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At least 19 records

Understanding the Role of Lithium Iodide in Lithium–Oxygen Batteries

Lithium–oxygen (Li–O 2 ) batteries possess a high theoretical energy density, which means they could become a potential alternative to lithium-ion batteries. Nevertheless, the charging process of Li–O 2 batteries requires much higher energy, due to the insulating nature of the discharge product. It has been revealed that the anion additive, lithium iodide (LiI), can tune the cell chemistry to form lithium hydroxide (LiOH) as the product and facilitate the kinetics during the charging process. Although numerous studies have been reported, the role of this additive is still under investigation. Herein, the recent advances focusing on the use of LiI in Li–O 2 batteries are reviewed, its catalytic behavior on discharge and charge is discussed, and its synergistic effect with water is understood. Here, the ambiguity existing among the studies are also revealed, and solutions to the current issues are introduced.

25 ENERGY STORAGE↗

Unveiling the Role of Lithium Iodide in Stabilizing Solid Interfaces in All-Solid-State Li Metal Batteries

A critical challenge in all-solid-state lithium metal batteries (ASSLMBs) is achieving a stable interface between the lithium metal anode and the solid electrolyte. Leveraging its success in Li/I 2 batteries, lithium iodide has garnered significant attentions for its potential to enhance interfacial stability and overall cell performance in ASSLMBs. Here, we elucidate the role of lithium iodide in stabilizing the solid interface in all-solid-state Li metal batteries with a Li argyrodite electrolyte, particularly focusing on its influence on lithium deposition behavior and interfacial evolution. Through in situ optical imaging, we demonstrate more uniform lithium deposition on an iodide-contained argyrodite electrolyte compared to a chloride-based counterpart. Complementary density functional theory calculations attribute improved lithium plating behavior to the enhanced lithiophilicity and better ionic conductivity of lithium iodide at the solid interface, effectively reducing localized current density. In conclusion, these findings provide useful insights into the mechanisms through which lithium iodide enhances the interfacial stability in ASSLMBs.

Anions↗

Metal halide arc discharge lamp having short arc length

A metal halide arc discharge lamp includes a sealed light-transmissive outer jacket, a light-transmissive shroud located within the outer jacket and an arc tube assembly located within the shroud. The arc tube assembly includes an arc tube, electrodes mounted within the arc tube and a fill material for supporting an arc discharge. The electrodes have a spacing such that an electric field in a range of about 60 to 95 volts per centimeter is established between the electrodes. The diameter of the arc tube and the spacing of the electrodes are selected to provide an arc having an arc diameter to arc length ratio in a range of about 1.6 to 1.8. The fill material includes mercury, sodium iodide, scandium tri-iodide and a rare gas, and may include lithium iodide. The lamp exhibits a high color rendering index, high lumen output and high color temperature.

Muzeroll, Martin E.↗

Method for forming thin composite solid electrolyte film for lithium batteries

A composite solid electrolyte film is formed by dissolving a lithium salt such as lithium iodide in a mixture of a first solvent which is a cosolvent for the lithium salt and a binder polymer such as polyethylene oxide and a second solvent which is a solvent for the binder polymer and has poor solubility for the lithium salt. Reinforcing filler such as alumina particles are then added to form a suspension followed by the slow addition of binder polymer. The binder polymer does not agglomerate the alumina particles. The suspension is cast into a uniform film.

Nagasubramanian, Ganesan↗

Method for forming thin composite solid electrolyte film for lithium batteries

A composite solid electrolyte film is formed by dissolving a lithium salt such as lithium iodide in a mixture of a first solvent which is a co-solvent for the lithium salt and a binder polymer such as polyethylene oxide and a second solvent which is a solvent for the binder polymer and has poor solubility for the lithium salt. Reinforcing filler such as alumina particles are then added to form a suspension followed by the slow addition of binder polymer. The binder polymer does not agglomerate the alumina particles. The suspension is cast into a uniform film.

Nagasubramanian, Ganesan↗

Self-Passivating Lithium/Solid Electrolyte/Iodine Cells

Robust lithium/solid electrolyte/iodine electrochemical cells that offer significant advantages over commercial lithium/ iodine cells have been developed. At room temperature, these cells can be discharged at current densities 10 to 30 times those of commercial lithium/iodine cells. Moreover, from room temperature up to 80 C, the maximum discharge-current densities of these cells exceed those of all other solid-electrolyte-based cells. A cell of this type includes a metallic lithium anode in contact with a commercial flexible solid electrolyte film that, in turn, is in contact with an iodine/ graphite cathode. The solid electrolyte (the chemical composition of which has not been reported) offers the high ionic conductivity needed for high cell performance. However, the solid electrolyte exhibits an undesirable chemical reactivity to lithium that, if not mitigated, would render the solid electrolyte unsuitable for use in a lithium cell. In this cell, such mitigation is affected by the formation of a thin passivating layer of lithium iodide at the anode/electrolyte interface. Test cells of this type were fabricated from iodine/graphite cathode pellets, free-standing solid-electrolyte films, and lithium-foil anodes. The cathode mixtures were made by grinding together blends of nominally 10 weight percent graphite and 90 weight percent iodine. The cathode mixtures were then pressed into pellets at 36 kpsi (248 MPa) and inserted into coin-shaped stainless-steel cell cases that were coated with graphite paste to minimize corrosion. The solid-electrolyte film material was stamped to form circular pieces to fit in the coin cell cases, inserted in the cases, and pressed against the cathode pellets with polyethylene gaskets. Lithium-foil anodes were placed directly onto the electrolyte films. The layers described thus far were pressed and held together by stainless- steel shims, wave springs, and coin cell caps. The assembled cells were then crimped to form hermetic seals. It was found that the solid electrolyte films became discolored within seconds after they were placed in contact with the cathodes - a result of facile diffusion of iodine through the solid electrolyte material (see figure).

Bugga, Ratnakumar↗

Chemical State of Surface Oxygen on Carbon and Its Effects on the Capacity of the Carbon Anode in a Lithium-Ion Battery Investigated

In a lithium-ion battery, the lithium-storage capacity of the carbon anode is greatly affected by a surface layer formed during the first half cycle of lithium insertion and release into and out of the carbon anode. The formation of this solid-electrolyte interface, in turn, is affected by the chemistry of the carbon surface. A study at the NASA Glenn Research Center examined the cause-and-effect relations. Information obtained from this research could contribute in designing a high-capacity lithium-ion battery and, therefore, small, powerful spacecraft. In one test, three types of surfaces were examined: (1) a surface with low oxygen content (1.5 at.%) and a high concentration of active sites, (2) a surface with 4.5 at.% -OH or -OC type oxygen, and (3) a surface with 6.5 at.% O=C type oxygen. The samples were made from the same precursor and had similar bulk properties. They were tested under a constant current of 10 mA/g in half cells that used lithium metal as the counter electrode and 0.5 M lithium iodide in 50/50 (vol%) ethylene carbonate and dimethyl carbonate as the electrolyte. For the first cycle of the electrochemical test, the graph describes the voltage of the carbon anode versus the lithium metal as a function of the capacity (amount of lithium insertion or release). From these data, it can be observed that the surface with low oxygen and a high concentration of active sites could result in a high irreversible capacity. Such a high irreversible capacity could be prevented if the active sites were allowed to react with oxygen in air, producing -OH or -OC type oxygen. The O=C type oxygen, on the other hand, could greatly reduce the capacity of lithium intercalation and, therefore, needs to be avoided during battery fabrication.

Hung, Ching-Cheh↗

Regenerative Solid Interfaces Enhance High-Performance All- Solid-State Lithium Batteries

All-solid-state Lithium batteries (ASSLBs) have gained widespread attention in recent years. However, their performance is still largely limited by the poor transport properties and stability of the solid-solid interfaces (SSIs). In this study, we report a new strategy for creating a reversible interface with good conductivity and self-adaptive mechanical properties for high-performance all-solid-state lithium batteries (ASSLBs). The interface is formed in situ from nanosized lithium iodide (LiI), a component of the solid-state electrolyte (SSE), which flows plastically along the SSE interfaces under high pressure due to its high ductility. Moreover, LiI segregates and enriches along the Li/SSE interfaces, reversibly enhancing Li plating/stripping due to its lithophilicity and high ionic conductivity. This dynamic LiI interface enables stable operation of metallic Li anode (>1000 h) at high current densities and elevated temperatures, and long-term cycling of all-solid-state Li-sulfur batteries (>250 cycles) with high sulfur utilization rate (>1400 mAh g-1) and areal capacity (>2 mAh cm-2). This study reveals a unique role of LiI in building robust SSIs and provides new insights into the design of novel SSEs and interfaces for high-performance ASSLBs.

Yu, Zhaoxin↗

Dual Function Solid State Battery with Self-Forming Self-Healing Electrolyte and Separator (Final Scientific/Technical Report)

Over the course of this program, we have demonstrated an improved rechargeable Li/I2 battery with reduced impedance, improved cyclability, improved Coulombic Efficiency, and the ability to “self-heal” during shorting events. Multi-year efforts have led to the development and improvements in the composition, fabrication, and preparation of the solid state electrolyte, the role of the interface, and design of appropriate test conditions. These investigations have led to significant improvements in Coulombic efficiency. By systematic development of a composite solid state electrolyte, this system is able to self-form upon charge, thus lending itself to long shelf life before use. The initial project objective was to demonstrate a solid-state rechargeable battery based on a Li-metal anode and iodine cathode with a self-forming, self-healing electrolyte and separator with high gravimetric and volumetric energy density. The final deliverables of this project build on a multi-year effort beginning with materials development and design to generate a suitable solid state electrolyte composite with demonstrated higher ionic conductivity compared to the baseline (LiI). Development in cell design and interface modification leading to the generation of rechargeable solid electrolyte cells with Coulombic efficiency improvements of ~3X over initial tests, as well as demonstration of self-healing behavior, where the cells retained their ability to continue extended cycling after shorting events. The hypothesis put forward as part of the initial concept for the project was that the cell chemistry would be self-healing. For example, if a lithium dendrite formed during charge of the cell and reached the iodine cathode, the reaction of the lithium dendrite with the iodine would consume the tip of the dendrite to form lithium iodide, more of the solid electrolyte. The formation of the solid electrolyte would allow the cell to recover and continue to function. This type of self-healing during cycling has been demonstrated and has the potential to improve on safety considerations that stem from shorting events in other Li- containing systems.

25 ENERGY STORAGE↗

Molten fluid apparatus with solid non-brittle electrolyte

A battery includes a fluid negative electrode and a fluid positive electrode separated by a solid electrolyte at least when the electrodes and electrolyte are at an operating temperature. The solid electrolyte includes ions of the negative electrode material forming the fluid negative electrode and has a softness less than beta-alumina solid electrolyte (BASE) ceramics. In one example, the fluid negative electrode comprises lithium (Li), the fluid positive electrode comprises sulfur (S) and the solid electrolyte comprises lithium iodide (LiI).

Vissers, Daniel R.↗

Molten fluid apparatus with solid non-brittle electrolyte

A battery includes a fluid negative electrode and a fluid positive electrode separated by a solid electrolyte at least when the electrodes and electrolyte are at an operating temperature. The solid electrolyte comprises a salt formed by ions of the negative electrode material forming the fluid negative electrode. In one example, the fluid negative electrode comprises lithium (Li), the fluid positive electrode comprises sulfur (S) and the solid electrolyte comprises lithium iodide (LiI).

Vissers, Daniel R.↗

Chemically Generated Liquid Sulfur Droplets at Room and Subzero Temperatures

The liquid phase of sulfur has been observed at room temperature, resulting from the electrochemical oxidation of polysulfides, a process occurring on the electrodes and influenced by the electrode materials. However, such electrode-dependent behavior of liquid sulfur has constrained its use in battery applications, driving research for alternative processes. This paper introduces an approach to generating liquid sulfur at both room and subzero temperatures through chemical reactions independent of the substrate material. We demonstrate that using a redox mediator, polysulfides can be chemically oxidized into liquid sulfur droplets in the electrolyte close to but away from the electrode. This pathway can generate liquid sulfur at room and subzero temperatures of −15 °C, 130 °C below sulfur’s melting temperature (115 °C). The chemically generated liquid sulfur further enriches the lithium–sulfur-electrolyte material systems, potentially creating opportunities for high-energy lithium–sulfur and other metal–sulfur batteries.

liquid sulfur↗

Refractive field correctors for the Starlab ultraviolet telescope

Field correctors for a one-meter, f/15 cassegrainian telescope were designed as part of a NASA-funded study of an astronomical obervatory on board of the Space Shuttle. By means of a Gasgoigne corrector and a biconcave field flattener, astigmatism and field curvature are corrected in a 0.6 deg field. Applicable wavelength ranges are limited by chromatic aberrations. The upper wavelength is selected to match a photocathode response limit. The lower wavelength limit is defined by a filter. Examples of usable wavelength ranges are: 210 nm - 1100 nm (multialkali photocathode, fused-silica corrector elements), 177 nm - 320 nm (cesium telluride photocathode, calcium fluoride correctors); and possibly 134 nm - 190 nm (cesium iodide photocathode, lithium fluoride correctors). Residual rms lateral color is smaller than 0.02 arc sec, and axial color is smaller than 0.25 arc sec (blur diameter at the ends of the wavelength range). The correctors introduce a small amount of coma. This is compensated by adjustment of the conic constants of the telescope mirrors.

Bottema, M.↗

Microclusters of Kinked Silicon Nanowires Synthesized by a Recyclable Iodide Process for High-Performance Lithium-Ion Battery Anodes

Silicon shows great promise as a high-capacity anode material for lithium-ion batteries. Nanostructuring silicon minimizes the impact of fracturing during charging and discharging. However, synthesizing nanostructured silicon typically requires complicated procedures with high manufacturing costs. Additionally, these complicated procedures typically have poor secondary particle formation, a requirement to achieve a high tap density. Here, a cost-effective synthesis procedure which generates nearly ideal secondary particle clusters of nanostructured silicon is developed. The cost-effectiveness is a result of the in operando generation of silicon iodide from iodine gas and low-grade silicon microparticle. Decomposition of silicon iodide into crystalline silicon and iodine gas enables recycling of the iodine gas, allowing for near full reutilization of iodine in the following cycles. Additionally, the optimal nanostructures and microstructures of silicon synthesized by the recyclable iodide decomposition reaction enables 83.6% capacity retention over 1000 cycles. The good performance is a result of well-maintained morphology during cycling, enabling reutilization of the solid electrolyte interphase.

25 ENERGY STORAGE↗

Computational and experimental analysis of structural and Thermophysical properties of LiX-KX (X = chloride, iodide, or bromide) molten salts

Molten salts containing lithium (Li) and potassium (K) halides, including chlorides (Cl), bromides (Br), and iodides (I), are pivotal in advanced technological applications including nuclear reactor technologies, thermal batteries, and industrial pyrochemical processes. Despite their significance, the availability of the temperature-dependent structural and thermophysical properties of these molten salts remain scarce. Here, this study addresses this knowledge gap by predicting and measuring the key properties such as coordination number, radial distribution function, density, heat capacity, and volumetric thermal expansion of molten LiI-KI, LiBr-KBr and LiCl-KCl eutectic mixtures. Utilizing ab initio molecular dynamics (AIMD) simulations, we predict these properties of LiX-KX (X=Br,I, Cl) across various temperatures, with chlorides as a benchmark. Experimental measurements using Archimedes methods and Differential Scanning Calorimetry validate the densities and heat capacities of these molten salts. Our comprehensive analysis of the structural and thermophysical properties provides critical insights into the behavior of these molten salts at various temperatures, enhancing the understanding necessary for their application in advanced technologies.

36 - MATERIALS SCIENCE↗

Diffraction imaging (topography) with monochromatic synchrotron radiation

Structural information of special interest to crystal growers and device physicists is now available from high resolution monochromatic synchrotron diffraction imaging (topography). In the review, the importance of superior resolution in momentum transfer and in space is described, and illustrations are taken from a variety of crystals: gallium arsenide, cadmium telluride, mercuric iodide, bismuth silicon oxide, and lithium niobate. The identification and understanding of local variations in crystal growth processes are shown. Finally, new experimental opportunities now available for exploitation are indicated.

Steiner, Bruce↗