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At least 19 records

Template Assisted Lithium Superoxide Growth for Lithium-Oxygen Batteries

Developing batteries with energy densities comparable to internal combustion technology is essential for a worldwide transition to electrified transportation. Li-O2 batteries are seen as the ‘holy grail’ of battery technologies since they have the highest theoretical energy density of all battery technologies. Current lithium-oxygen (Li-O2) batteries suffer from large charge overpotentials related to electronic resistivity of the insulating lithium peroxide (Li2O2) discharge product. One potential solution is the formation and stabilization of a lithium superoxide (LiO2) discharge intermediate that exhibits good electronic conductivity. However, LiO2 is reported to be unstable at ambient temperature despite its favorable formation energy at -1.0 eV/atom. In this paper, based on our recent work on the development of cathode materials for aprotic lithium oxygen batteries including two intermetallic compounds, LiIr3 and LiIr, that are found to form good template interfaces with LiO2, a simple goodness of fit R factor to gauge how well a template surface structure can support LiO2 growth is developed. The R factor is a quantitative measurement to calculate the geometric difference in the unit cells of specific Miller Index 2D planes of the template surface and LiO2. Using this as a guide, the R factors for LiIr3, LiIr, and La2NiO4+, are found to be good. This guide is attested by simple extension to other noble metal intermetallics with electrochemical cycling data including LiRh3, LiRh, and Li2Pd. Finally, the template concept is extended to main group elements and the R factors for LiO2 (111) and Li2Ca suggest that Li2Ca is a possible candidate for the template assisted LiO2 growth strategy.

Intermetallics↗

Understanding the Cathode Electrochemistry of Humidified Solid‐State Lithium‐Oxygen Batteries

Lithium-oxygen batteries (LOBs) possess a high theoretical energy density, making them potential candidates for next-generation energy storage. However, challenges such as reactive oxygen species-induced component degradation hinder their practical use. Inorganic solid-state electrolytes offer an alternative to degradation-prone aprotic electrolytes, while also protecting lithium anodes from potential atmospheric reactants. Here, this study explores the cathode electrochemistry of solid-state LOBs using humidified oxygen, which forms an aqueous catholyte during initial cycling, thereby improving cathode-electrolyte contact. To quantitatively analyze the cathode electrochemistry, a ‘Humidity-Incorporated’ Differential Electrochemical Gas Monitoring System (HiDEMS) is developed to control humidity and monitor gas consumption and evolution in real time. When studying a Li-O 2 cell that employs a NASICON-type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) solid electrolyte and a porous carbon cathode, a shift in discharge products from Li 2 O 2 to LiOH is observed over repeated cycles. While Li 2 O 2 evolves O 2 during charging, LiOH oxidation leads to minimal O 2 release and increased CO 2 production, originating from oxidation of carbon electrodes. Further, dissolution of Al and P from LATP is observed, likely driven by the formation of the alkaline catholyte. The findings highlight the need for carbon-free cathode materials and more stable solid-state conductors to minimize side reactions and improve rechargeability in humidified solid-state Li-O 2 batteries.

LATP degradation↗

Analysis of Degradation and Electrochemical Behavior of Lithium–Oxygen Batteries under Lean Electrolyte Conditions

Lithium-oxygen batteries have garnered much attention in the past decades due to their high energy density and active material abundancy. Decreasing the electrolyte volume is critical to achieving a high energy density for practical applications. Recent works have demonstrated a serious performance limitation at lower electrolyte fillings. Here, in this work, we study specifically the difference between flooded and lean electrolyte lithium-oxygen batteries by systematically tracing the source of performance degradation. We find that the key contributor to the decrease in performance under lean electrolyte conditions stems from the lithium metal anode rather than the cathode. Solid electrolyte interphase (SEI) compositionally appears to be the same from X-ray photoelectron spectroscopy but the coverage is less uniform, and impedance is much higher under lean electrolyte conditions. Such an effect likely produced the observed poorer cycle performance at 10 μL cm -2 (similar to 28% cathode's pore volume filled) vs 100 μL cm -2 (278% of cathode's pore volume) at a capacity of 1.0 mAh cm -2 (0.1 mAh cm -2 ) using an electrolyte composition of 1 M LiTFSI in TEGDME.

Córdoba, Daniel [Argonne National Laboratory (ANL)↗

Graphene-supported single atom catalysts for high performance lithium-oxygen batteries

The optimal choice of d-block metals in single atom catalysts (SACs) is crucial for designing efficient electrocatalysts for activating the Oxygen reduction reaction (ORR)/ Oxygen evolution reaction (OER) in lithiumoxygen batteries (LOBs). Herein, we used the Quantum Mechanics methods to understand the origin of reactivity for a series of 16 d-block metals supported on nitrogen-doped graphene as SACs for ORR and OER in LOBs. Based on the Gibbs free energy calculations, we found that among the 16 SACs investigated, Zn-SAC exhibits the highest electrochemical activity with the lowest overpotential of 0.17 V. Here we then used machine learning (ML) to develop an intrinsic descriptor, phi, that correlates the catalytic activity with electronic and chemical properties of the catalytic centers at the M-N 4 active site on graphene surface. We established a linear relationship between phi and the catalytic activity that provides guidance for designing efficient SACs for electrocatalysis in LOBs. To validate these predictions, we report electrochemical measurements showing that Zn-SAC exhibits an ultra-stable cyclability with reduced overpotentials over Mo-SAC and nitrogen-doped graphene (NG), confirming our theoretical prediction. This fundamental work provides a deep understanding on the rational design of efficient SACs for OER/ ORR in LOBs.

25 ENERGY STORAGE↗

LiON: Lithium Oxygen Batteries for NASA Electric Aircraft

Li-Air batteries are a unique fit for electric aircraft due to their high theoretical energy densities and their potential to leverage on-board oxygen systems. Electrolytes are the limiting factor for advancing this technology. We will investigate novel "electrolyte engineering" concepts to enable Li-Air batteries with high practical energy densities, rechargeability and safety. New stable electrolytes will be designed and fabricated for Li-Air batteries and tested in an electric flight. An unprecedented "Dream Team" of experts from NASA, DOE, academia and industry will tackle this problem.

Lawson, John↗

Catalytic cathode for a lithium-oxygen battery

A metal-air battery includes an anode; a low-dimensional catalyst cathode; and an electrolyte; wherein: the low-dimensional catalyst cathode comprises a functional metal layer on a carbon support overcoated with a catalyst layer; the electrolyte comprises an aprotic solvent that is an ether-based solvent, a fluorinated ether-based solvent, an oligo (ethylene oxide) solvent, or a mixture of any two or more thereof; and the electrolyte is free of carbonate solvents.

25 ENERGY STORAGE↗

Solvents and catalyst preparations for lithium-oxygen batteries

An electrochemical device includes a lithium anode having a red poly(benzonitrile) coating covering at least a portion of the anode; a separator and an air cathode comprising reduced graphene oxide over gas diffusion layer; and an electrolyte comprising an ether solvent, benzonitrile, and a lithium salt.

Wang, Hsien-Hau↗

Solvents and catalyst preparations for lithium-oxygen batteries

An electrochemical device includes a lithium anode having a red poly(benzonitrile) coating covering at least a portion of the anode; a separator and an air cathode comprising reduced graphene oxide over gas diffusion layer; and an electrolyte comprising an ether solvent, benzonitrile, and a lithium salt.

Wang, Hsien-Han↗

A lithium oxygen secondary battery

Some recent work on a lithium-oxygen secondary battery is reported in which stabilized zirconia oxygen vacancy conducting solid electrolytes were used for the effective separation of respective half-cell reactions. The electroactive material consisted of alloys possessing the general composition Li(x)FeSi2 immersed in a ternary molten salt comprising LiF, LiCl, and Li2O. The manufacture of the cell is described, and discharge-current voltage curves for partially charged cells are shown and discussed. A galvanostatic IR free-changing curve and an IR-free charge-discharge curve are also shown.

Semkow, Krystyna W.↗

Discharge Rate‐Driven Li 2 O 2 Growth Exhibits Unconventional Morphology Trends in Solid‐State Li‐O 2 Batteries

Solid-state lithium oxygen batteries (LOBs) are known for their enhanced safety, higher electrochemical stability, and improved energy density compared to liquid-state LOBs. However, the investigation of solid-state LOBs is limited with little understanding of their discharge and charge processes. In this work, a polymer-based solid-state LOB is used to investigate the effect of discharge rate on lithium peroxide (Li 2 O 2 ) formation, the oxygen evolution reaction (OER), and cycle performance. Notably, we observe a counterintuitive trend: Li 2 O 2 particle size increases with increasing discharge current density, in contrast to liquid systems. This behavior arises from inherent space charge layers that restrict Li⁺ transport under high current, and spatially heterogeneous active sites at the solid electrolyte–cathode interface, directly evidenced by small angle X-ray scattering (SAXS), which govern nucleation accessibility and promote site-selective Li 2 O 2 growth. Furthermore, higher current densities improve ORR and OER efficiency but accelerate anode degradation, while lower currents promote side reactions. These opposing effects result in a trade-off that defines an optimal discharge rate (0.1 mA cm -2 ) for maximizing cycle life. This study provides a new mechanistic perspective on discharge-driven processes in solid-state LOBs and offers practical guidelines for performance optimization in future high-energy battery systems.

Discharge current density↗

Atomic-scale vacancy engineering unlocks basal-plane catalytic activity in metallic WSe 2 for reversible oxygen electrocatalysis

Two-dimensional metallic transition metal dichalcogenides offer high electrical conductivity and large surface areas for electrocatalysis, yet their inherent basal planes are catalytically inert. Here, we present an atomic-scale vacancy engineering strategy to activate the basal surfaces of metallic WSe 2 for reversible oxygen electrocatalysis. This approach, based on intentionally designed substitutional metal doping, promotes the spontaneous formation of selenium vacancies while preserving the metallic 1 T′ phase, thereby creating highly reactive and oxygen-affinitive sites. Density functional theory calculations reveal that these vacancy-mediated metal complexes dramatically lower the energy barriers for initial oxygen adsorption, enabling dissociative oxygen adsorption. Operando and ex-situ spectroscopic analyses confirm that vacancy-mediated metal complexes transform into dynamic Se/W-oxide intermediates under operating conditions. Se/W-oxides on the surface experimentally and theoretically prove electrocatalytic activity and reversibility. Applying this strategy in lithium–oxygen batteries, the basal-plane activated WSe 2 shows high discharge capacities (9868 mA h g −1 , corresponding to 3947 mA h g$^{-1}_{cathode}$), impressive cycle retention over 550 cycles at 1000 mA h g −1 , and outstanding rate–capability over a wide current–density range (100–3000 mA g −1 ) during 256 cycles.

2D materials↗

Physics-Based Modeling and Simulation of Emerging Battery Technologies for Aerospace

Recently there is a growing interest in the aviation sector to reduce air and noise pollution. Electrochemical energy storage devices such as batteries coupled with a distributed electric propulsion system can reduce noise concerns as well as emissions and allow the concept of Urban Air Mobility to come to fruition. The battery performance needs to improve considerably compared from current state-of-art Li-ion battery (about 200Wh/Kg) to realize all-electric passenger jet for short flights (up to 690 miles). NASA is exploring lithium-oxygen battery chemistry to power hybrid (battery powered electrical system) and all-electric aircraft for short distance and long-distance flights. Li-O2 is one of the advanced Li-ion technologies that promise to provide specific energy of more than 750Wh/Kg. For this presentation, we present our work on improving power density of Li-O2 batteries through the use of multiphysics simulations. Next, a path is outlined to port these model to simulate performance for a new battery chemistry for space application, Li-CO2. Li-CO2 uses carbon dioxide as the active material instead of oxygen. Although this technology is in its early development, the offers two benefits: it can be used as a CO2 scrubber, as oxygen is one of the by-products on charging, and as a backup or a standalone battery for various Mars or Venus missions, where the carbon dioxide content in the atmosphere is high and need battery to operate at higher temperatures.

Mehta, Mohit↗

Ultrahigh Mass Loading Batteries with Holey Graphene-Enabled Dry-Pressed Cathode Architectures

Holey graphene is a structural derivative of graphene with arrays of nanometer-sized, through-thickness holes across the lateral surface of the atomically thin nanosheet. It has been widely acknowledged that the presence of holes improves ion transport through the graphene planes, making holey graphene an ideal electrode material for electrochemical energy storage. We recently discovered another unique attribute of holey graphene in that it can be directly compressed from powder into electrode in a single step without the use of solvent or binder. In addition to neat holey graphene electrodes, composite electrodes with holey graphene as an ultralightweight scaffold host filled with various active materials can also be readily prepared in a similar solvent-free and binder-free fashion. The active materials can be metal-containing catalysts for lithium-oxygen batteries, lithium-ion battery electrode materials, or high energy density components such as sulfur. Compared to the conventional slurry-based process, the dry-press method is comparably much more suitable toward the facile and scalable preparation of ultrahigh mass loading electrodes with ultrahigh areal capacities.

holey graphene, cathode scaffold, lithium metal, h↗

The electrochemical generation of useful chemical species from lunar materials

The current status of work on an electrochemical technology for the simultaneous generation of oxygen and lithium from a Li2O containing molten salt (Li2O-LiCl-LiF) is discussed. The electrochemical cell utilizes an oxygen vacancy conducting solid electrolyte, yttria-stabilized zirconia, to effect separation between the oxygen evolving and lithium reduction half-cell reactions. The cell, which operates at 700 to 800 C, possesses rapid electrode kinetics at the lithium-alloy electrode with exchange current density values being greater than 60 mA/sq cm, showing high reversibility for this reaction. When used in the electrolytic mode, lithium produced at the negative electrode would be continuously removed from the cell for later use (under lunar conditions) as an easily storable reducting agent (compared to H2) for the chemical refining of lunar ores via the general reaction: 2Li + MO yields Li2O + M where MO represents a lunar ore. Emphasis to this time has been on the simulated lunar ore ilmenite (FeTiO3), which we have found becomes chemically reduced by Li at 432 C. Furthermore, both Fe2O3 and TiO2 have been reduced by Li to give the corresponding metal. This electrochemical approach provides a convenient route for producing metals under lunar conditions and oxygen for the continuous maintenance of human habitats on the Moon's surface. Because of the high reversibility of this electrochemical system, it has also formed the basis for the lithium-oxygen secondary battery. This secondary lithium-oxygen battery system posses the highest theoretical energy density yet investigated.

Tsai, Kan J.↗

Novel Electrolytes for Use in Li-Air Batteries for NASA Electric Aircraft

Li-Air batteries are a unique fit for electric aircraft due to their high theoretical energy densities and their potential to leverage on-board oxygen systems. The electrolyte and cathode are the limiting factors for advancing this technology. We are investigating novel "electrolyte and cathode engineering" concepts to enable Li-Air batteries with high practical energy densities, rechargeability and safety. New stable electrolytes and cathodes are being designed and fabricated for Li-Air batteries. An array of various electrolytes were screened and analyzed using NMR and DEMS analysis techniques to understand the fundamental decomposition mechanisms at the cathode surface and within the porous polymer separator. (NMR) spectroscopy has yielded mechanistic insight into decomposition pathway, which is vital to the development of future stable electrolyte candidates. Thus far, five new electrolytes have been screened with 2 showing promising results.

Li-Air↗

The electrochemical generation of useful chemical species from lunar materials

Electrochemical cells have been fabricated for the simultaneous generation of oxygen and lithium from a Li2O containing molten salt (Li2O-LiCl-LiF). The cell utilizes an oxygen vacancy conducting solid electrolyte, yttria-stabilized zirconia (YSZ), to effect separation between oxygen evolving and lithium reduction half-cell reactions. The cell, which operates at 700 to 850 C, possesses rapid electrode kinetics at the lithium-alloy electrode with exchange current density (i sub o) values being greater than 60mA sq cm. When used in the electrolytic mode, lithium produced at the negative electrode would be continuously removed from the cell for later use (under lunar conditions) as an easily storable reducing agent (compared to H2) for the chemical refining of lunar ores. Because of the high reversibility of this electrochemical system, it has also formed tha basis for the lithium oxygen secondary battery system which possesses the highest theoretical energy density yet investigated.

Tsai, Kan J.↗