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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 433 records · Page 24
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Probing the Effect of Electrode Thermodynamics on Reaction Heterogeneity in Thick Battery Electrodes

Thick electrodes present a viable strategy for enhancing energy density and reducing manufacturing costs of lithium-ion batteries. However, reaction heterogeneity during cycling compromises their rate capability and cycle life. While this nonuniformity is commonly attributed to sluggish charge transport, it is demonstrated here that the thermodynamic properties of the electrode material play an equally critical role. Through combined X-ray fluorescence microscopy and absorption near-edge structure spectroscopy, reaction distributions in LiFePO 4 (LFP) and LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC) thick electrodes with matched porosity and tortuosity are compared. LFP electrodes develop pronounced depth-oriented state-of-charge (SOC) gradients that worsen with increasing discharge rates, whereas NMC maintains much more uniform SOC distributions under such conditions. This difference originates from their distinct SOC dependence of equilibrium potentials and is quantifiable through a dimensionless “reaction uniformity” number. Intriguingly, LFP thick electrodes also exhibit lateral SOC variations that strengthen during slow discharge. In conclusion, the enhanced reaction uniformity in NMC correlates with better active material utilization and slower capacity fade than LFP, highlighting electrode thermodynamics as a key design consideration for thick electrodes.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Interfacial Issues and Modification of Solid Electrolyte Interphase for Li Metal Anode in Liquid and Solid Electrolytes

Abstract The high energy density required for the next generation of lithium batteries will likely be enabled by a shift toward lithium metal anode from the conventional intercalation‐based anode such as graphite. However, several critical challenges for Li metal originate from its highly reactive nature and the hostless reaction of deposition and stripping impede the practical use of Li metal as an anode. The role of the solid electrolyte interphase (SEI) is very important for the Li metal anode where the SEI must protect the dynamically changing surface of the Li metal. Since the SEI‐generating reaction mechanisms for the two different electrolyte systems, liquid and solid, are considerably different, the SEI layers formed between the Li metal and the electrolytes in the two electrolyte systems have substantially different properties, causing different interfacial issues. Inhibition of the interfacial problems requires different strategies to reinforce the SEI layer for each of the electrolyte systems. However, the differences in the two electrolyte systems have not been clearly compared in the prior literature. In this report, the interfacial issues for the two different electrolyte systems are compared and different strategies for SEI modification are provided to overcome the issues.

25 ENERGY STORAGE↗
DOE OSTI2025

Characterizing Disorders Within Cathode Materials of Lithium‐Ion Batteries

The demand for developing high-energy density cathode materials has been increasing. The energy densities of cathode materials have been improved by adapting structural deviation from the ideal fully ordered α-NaFeO2 type, but that led to limitations in terms of structural stability and safety. Although disorders in cathode materials are closely related to their electrochemical properties, unfortunately, characterizing the disorder itself in cathode materials has been challenging due to its complex parasitic reaction and strong correlation with other disorders occurring during charge/discharge. In this review, we categorize various disorders by their scales of ordering from short-range to long-range. We addressed the principles of various characterization tools to figure out how they can help to identify the structural disorder in cathode materials. Specifically, we focused on the underlying principles of each characterization technique to correlate different disorder-driven phenomena through several case studies. It underscores the substantial importance of disorder-property relationships and the corresponding characterization methods, which can provide novel research strategies for developing high-energy density cathode materials with decent structural stability.

Lee, Hakwoo↗
DOE OSTI2020

Dry-pressed lithium nickel cobalt manganese oxide (NCM) cathodes enabled by holey graphene host

There is an increasing demand for electric vehicle batteries with higher energy densities that can be manufactured with low cost utilizing environmentally friendly processes. Lithium nickel cobalt manganese oxides (NCM), such as LiNi(0.5)Co(0.2)Mr(0.3)O(2) (NCM523), are commonly used in commercial lithium ion batteries for electric vehicle applications. These cathodes are typically fabricated using environmentally hazardous, energy intensive, and time-consuming solvent-based slurry casting processes. Polymeric binders, also required for cathode preparation, add weight and can undergo parasitic reactions during battery cycling. Here we report a facile, solvent-free, binder-free, and rapid cold-press electrode fabrication process to prepare high mass loading NCM cathodes within minutes. This process is enabled by the use of holey graphene, a unique lightweight, compressible carbon nanomaterial that serves as both a binder and an electrically conductive matrix. NCM cathodes fabricated by this method are stable and exhibit good active material utilization. A significant advantage for the dry-press process is that the electrode mass loadings can be readily increased simply by adding more composite powder to the compression molding die, resulting in improved areal capacities that are attractive for applications requiring high energy per unit footprint. (C) 2020 Elsevier Ltd. All rights reserved.

25 ENERGY STORAGE↗
DOE OSTI2021

Roles of Mn and Co in Ni-rich layered oxide cathodes synthesized utilizing a Taylor Vortex Reactor

It is reported that layered oxides, composed of nickel, manganese, and cobalt (NMC), are sought after as cathode materials which provide improved energy density, cycle life, and safety in commercial lithium ion batteries (LIBs). Increasing Ni contents higher than 80% can provide even higher practical discharge capacities >200 mAh/g and similar to ~4 V discharge potential vs Li/Li + , making them promising cathodes for next generation LIBs. However, rapid capacity fade during cycling and heat-related safety concerns are delaying their successful transition to industry. We report systematic performance optimization of LiNiO 2 , LiNi 0.9 Mn 0.1 O 2 , and LiNi 0.9 Co 0.1 O 2 high Ni layered oxide cathodes synthesized by utilizing a Taylor Vortex Reactor. Co-free LiNi 0.9 Mn 0.1 O 2 cathode showed 200 mAh/g highest discharge capacity at 0.1 C rate with 84% retention after 103 cycles at 0.3C rate while LiNi 0.9 Co 0.1 O 2 cathode showed higher initial but poor cycle life (225 mAh/g highest discharge capacity at 0.1C rate with only 56% capacity retention after 103 cycles at 0.3 C rate. Synchrotron based X-ray diffraction (SXRD), X-ray absorption spectroscopy (XAS) and focused ion beam (FIB) imaging of pristine and cycled cathodes after 103 cycles provided important information on degradation mechanism. The roles of Mn and Co on layered structure formation, charge balance, cationic mixing, and electrochemical performance were elucidated using the crystallographic information from XRD refinement and electronic state analysis from XAS providing valuable information to design future Ni-rich layered oxide cathodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Three-Dimensional Microbatteries beyond Lithium Ion

Ubiquitous implementation of microelectronics in microelectromechanical systems requires stable power supplies and necessitates development of on-chip miniature power sources, such as microbatteries. However, conventional thin-film batteries exhibit limited surface area and sluggish diffusion kinetics with insufficient energy and power density. In contrast, three-dimensional (3D) beyond-lithium (sodium, zinc, aluminum, etc.) battery architectures can significantly enhance the areal energy and power and meanwhile maintain the low-cost mass production. Despite this, the future of beyond-lithium systems is being questioned as they each present shortcomings. In this Comment, we discuss scientific advancements in reaction kinetics control, electrochemical stability improvements, and reaction mechanism understandings in 3D beyond-lithium battery systems, and finally, call for intensive research effort to address the challenges and develop strategies that can pave the way toward their commercialization.

25 ENERGY STORAGE↗
DOE OSTI2022

The Evolution of LiNi 0.5 Mn 0.3 Co 0.2 O 2 Particle Damage from Fast Charging in Optimized, Full Li-Ion Cells

Fast charging batteries are critical to the widespread adoption of electric vehicles to compete with refueling times of combustion-based vehicles. In the near term, adapting current commercial battery technologies to perform better under fast charging conditions through engineering optimizations will greatly expedite the process while exploratory fast-charging electrode materials are being pursued. To do so, the degradation modes in optimized Li-ion batteries need to be completely explored to understand fast charging limits while maintaining a high energy density and a long cycle life. While lithium plating on graphite still remains a challenge, cathode degradation also plays a key role in battery performance. In this work, we used nano- and micro-X-ray computed tomography to characterize the mechanical degradation of LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532) in optimized Li-ion batteries cycled at three rates, 1C, 6C, and 9C, and at different stages of cycle life, 225 and 600 cycles. We report despite using a conservative upper voltage cutoff limit aimed to minimize extensive cathode degradation, higher charging rates and increased cycling caused the polycrystalline NMC532 particles to fracture and pulverize, which likely drives cathode capacity fade and contributes to the decrease in overall cell performance.

25 ENERGY STORAGE↗
DOE OSTI2021

X-ray Nanoimaging of Crystal Defects in Single Grains of Solid-State Electrolyte Li 7–3x Al x La 3 Zr 2 O 12

All-solid-state lithium batteries promise significant improvements in energy density and safety over traditional liquid electrolyte batteries. The Al-doped Li 7 La 3 Zr 2 O 12 (LLZO) solid-state electrolyte shows excellent potential given its high ionic conductivity and good thermal, chemical, and electrochemical stability. Nevertheless, further improvements on electrochemical and mechanical properties of LLZO call for an in-depth understanding of its local microstructure. Here, we employ Bragg coherent diffractive imaging to investigate the atomic displacements inside single grains of LLZO with various Al-doping concentrations, resulting in cubic, tetragonal, and cubic-tetragonal mixed structures. We observe coexisting domains of different crystallographic orientations in the tetragonal structure. We further show that Al doping leads to crystal defects such as dislocations and phase boundaries in the mixed- and cubic-phase grain. This study addresses the effect of Al doping on the nanoscale structure within individual grains of LLZO, which is informative for the future development of solid-state batteries.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2024

Electro-Chemo-Mechanical Evolution at the Garnet Solid Electrolyte–Cathode Interface

Solid-state batteries promise higher energy density and improved safety compared with lithium-ion batteries. However, electro-chemomechanical instabilities at the solid electrolyte interface with the cathode and the anode hinder their large scale implementation. Here, in this study, we focus on resolving electro-chemo-mechanical instability mechanisms and their onset conditions between a state-of-the-art cathode, LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622), and the garnet Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte. We used thin-film NMC622 on LLZO pellets to place the interfacial region within the detection depth of the X-ray characterization techniques. The experimental probes of the near-interface region included in operando X-ray absorption spectroscopy and ex situ focused ion beam scanning electron microscopy. Electrochemical degradation was not observable during cycling at room temperature with 4.3 V versus Li/Li + charge voltage cutoff, or with stepwise potentiostatic hold up to 4.1 V versus Li/Li + . In contrast, secondary phases including reduced transition metal species (Ni 2+ , Co 2+ ) were found after cycling up to 4.3 V versus Li/Li + at 80 °C and during potentiostatic hold at 4.3 V versus Li/Li + (Ni 2+ ). Intergranular cracks between NMC622 grains and delamination at the NMC622|LLZO interface occurred readily after the first charge. These interface reaction products and mechanical failure lowered the capacity and cell efficiency due to partial loss of the NMC622 phase, partial loss of contact at the interface, and a higher polarization resistance. Electrochemical instability between delithiated NMC622 and LLZO could be mitigated by using a low charge voltage cutoff or cycling at lower temperature. Ways to engineer the mechanical properties to avoid crack deflection and delamination at the interface are also discussed for enhancing mechanical stability.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Operando video microscopy of Li plating and re-intercalation on graphite anodes during fast charging

Despite the demand for fast-charging lithium (Li)-ion batteries, high-energy-density batteries with thick graphite anodes are limited by Li plating when charging at >4C rates. In this work, plan-view operando video microscopy is applied on >3 mA h cm –2 calendared graphite electrodes to study the dynamic evolution of local state-of-charge (SoC) and Li plating during fast charging. This technique allows for visualization of the spatial heterogeneity in SoC across the electrode, nucleation and growth of Li filaments, Li re-intercalation into graphite, “dead Li” formation, and SoC equilibration. The operando microscopy analysis is complemented by ex situ imaging of through-plane gradients in SoC to gain a three-dimensional visualization of spatial heterogeneity. We demonstrate that (1) Li plating preferentially nucleates on the graphite particles that lithiate fastest during fast charging; (2) the onset of Li plating correlates with the local minimum of the graphite electrode potential; (3) galvanic corrosion currents are responsible for Li re-intercalation, dead Li formation, and SoC re-equilibration after fast charging; and (4) electrochemical signatures during OCV rest or discharge are associated with Li re-intercalation into graphite. Furthermore, this work provides insight into the Li–graphite interactions at the composite electrode level and can be used to inform strategies to diagnose and mitigate Li plating during fast charging.

25 ENERGY STORAGE↗
DOE OSTI2022

A mechanistic study of the dopant-induced breakdown in halide perovskites using solid state energy storage devices

Doping halide perovskites (HPs) with extrinsic species, such as alkali metal ions, plays a critical, albeit often elusive role in optimising optoelectronic devices. Here, we use solid state lithium ion battery inspired devices with a polyethylene oxide-based polymer electrolyte to dope HPs controllably with lithium ions. We perform a suite of operando material analysis techniques while dynamically varying Li doping concentrations. We determine and quantify three doping regimes; a safe regime, with doping concentrations of <10 20 cm –3 (2% Li : Pb mol%) in which the HP may be modified without detrimental effect to its structure; a minor decomposition regime, in which the HP is partially transformed but remains the dominant species; and a major decomposition regime in which the perovskite is superseded by new phases. We provide a mechanistic description of the processes mediating between each stage and find evidence for metallic Pb (0) , LiBr and LiPbBr 2 as final decomposition products. Combining results from synchrotron X-ray diffraction measurements with in situ photoluminescence and optical reflection microscopy studies, we distinguish the influences of free charge carriers and intercalated lithium independently. We find that the charge density is equally as important as the geometric considerations of the dopant species and thereby provide a quantitative framework upon which the future design of doped-perovskite energy devices should be based.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Local structure and ion storage properties of vanadate cathode materials regulated by the pre-alkalization

Aqueous Zn-ion batteries using mild acidic electrolytes utilizing a Zn 2+ /H + dual-ion storage mechanism have shown great potential in achieving high energy density comparable to non-aqueous lithium-ion batteries. Here, this study reveals that hydrated alkali-ions regulate the formation of alkali-intercalated vanadate layered compounds. Among various vanadate materials, lithium-intercalated vanadate has the largest interlayer spacing and most disordered local structure, exhibiting the largest storage capacity of 308 mA h g –1 at 0.05 A g –1 for Zn 2+ /H + dual-ion storage and improved charge transfer and transport kinetics and cycling performance, evidenced by in situ X-ray diffraction and ex situ X-ray total scattering and pair distribution function analysis. Our study provides new insight into designing layered vanadate materials for high-capacity aqueous batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

The Critical Stack Pressure to Alter Void Generation at Li/Solid-Electrolyte Interfaces during Stripping

The lithium stripping process generates vacancies, which may accumulate as voids and lead to uneven current distribution and dendrite growth in the following plating cycles. A stack pressure is typically required during stripping, but how to optimize the stack pressure is not clear. In this work, extremely lithiophilic Li/Li 2 O and lithiophobic Li/LiF interfaces were used to reveal the combining effect of interface interaction and stack pressure induced lithium creep on the stripping critical current density (CCD). A multiscale simulation scheme with Density Functional Theory (DFT), kinetic Monte Carlo (KMC) simulations, and an analytical model was developed. The analytical model predicted lithiophobic interfaces require a higher stack pressure than lithiophilic interfaces to reach the same CCD. The KMC simulations also showed higher stack pressure is needed at lithiophobic interfaces to accelerate Li vacancy diffusion into the bulk and maintain a flat surface. This stack pressure needs to be high enough to alter the Li forward-and-backward hopping barriers at the interface. This multiscale simulation scheme illustrates the importance to include the chemical-mechanical effects during Li stripping morphology evolution. It can be used to design ideal interlayer coating materials to maintain a flat Li surface during cycling.

25 ENERGY STORAGE↗
DOE OSTI2022

Progress and Prospects of Inorganic Solid-State Electrolyte-Based All-Solid-State Pouch Cells

Here, all-solid-state batteries have piqued global research interest because of their unprecedented safety and high energy density. Significant advances have been made in achieving high room-temperature ionic conductivity and good air stability of solid-state electrolytes (SSEs), mitigating the challenges at the electrode–electrolyte interface, and developing feasible manufacturing processes. Along with the advances in fundamental study, all-solid-state pouch cells using inorganic SSEs have been widely demonstrated, revealing their immense potential for industrialization. This review provides an overview of inorganic all-solid-state pouch cells, focusing on ultrathin SSE membranes, sheet-type thick solid-state electrodes, and bipolar stacking. Moreover, several critical parameters directly influencing the energy density of all-solid-state Li-ion and lithium–sulfur pouch cells are outlined. Finally, perspectives on all-solid-state pouch cells are provided and specific metrics to meet certain energy density targets are specified. This review looks to facilitate the development of inorganic all-solid-state pouch cells with high energy density and excellent safety.

25 ENERGY STORAGE↗
DOE OSTI2022

First lithium experiments in HIDRA and evidence of helium retention during quasi-steady-state stellarator plasma operations

Recent experiments in Hybrid Illinois Device for Research and Applications (HIDRA) have had operational discharges between t discharge = 60 and 1000 s using electron cyclotron resonant heating (ECRH) of the plasma. This means that quasi-steady-state plasma discharges reach conditions to study long-pulse plasma material interactions (PMIs). The newly commissioned HIDRA-Material Analysis Test-stand PMI diagnostic is used to place a drop of lithium onto a heated tungsten surface, transfer the sample in-vacuo and expose it in a helium plasma. Helium is of interest as there is an open question to whether lithium will be able to remove helium ash in real fusion devices. The introduction of the W-Li sample in HIDRA resulted in evaporation of lithium into the helium plasma during a 600 s pulse and caused a reduction of over 90% in neutral pressure during the discharge. It was also observed that the plasma density and temperature increased by over 2.5 times. Using spectroscopy and a helium collisional radiative model, the peak temperature and density of the helium plasma can be monitored during the discharge. During lithium evaporation, as significant lithium ionization occurs, there is a 85% drop in the HIDRA vessel neutral pressure, despite a constant flow rate of He gas. This reduction in neutral pressure is supported by spectroscopy data with corresponding reductions in He I line intensities (587 nm, 667 nm, 706 nm, and 728 nm), as well as those of other impurities. At one point in the discharge a lithium plasma is created, as indicated by an increase in Li + emission and a complete reduction in He + emission, but the electron density jumps from ne = 3 × 10 18 m –3 to over ne = 8 × 10 18 m –3 while the core temperature stays relatively constant between Te = 16 eV and 20 eV. Once lithium has completely evaporated from the sample and the majority of the ionized lithium has diffused from the plasma to the vessel walls, pressure and spectroscopy data paired with He collisional radiative model calculations shows a re-establishment of a helium plasma in a low recycling regime. In this regime, the density drops down to ne = 2 × 10 18 m –3 and the electron temperature increases from T e = 20 eV to over T e = 50 eV indicating an increase in helium heating efficiency. This is also indicated by the He+ emission re-establishing and having a higher intensity. Here, we show the results from the first lithium campaign in HIDRA. In the presence of lithium, and in particular when lithium ions are present, the helium disappears from the plasma via an as of yet unknown complex relationship that needs to be further studied. The most likely explanation is that the lithium ions are distributed around the vessel and able to trap helium to the surface turning HIDRA into a large gettering surface. These results have potential implications on future plasma facing component design using liquid lithium for impurity and recycling control using limiters and divertors.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

A High-Rate Aqueous Proton Battery Delivering Power Below -78 °C via an Unfrozen Phosphoric Acid

Lithium-sulfur batteries are attractive for automobile and grid applications due to their high theoretical energy density and the abundance of sulfur. Despite the significant progress in cathode development, lithium metal degradation and the polysulfide shuttle remain two critical challenges in the practical application of Li-S batteries. Development of advanced electrolytes has become a promising strategy to simultaneously suppress lithium dendrite formation and prevent polysulfide dissolution. Here, a new class of concentrated siloxane-based electrolytes, demonstrating significantly improved performance over the widely investigated ether-based electrolytes are reported in terms of stabilizing the sulfur cathode and Li metal anode as well as minimizing flammability. Through a combination of experimental and computational investigation, it is found that siloxane solvents can effectively regulate a hidden solvation-ion-exchange process in the concentrated electrolytes that results from the interactions between cations/anions and solvents. As a result, it could invoke a quasi-solid-solid lithiation and enable reversible Li plating/stripping and robust solid-electrolyte interphase chemistries. The solvation-ion-exchange process in the concentrated electrolytes is a key factor in understanding and designing electrolytes for other high-energy lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Molten Lithium-Brass/Zinc Chloride System as High-Performance and Low-Cost Battery

Batteries with high safety, low cost, and reasonable energy density are essential for grid-scale energy storage and still remain elusive. In this paper, we report a solid electrolyte-based liquid lithium-brass/zinc chloride (SELL-brass/ZnCl 2 ) battery using garnet-type lithium-ion solid electrolyte, lithium anode, and brass/ZnCl 2 cathode. The chemistry of the cell reaction and the ability of being assembled in discharged state ensures a high safety. The use of low-cost ZnCl 2 cathode can realize a low cell material cost of $16 kWh –1 . The adoption of lithium anode guarantees a high theoretical energy density of 750 Wh kg –1 and 2,250 Wh L –1 . Moreover, by using brass powder as a Zn source in the cathode, the Zn particle growth issue is successfully solved, and a good cycling stability of the battery can be obtained. As full cell performance and scalability are also verified, our SELL-brass/ZnCl 2 battery shows a high potential for practical use in grid energy storage.

25 ENERGY STORAGE↗
DOE OSTI2022

Conformal LiF Stabilized Interfaces via Electrochemical Fluorination on High Voltage Spinel Cathodes (≈4.9 V) for Lithium-Ion Batteries

The high voltage LiNi 0.5 Mn 1.5 O 4 (LNMO) spinel is one of the promising cathodes for the lithium-ion batteries due to its high energy densities, good rate performance. However, its high operating potential (≈4.75 V) causes extensive oxidation of conventional carbonate electrolytes, resulting an unstable and thick cathode electrolyte interphase (CEI) layer with a large irreversible capacity and low coulombic efficiency. In this work, we report the formation of thin LiF stabilized interfaces on LNMO via electrochemical fluorination that significantly improves the cycling stability and enhanced the capacity. An electrochemically induced conformal LiF layer acts as a part of a robust CEI by reducing the leakage of electrons and allowing the conduction of Li ions through it. Because of the robust LiF stabilized CEI, LNMO delivers a discharge capacity of ≈148.5 and ≈117.1 mAh g -1 at 0.1 and 1 C rate, respectively. It exhibits excellent cyclability with 80% capacity retention (CR) after 600 cycles in lithium-half cell and ≈90% CR after 200 cycles in full cell with only 0.03% and 0.05% capacity decay per cycle in conventional carbonate electrolytes without additives. Such an excellent electrochemical performance could lead to the potential development of high energy density batteries with high voltage cathodes for grid-based applications.

25 ENERGY STORAGE↗