium-rich layered oxide is currently the most promising candidate as an active material for high-energy-density lithium-ion cells, but there are few reports on the degradation mechanism. Therefore, this study created a prototype cell using a lithium-rich layered cathode and a graphite anode, and analyzed the degradation mechanism due to charge and discharge. In order to investigate the causes of degradation, changes in the bulk structure and surface structure of the active material were analyzed using high-resolution X-ray diffraction (HRXRD), a transmission electron microscope (TEM), X-ray absorption fine structure (XAFS), and scanning electron microscope/energy dispersive X-ray spectroscopy (SEM-EDX). The results showed that dissolution of transition metals from the cathode active material is the main factor producing degradation of the full cell capacity, and that this is promoted by excessive reductive decomposition of the electrolyte due to deposition of the transition metals on the anode. In addition, voltage fade originates in the cathode active material, and is promoted by changes in the local structure resulting from oxygen release from the crystals due to charge and discharge.
Maeyama, Hiroto, Sukigara, Toru
Wearable Electrolyte Sensor Provides Instant ReadingsTBMG-200777/1/2014
Electrolytes, such as potassium, calcium, magnesium, and other salts are essential in carrying nerve impulses that tell the heart and other muscles when to contract or relax. A proper balance of them in the human body is required for the normal function of cells and organs. Realizing that laboratory analyses can be expensive, and that patients, athletes, and soldiers would prefer a pain-free, wrist-worn diagnostic device that can analyze, continuously record, and even remedy low electrolyte levels, researchers at Sandia National Laboratories, Albuquerque, NM, have developed and are patenting a prototype model that can analyze various electrolyte levels on the spot, yet fit in a palm or be worn on a wrist. The device, when commercially available, could decrease the time users would spend in emergency rooms, lab testing facilities, or doctors’ offices.
Improved Cyclic Performances of Li-Sulfur Batteries with Sulfone-Based Electrolyte2014-01-18444/1/2014
The effects of electrolyte on the cyclability of Li/S battery were investigated in this work. The electrochemical properties of single component ether solvents and a binary mixture of ether solvents were studied. These ether-based electrolytes have polysulfide shuttle problems which result in severe low Coulombic efficiency. To overcome these issues, sulfone-based solvent which forms a stable passivation film at the anode surface were used. As a result, the proper composition of sulfone-based electrolyte were obtained. Its capacity and reversible capacity retention were improved to 715 mAh/g and 72.6% which were increased by 52.1% and 63.1%, respectively, compared to those of ether-based electrolyte.
Shin, Nary, Ryu, Kyoung Han, Kim, Yong-Gu, Lee, Ho-Taek
Li-Ion Electrolytes Containing Flame-Retardant AdditivesTBMG-234212/1/2014
In order to improve the safety and performance of lithium- ion cells, especially over a wide operating temperature range, a number of Li-ion electrolytes have been developed that contain flame-retardant additives in conjunction with fluorinated co-solvents to provide a safe, wide-operating-temperature- range system. Previously, fluorinated esters were incorporated into multi-component electrolyte formulations and their performances have been demonstrated over a wide temperature range (–60 to +60 °C). The fluorinated esters co-solvents were employed due to their favorable properties and improved safety characteristics, mainly associated with their low flammability associated with their halogenated nature.
Aluminum Anodizing Technology for Reusable Medical EquipmentTBMG-1875712/1/2013
Aluminum outperforms other materials to become an ideal choice for manufacturing of medical instruments, equipment, and devices mainly due to its intrinsic sustainable qualities. It is recyclable, lightweight, strong, non-toxic, inexpensive, easily machined and accepts many types of finishes. Metal integrity is crucial for medical devices that must hold tight tolerances and handle harsh conditions of cleaning and sterilization to perform their desired tasks. Medical coatings such as anodizing are used in many applications in the medical industry, including medical cases, trays, instruments, and general hospital accessories and devices made out of aluminum.
Multi-Physics Numerical Analysis of PEMFC for Automobile Application2013-01-04764/8/2013
Polymer Electrolyte Membrane Fuel Cell (PEMFC) is regarded as a potential alternative clean energy source for automobile applications. Key challenges to the acceptance of PEMFC for automobiles are the cost reduction, improvement in power density for its compactness, and cold-start capability. High current density operation is a promising solution for them. However, high current density operation under normal and sub-zero temperature requires more oxygen flux for the electrochemical reaction in the catalyst layer, and it causes more heat and water flux, resulting in the significant voltage losses. So, the theoretical investigation is very helpful for the fundamental understanding of complex transport phenomena in high current density operation under normal and sub-zero temperature. In this study, the numerical model was established to elucidate the impacts of mass transport phenomena on the cell performance through the numerical validation with experimental and visualization results. The results indicated that the higher current density operation causes non-uniform reaction distribution, resulting in lower cell performance under normal temperature and less accumulated produced water under sub-zero temperature. They also quantitatively indicated the limiting factors for this non-uniform reaction distribution such as heat and water transport in rib/channel direction, oxygen transport resistance near Pt area, and the water transport through the membrane.
Tabuchi, Yuichiro, Kotaka, Toshikazu, Wang, Chao-Yang
Electrochemical Energy Storage MaterialsTBMG-156872/1/2013
One of the most important requirements in next-generation batteries is to concurrently deliver high energy density and high power density (fast charge-discharge rates). The high power density requirement can be met with enhanced ion and electron transport kinetics in batteries, which in turn requires active materials with high ion diffusion constants and conductive additives or architectures for faster electron transport to respective current collectors. It is well known that nanostructuring the electrode materials would significantly enhance the characteristic time constant for ion diffusion, thereby reducing the intercalation/deintercalation time.
High Performance Corrosion Protection for Brake Components: Direct Zinc-Nickel Application and Post-Treatment2012-01-18319/17/2012
Cast-iron is a well suited material for manufacturing automotive brake components due to excellent mechanical and thermic properties. The application of a well chosen cathodically protecting coating adds durable appearance and preservation of the functional properties of the components. The selection of the right coating is driven by multiple factors of which economic considerations will always rank within the highest priorities next to protection performance and the appearance of the coating. Aiming for the highest possible performance in cathodic corrosion protection coatings leads directly to zinc-nickel coatings. Zinc-nickel coatings are already state-of-the-art in the finishing of mild steel and carburized steel materials in the automotive industry, mostly being plated from alkaline plating solutions. The application of alkaline solutions to cast iron material is not feasible under industrial conditions at an acceptable reject rate due the electrochemical properties of the cast iron in these electrolytes. Therefore, as a workaround a two layer system with a first zinc layer from acidic electrolytes to cover the cast iron followed by zinc-nickel from an alkaline electrolyte was the often chosen alternative for this application. Those two layer systems are more expensive and bear multiple risks which hamper the reproducibility of the achieved corrosion protection performance. Alternatively, ammonium containing acidic electrolytes are applied directly to the cast iron material. Those electrolytes could not always be applied due to environmental and technical considerations. The newest generation of Atotech's acidic zinc-nickel electrolytes provides consistent deposition of zinc-nickel with homogenous nickel incorporation directly to the cast iron material while being free of ammonium and boric acid. With perfectly matched trivalent chromates and reactive inorganic sealers, a state-of-the-art high end system for cathodic corrosion protection and appearance is applied.
Dingwerth, Bjoern O.
Imidazolium-Based Polymeric Materials as Alkaline Anion-Exchange Fuel Cell MembranesTBMG-142328/1/2012
Polymer electrolyte membranes that conduct hydroxide ions have potential use in fuel cells. A variety of polystyrenebased quaternary ammonium hydroxides have been reported as anion exchange fuel cell membranes. However, the hydrolytic stability and conductivity of the commercially available membranes are not adequate to meet the requirements of fuel cell applications. When compared with commercially available membranes, polystyrene-imidazolium alkaline membrane electrolytes are more stable and more highly conducting. At the time of this reporting, this has been the first such usage for imidazolium-based polymeric materials for fuel cells.
Asymmetric Supercapacitor for Long-Duration Power StorageTBMG-140807/1/2012
A document discusses a project in which a series of novel hybrid positive electrode materials was developed and tested in asymmetric capacitors with carbon negative electrodes. The electrochemical performance of the hybrid capacitors was characterized by cyclic voltammetry and a DC charge/discharge test. The hybrid capacitor exhibited ideal capacitor behavior with an extended operating voltage of 1.6 V in aqueous electrolyte, and energy density higher than activated carbon-based supercapacitors.
Three-Dimensional Porous Particles Composed of Curved, Two-Dimensional, Nano-Sized Layers for Li-Ion BatteriesTBMG-138856/1/2012
Building on previous knowledge acquired through research on thin-film batteries, three-dimensional (3D) porous macroscopic particles consisting of curved two-dimensional (2D) nano-structures of Si may bring unique advantages for Si anode technology. Prior work on thin Si films showed that during Li insertion, large-area Si films mostly accommodate the volume changes via variation in thickness. Therefore, the changes in the external surface area can fundamentally be minimized and thus, formation of a stable, solid electrolyte interphase (SEI) should be easier to achieve. In contrast, Si nanoparticles expand uniformly in all dimensions and thus, their outer surface area (where SEI forms) changes dramatically during insertion/extraction of Si. The low elasticity of the SEI makes it difficult to achieve the long-term stability under cycling load. Further, thin Si films have lower surface area (for the same mass), in comparison to Si nanoparticles, and better potential for achieving low irreversible capacity losses on the first and subsequent cycles.
Electrochemical Ultracapacitors Using Graphitic NanostacksTBMG-135715/1/2012
Electrochemical ultracapacitors (ECs) have been developed using graphitic nanostacks as the electrode material. The advantages of this technology will be the reduction of device size due to superior power densities and relative powers compared to traditional activated carbon electrodes. External testing showed that these materials display reduced discharge response times compared to state-of-the-art materials. Such applications are advantageous for pulsed power applications such as burst communications (satellites, cell phones), electromechanical actuators, and battery load leveling in electric vehicles. These carbon nanostructures are highly conductive and offer an ordered mesopore network. These attributes will provide more complete electrolyte wetting, and faster release of stored charge compared to activated carbon.
Geometry-Resolved Electro-Chemistry Model of Li-Ion Batteries2012-01-06634/16/2012
The paper presents a simulation approach to Li-Ion batteries based on geometrically resolved electrodes. This means that solid particles and the space occupied by electrolyte are not overlapping but are represented by contiguous, arbitrarily shaped volumes. The solid-electrolyte interface is explicitly resolved and thus allows detailed modeling of electro-chemical processes that are essential for studying performance of the battery cell. Finite volume method is used to solve the equations governing the mass and thermal energy conservation in solid and electrolyte, as well as the distribution of electric potential. The solution domain is discretized in contiguous control volumes of arbitrary polyhedral shape, with conformal interface between solid and fluid regions. Butler-Volmer equation is used to describe the kinetics of solid-electrolyte interface. For the time being, representative geometries of electrodes are manufactured using CAD-tools, but real geometries obtained using scanning methods will be used in future. One example application is presented and the results are compared to those obtained using a widely accepted one-dimensional method.
Spotnitz, Robert, Kaludercic, Boris, Muzaferija, Samir, Peric, Milovan, Damblanc, Gaetan, Hartridge, Steve
Better Proton-Conducting Polymers for Fuel-Cell MembranesTBMG-126461/1/2012
Polyoxyphenylene triazole sulfonic acid has been proposed as a basis for development of improved proton-conducting polymeric materials for solidelectrolyte membranes in hydrogen/air fuel cells. Heretofore, the proton-conducting membrane materials of choice have been exemplified by a family of perfluorosulfonic acid-based polymers (Nafion7 or equivalent). These materials are suitable for operation in the temperature of 75 to 85 °C, but in order to reduce the sizes and/or increase the energy-conversion efficiencies of fuelcell systems, it would be desirable to increase temperatures to as high as 120 °C for transportation applications, and to as high as 180 °C for stationary applications. However, at 120 °C and at relative humidity values below 50 percent, the loss of water from perfluorosulfonic acid-based polymer membranes results in fuel-cell power densities too low to be of practical value. Therefore, membrane electrolyte materials that have usefully high proton conductivity in the temperature range of 180 °C at low relative humidity and that do not rely on water for proton conduction at 180 °C would be desirable.
Handheld Universal Diagnostic SensorTBMG-126111/1/2012
The rHEALTH technology is designed to shrink an entire hospital testing laboratory onto a handheld device. A physician or healthcare provider performs the test by collecting a fingerstick of blood from a patient. The tiny volume of blood is inserted into the rHEALTH device (see figure). Inside the device is a microfluidic chip that contains small channels about the width of a human hair. These channels help move the blood and analyze the blood sample. The rHEALTH sensor uses proprietary reagents called nanostrips, which are nanoscale test strips that enable the clinical assays. The readout is performed by laser-induced fluorescence. Overall, the time from blood collection through analysis is less than a minute.
New Energy Source Powers Single-Use Mil/Aero EquipmentTBMG-1226212/1/2011
Until recently, single-use high energy devices were typically powered by reserve/thermal batteries using decades-old technology. Recognizing that battery performance limitations could hinder new product development, the U.S. DoD identified a “critical need” for a new generation of high-power, long life batteries.
Magnesium Alloys, Anodic Treatment ofAMSM45202A (Historical)11/21/2011
This specification covers the requirements for equipment, materials and procedures to be used in anodic treatments for magnesium base alloys for the purpose of increasing their corrosion resistance or producing surfaces suitable for the application of a protective organic finish.
AMS B Finishes Processes and Fluids Committee
Li-Ion Cells Employing Electrolytes With Methyl Propionate and Ethyl Butyrate Co-SolventsTBMG-1136510/1/2011
Future NASA missions aimed at exploring Mars and the outer planets require rechargeable batteries that can operate at low temperatures to satisfy the requirements of such applications as landers, rovers, and penetrators. A number of terrestrial applications, such as hybrid electric vehicles (HEVs) and electric vehicles (EVs) also require energy storage devices that can operate over a wide temperature range (i.e., –40 to +70 °C), while still providing high power capability and long life. Currently, the state-of-the-art lithiumion system has been demonstrated to operate over a wide range of temperatures (–30 to +40 °C); however, the rate capability at the lower temperatures is very poor. These limitations at very low temperatures are due to poor electrolyte conductivity, poor lithium intercalation kinetics over the electrode surface layers, and poor ionic diffusion in the electrode bulk.
Use of Additives to Improve Performance of Methyl Butyrate-Based Lithium-Ion ElectrolytesTBMG-1136410/1/2011
This work addresses the need for robust rechargeable batteries that can operate well over a wide temperature range. To this end, a number of electrolyte formulations have been developed that incorporate the use of electrolyte additives to improve the high-temperature resilience, low-temperature power capability, and life characteristics of methyl butyrate-based electrolyte solutions. These electrolyte additives include mono-fluoroethylene carbonate (FEC), lithium oxalate, vinylene carbonate (VC), and lithium bis(oxalato)borate (LiBOB), which have been shown to result in improved high-temperature resilience of all carbonate-based electrolytes.
Self-Activating and Doped Tantalate PhosphorsTBMG-107128/17/2011
Phosphors are useful in numerous applications including imaging, detection, and lighting. They come in forms of thin films, monoliths, or powders for miscellaneous devices, or dispersible nanoparticles for applications such as biomedical imaging. Oxide phosphors, as apposed to chalcogenides or pnictides, have inherent chemical and thermal stability and minimal toxicity to the biosphere. Tantalates are very promising materials for these applications because they are especially robust and resistant to chemical degradation. Studies have shown that rare-earth tantalates are excellent host lattices for europium (Eu)-doped red-emitting phosphors, excited by blue light.
Li Anode Technology for Improved PerformanceTBMG-107418/1/2011
A novel, low-cost approach to stabilization of Li metal anodes for high-performance rechargeable batteries was developed. Electrolyte additives are selected and used in Li cell electrolyte systems, promoting formation of a protective coating on Li metal anodes for improved cycle and safety performance.
Self-Activating and Doped Tantalate PhosphorsTBMG-143048/1/2011
Phosphors are useful in numerous applications including imaging, detection, and lighting. They come in forms of thin films, monoliths, or powders for miscellaneous devices, or dispersible nano particles for applications such as biomedical imaging. Oxide phosphors, as apposed to chalcogenides or pnictides, have inherent chemical and thermal stability and minimal toxicity to the biosphere. Tantalates are very promising materials for these applications because they are especially robust and resistant to chemical degradation. Studies have shown that rare-earth tantalates are excellent host lattices for europium (Eu)-doped red-emitting phosphors, excited by blue light.
Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental MonitoringTBMG-104877/6/2011
An ambient temperature oxygen microsensor, based on a Nafion polymer electrolyte, has been developed and was microfabricated using thin-film technologies. A challenge in the operation of Nafion-based sensor systems is that the conductivity of Nafion film depends on the humidity in the film. Nafion film loses conductivity when the moisture content in the film is too low, which can affect sensor operation. The advancement here is the identification of a method to retain the operation of the Nafion films in lower humidity environments. Certain salts can hold water molecules in the Nafion film structure at room temperature. By mixing salts with the Nafion solution, water molecules can be homogeneously distributed in the Nafion film increasing the film’s hydration to prevent Nafion film from being dried out in low-humidity environment. The presence of organics provides extra sites in the Nafion film to promote proton (H+) mobility and thus improving Nafion film conductivity and sensor performance.
Advanced Carbons for Electrochemical CapacitorsTP-AAB-AABC_EUROPE_2011_206/11/2011
There are many families of carbon materials that can be used as active electrode materials, conductive additives and even current collectors. Supercapacitor performance can be enhanced by creating designed architectures, tailoring porosity and using exohedral nanostructures that are matched synergistically with appropriate electrolyte systems. By moving from trial-and-error tests to science-driven design of nanostructured carbon electrodes we can develop new materials and architectures to dramatically boost energy and power densities of electrochemical capacitors.
Gogotsi, Yury
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