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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 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Revisiting the Impact of Anion Selection on Sulfur Redox Reaction Kinetics for High Sulfur Loading Lithium–Sulfur Batteries

Lithium bis(trifluoromethane)sulfonimide (LiTFSI) is widely used in lithium–sulfur (Li–S) battery electrolytes due to its stability with lithium polysulfides (LiPSs) and moderate compatibility with lithium metal anodes. However, LiTFSI presents environmental concerns due to its association with per- and polyfluoroalkyl substances (PFAS), which are environmentally persistent and potentially toxic, raises sustainability concerns. This research also reveals that LiTFSI limits sulfur redox reactions (SRRs), making it less effective than other lithium salts. Additionally, some salts previously considered incompatible with Li-S systems due to their reactivity with LiPSs are demonstrated to perform effectively. For the first time, a protective, porous cathode electrolyte interphase (CEI) formed in situ through reactions between salt anions and LiPS is reported. The cells delivered a high specific capacity of 1230.8 mAh g −1 at 0.05 C with a sulfur loading of ≈6 mg cm −2 , limited lithium anode, maintaining a capacity retention of 76.2% after 100 cycles at 0.1 C. Under harsh conditions, such as high sulfur loading, lean electrolyte conditions (3 µL mg −1 ), and in anode-free cells, the cells continued to deliver outstanding capacity. This work provides valuable guidelines for understanding and selecting lithium salts to advance electrolyte design for Li–S batteries.

high loading batteries↗
DOE OSTI2022

Correlation between Redox Potential and Solvation Structure in Biphasic Electrolytes for Li Metal Batteries

The activity of lithium ions in electrolytes depends on their solvation structures. However, the understanding of changes in Li + activity is still elusive in terms of interactions between lithium ions and solvent molecules. Herein, the chelating effect of lithium ion by forming [Li(15C5)] + gives rise to a decrease in Li + activity, leading to the negative potential shift of Li metal anode. Moreover, weakly solvating lithium ions in ionic liquids, such as [Li(TFSI) 2 ] - (TFSI = bis(trifluoromethanesulfonyl)imide), increase in Li + activity, resulting in the positive potential shift of LiFePO 4 cathode. This allows the development of innovative high energy density Li metal batteries, such as 3.8 V class Li | LiFePO 4 cells, along with introducing stable biphasic electrolytes. In addition, correlation between Li + activity, cell potential shift, and Li + solvation structure is investigated by comparing solvated Li + ions with carbonate solvents, chelated Li + ions with cyclic and linear ethers, and weakly solvating Li + ions in ionic liquids. These findings elucidate a broader understanding of the complex origin of Li + activity and provide an opportunity to achieve high energy density lithium metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2024

Recent Progress on Dominant Sulfide‐Type Solid‐State Na Superionic Conductors for Solid‐State Sodium Batteries

Abstract Over the past decade, solid‐state batteries have garnered significant attentions due to their potentials to deliver high energy density and excellent safety. Considering the abundant sodium (Na) resources in contrast to lithium (Li), the development of sodium‐based batteries has become increasingly appealing. Sulfide‐based superionic conductors are widely considered as promising solid eletcrolytes (SEs) in solid‐state Na batteries due to the features of high ionic conductivity and cold‐press densification. In recent years, tremendous efforts have been made to investigate sulfide‐based Na‐ion conductors on their synthesis, compositions, conductivity, and the feasibility in batteries. However, there are still several challenges to overcome for their practical applications in high performance solid‐state Na batteries. This article provides a comprehensive update on the synthesis, structure, and properties of three dominant sulfide‐based Na‐ion conductors (Na 3 PS 4 , Na 3 SbS 4 , and Na 11 Sn 2 PS 12 ), and their families that have a variety of anion and cation doping. Additionally, the interface stability of these sulfide electrolytes toward the anode is reviewed, as well as the electrochemical performance of solid‐state Na batteries based on different types of cathode materials (metal sulfides, oxides, and organics). Finally, the perspective and outlook for the development and practical utilization of sulfide‐based SE in solid‐state batteries are discussed.

Guo, Xiaolin↗
DOE OSTI2020

An epoxy-reinforced ceramic sheet as a durable solid electrolyte for solid state Na-ion batteries

In a conventional Na-ion battery system using liquid electrolyte, there are critical safety issues due to the instability of the liquid electrolyte. Na 3 Zr 2 Si 2 PO 12 (NASICON) solid electrolyte is a material that is sufficient to replace a liquid electrolyte as it has high ionic conductivity and thermal and electrochemical stability. However, as there is a large interfacial resistance in the NASICON solid electrolyte powder, even when used in combination with a polymer electrolyte, the advantageous effects of ceramics are not easily exhibited. In this study, we propose a top-down method of combining a polymer with a ceramic in which an ion transport channel is previously formed. In this method, a NASICON solid electrolyte is partially sintered to form ion transport channels. Then the NASICON solid electrolyte pores are filled with an epoxy polymer to increase the strength of the epoxy-NASICON composite electrolyte. This method demonstrates the possibility of our composite electrolyte being used as a thin and strong film. As a result of our methods, the ionic conductivity and thermal and electrochemical stability of NASICON were maintained, while the physical strength was enhanced by approximately 2 times. In addition, a capacity of 120 mA h g -1 and stability of 20 cycles were confirmed in a half cell with a Na 3 V 2 (PO 4 ) 3 cathode and Na metal. This method proposes a new direction for research regarding composite electrolytes created using an oxide-based solid electrolyte.

25 ENERGY STORAGE↗
DOE OSTI2025

Upcycling Polyethylene Waste into Hybrid Graphitic Porous Carbon Materials Used in High‐Performance Zinc‐Ion Hybrid Capacitors

Polyethylene (PE) waste is a challenge to upcycle into useful materials because this plastic tends to decompose into volatile compounds when heated at relatively low temperatures. In this work, mixtures of PE wastes into a hybrid graphitic porous carbon (HGPC) by a thermal oxidation pretreatment step, with assistance of an inert solid additive (KCl), to functionalize, crosslink, and stabilize the PE waste followed by carbonization and catalytic graphitization steps with a potassium carbonate catalyst, are upcycled. The PE waste‐derived HGPC (PW‐HGPC) has a hybrid structure composed of graphene‐like carbon nanosheets grown on the surface of carbon particles, high porosity with specific surface area, up to 1,763 m 2 g −1 , and good graphitic degree with average Raman I 2D / I G ratios of 0.53. When used as cathode material for zinc‐ion hybrid capacitors, this PW‐HGPC exhibits an excellent specific capacity, up to 126.7 mAh g −1 , at high mass loading of 10 mg cm −2 . Moreover, PW‐HGPC exhibits remarkable cycling stability with capacity retention of >94% after 10 000 cycles. Additionally, the KCl is recycled and reused over five times. This method provides a new solution for upcycling PE wastes into high value‐added carbon materials, not only for zinc‐ion hybrid capacitors but also for other electrochemical energy storage device applications.

hybrid graphitic porous carbon↗
DOE OSTI2026

Lattice-Oxygen-Driven Selective Oxidation Strategy for Stable Argyrodite Solid-State Lithium Metal Batteries

All-solid-state lithium metal batteries (ASSLMBs) with Li6PS5Cl argyrodite electrolytes and high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes offer high energy density but suffer from rapid capacity fading due to the layered-to-rock-salt transition of NMC811 and structural degradation of Li6PS5Cl from parasitic interfacial reactions. Here, we demonstrate a catholyte engineering strategy using a Li2S scavenging additive to suppress interfacial reactivity and preserve the structural and electrochemical stability of both NMC811 and Li6PS5Cl. Incorporating 0.10 wt.% Li2S enables exceptional cycling stability, achieving 76% capacity retention after 550 cycles at C/10 and 88% retention after 800 cycles at C/3 at 60 degrees C, compared with rapid failure in pristine cells. Spectroscopic, electrochemical, and morphological analyses confirm that Li2S maintains electrode integrity by sustaining particle contact and suppressing phase decomposition. This work elucidates interfacial degradation pathways in NMC811/argyrodite systems and introduces a low-cost, scalable strategy to stabilize nickel-rich oxide cathodes in ASSLMBs, advancing their practical viability.

25 ENERGY STORAGE↗
DOE OSTI2020

Complementary Effects of Mg and Cu Incorporation in Stabilizing the Cobalt-Free LiNiO 2 Cathode for Lithium-Ion Batteries

Since the discovery of LiNiO 2 several decades ago, a new era of electric vehicles demanding high-energy-density lithium-ion batteries (LIBs) has recently rebooted the interest in this cathode material to eliminate the dependence on expensive and scarcely available cobalt. However, LiNiO 2 has been plagued by cycle instability, thermal instability, and air instability. We present here an exploration of the mutual interaction of magnesium and copper in stabilizing the cobalt-free LiNiO 2 cathode. Although Mg doping is beneficial for the robustness of the bulk structure of LiNiO 2 , surface characterization results of Mg-doped LiNiO 2 implies the need for further surface protection. To that end, we have incorporated Cu in addition to Mg in that Cu stabilizes the surface of Mg-doped LiNiO 2 by forming a protective stable surface layer without harming the bulk. Notable variations of the surface residual lithium composition (Li Li 2 CO 3 /Li LiOH ) along with the incorporation of stabilizers are also discussed. The harmony between Mg and Cu with as little as 0.5 atom % Mg and 0.3 atom % Cu significantly enhances the specific energy and cycle life of LiNiO 2 . Furthermore, this study demonstrates how the co-incorporation of optimal dopants can help stabilize both the bulk and surface and provides new insights toward developing cobalt-free layered oxide cathodes for high-energy-density LIBs.

25 ENERGY STORAGE↗
DOE OSTI2020

High-Capacity P2-Type Na x Li 0.25 Mn 0.75 O 2 Cathode Enabled by Anionic Oxygen Redox

Sodium-ion battery technology has attracted significant attention due to its substantial cost advantage and similar operating mechanism to Li-ion batteries. P2-type sodium manganese oxide cathode is one of the most promising candidates, demonstrating both high capacity and good cycling stability. Here, we explore the lattice oxygen activity in layered sodium transition metal oxides. We synthesize a series of sodium lithium manganese oxides, NaxLi 0.25 Mn 0.75 O2 (x = 0.75 – 0.833), to optimize Na content. We further investigate the charge compensation mechanism for the best performing Na 0.75 Li 0.25 Mn 0.75 O 2 over an extensive electrochemical cycling window. The large charge and discharge capacity is enabled by reversible lattice oxygen redox in the high voltage region (≥2.5 V), along with Mn redox at the voltages below 2.5 V. Additionally, we reveal a small amount of oxygen gas evolution, 0.04% of the total oxygen in Na 0.25 Li 0.25 Mn 0.75 O 2 . This initial study will trigger an interest in the lattice oxygen activity in layered sodium metal oxide cathode, therefore, leading to better understanding of its correlation with crystal structure and electrochemical performance.

25 ENERGY STORAGE↗
DOE OSTI2021

Electrolytes Polymerization‐Induced Cathode‐Electrolyte‐Interphase for High Voltage Lithium‐Ion Batteries

Abstract Lithium‐ion batteries (LIBs) based on LiNi x Co y Mn 1‐x‐y O 2 (NCM) cathode materials have been widely commercialized, because of their high energy density, favorable rate performance, and relatively low cost. However, with increased Ni content to further increase their energy density, their cycling stability deteriorates dramatically and thus fails to meet the commercial application requirements. The artificial cathode‐electrolyte‐interphase (CEI) is a promising approach to solve this problem. Here, a robust CEI is fabricated through in situ polymerization of ethylene carbonate induced by aluminum isopropoxide (AIP). By adding 1 wt.% AIP in a commercial electrolyte, the capacity retention of LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cell at 1 C rate has been significantly increased from 80.8% to 97.8% with a highly reversible capacity of 176 mA h g −1 after 200 cycles. AIP can be also used as an additive during the slurry‐making process, enabling a reversible capacity of 170 mA h g −1 for LiCoO 2 after 200 cycles even at a high charge cut‐off voltage of 4.6 V. It is confirmed that the in situ formed CEI layer can prevent the cathodes from cracking and reduce the irreversible phase transformation.

Yang, Jixiang↗
DOE OSTI2020

Lithium-Sulfur Batteries with a Block Copolymer Electrolyte Analyzed by X-ray Microtomography

Most of the work on Lithium-sulfur (LiS) batteries use liquid electrolytes that have limited stability when coupled with Li metal anodes. We have studied LiS batteries with a solid block copolymer electrolyte which exhibits improved stability against Li anodes. Additionally, the electrolyte comprises a polystyrene-b-poly(ethylene oxide) (SEO) copolymer doped with a Li salt. Hollow carbon nanospheres impregnated with sulfur were used to build a composite cathode. Two types of sulfur-impregnated functionalized carbon nanospheres were used: One with carboxylic acid groups and the other with short lithium poly(4-styrenesulfonyl(trifluoromethylsulfonyl)imide) (PSTFSI-Li) chains. Cells with Li S dissolved in the SEO based electrolyte served as the baseline. After cycling, the reason for capacity fade was determined by imaging the batteries using synchrotron hard X-ray microtomography. It is generally assumed that LiS cells fail due to dissolution of polysulfide into the liquid electrolyte, i.e., the main problems related to the cathode. In our all-solid cells, failure was primarily due to delamination of the Li foil from the polymer electrolyte layer. Delamination is also observed at the sulfur cathode. It is likely that the large changes in volume of the active materials during cycling induce delamination in all-solid LiS cells. 2 8

25 ENERGY STORAGE↗
DOE OSTI2022

Design, Processing, and Integration of Pouch-Format Cell for High-Energy Lithium-Sulfur Batteries

This project objective was to develop and demonstrate a lithium-sulfur (Li-S) battery in a pouch-format cell capable of achieving an energy density ≥ 500 Wh/kg while achieving a 1,000 cycle life. The research focused on cell optimization and fabrication addressing different technical barriers and challenges including: 1) thin lithium anode optimization; 2) current collector and tab attachment design; 3) cathode porosity control; 4) electrolyte to sulfur ratio control; 5) cell design; and 6) cell fabrication. The project developed and demonstrated various technologies to address these technical barriers and challenges. The project demonstrated a thin lithium anode by vapor deposition, a collector design and validation of laser welding of tab attachment method, a cathode porosity control strategy by binder optimization, a calendaring process control and surface/interface treatment, and an electrolyte to sulfur ratio control with influence on cell energy density. The sulfur cathode was optimized by tuning the formulation, optimizing the calendaring process, and introducing a novel electrode fabrication process. To address the electrolyte performance issue, the electrolyte optimization was achieved with additive and formulation tuning and the introduction of a dual-phase electrolyte system. In addition to the demonstration of the optimized electrode with a novel fast-curing coating process and dual-phase electrolyte, a coating separator was further developed to address the polysulfide shuttling issue. The resulting new cell design with these optimized cell components was demonstrated in the 1 Ah pouch cell with medium sulfur loading and moderate porosity (~ 4.5 mAh cm-2, 65% porosity) and showed an energy density of > 400 Wh/kg (with E/S ratio of 2.8). The Li-SPAN cell configuration was also evaluated in combination with a new dual-phase electrolyte system. Initial coin cell performance demonstrated cycle stability of >300 cycles with an estimated energy density of 300 Wh/kg at the pouch format level. The corresponding 1 Ah pouch format SPAN cells with the new polymer electrolyte were developed which has shown a stable capacity at 800-900 mAh for ~40 cycles so far.

25 ENERGY STORAGE↗
DOE OSTI2021

Lithium metal—seawater battery cells having protected lithium electrodes

Active metal and active metal intercalation electrode structures and battery cells having ionically conductive protective architecture including an active metal (e.g., lithium) conductive impervious layer separated from the electrode (anode) by a porous separator impregnated with a non-aqueous electrolyte (anolyte). This protective architecture prevents the active metal from deleterious reaction with the environment on the other (cathode) side of the impervious layer, which may include aqueous or non-aqueous liquid electrolytes (catholytes) and/or a variety electrochemically active materials, including liquid, solid and gaseous oxidizers. Safety additives and designs that facilitate manufacture are also provided.

Visco, Steven J.↗
DOE OSTI2023

Making lithium metal—seawater battery cells having protected lithium electrodes

Active metal and active metal intercalation electrode structures and battery cells having ionically conductive protective architecture including an active metal (e.g., lithium) conductive impervious layer separated from the electrode (anode) by a porous separator impregnated with a non-aqueous electrolyte (anolyte). This protective architecture prevents the active metal from deleterious reaction with the environment on the other (cathode) side of the impervious layer, which may include aqueous or non-aqueous liquid electrolytes (catholytes) and/or a variety electrochemically active materials, including liquid, solid and gaseous oxidizers. Safety additives and designs that facilitate manufacture are also provided.

Visco, Steven J.↗
DOE OSTI2020

The Role of Secondary Particle Structures in Surface Phase Transitions of Ni-Rich Cathodes

Nanometer-thick reconstruction layers on layered cathode surfaces have been widely observed on both pristine and cycled materials. However, the mechanisms of reconstruction and the role that these structures play in electrochemical performance are not fully understood. From a crystallographic perspective, such surface reconstruction layers result from cation site-mixing between Li and transition-metal ions, but it remains far from clear as to what the critical factors are that control such cation mixing for various cathode chemistries. In this paper, we report observations on surface transformations during cycling of a Ni-rich cathode-oxide that are governed by direct contact with the liquid electrolyte. Specifically, within a secondary particle, the three-dimensional hierarchical aggregate of primary particles leads to the formation of grain boundaries of different characteristics, including open grain boundaries that allow the permeation of liquid electrolyte, and closed grain boundaries that exclude liquid electrolyte penetration. Upon battery cycling, surfaces in direct contact with the liquid electrolyte showed a surface reconstruction layer while the surfaces that did not have contact with the electrolyte showed no such reconstructions. In addition, the critical role of oxygen in reconstruction of grain boundaries is demonstrated, and the unexpected oxygen depletion at twin boundaries result in severe phase transitions. The present work provides further insights into phase transitions at solid-solid and solid-liquid interfaces within secondary cathode particles and suggests strategies for mitigating surface/interfacial degradation.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Enabling Facile Anionic Kinetics through Cationic Redox Mediator in Li-Rich Layered Cathodes

Anionic oxygen redox has aroused great interests in developing high-capacity Li-ion battery cathode materials. The fundamental understanding of this concept, compared to cationic redox, has promoted extensive studies on lithium transition metal oxides including those of 4d and 5d transition metals. Lithium ruthenium oxide has been found to exhibit a reversible anionic redox upon cycling. However, lithium-rich layered oxide with anionic redox is still facing great challenges such as sluggish kinetics. Here we investigate the effect of cationic redox on the kinetics of anionic reaction when they are strongly coupled. We report the cobalt substituted lithium ruthenium oxide, where all Ru, Co and O redox participate in the charge compensation mechanism in relatively defined voltage regions. Additionally, the improved anionic kinetics is attributed to the fast cationic Co redox process that serves as a redox mediator. Our work sheds light into the potential direction to address the commonly believed sluggish anionic kinetics in high-capacity oxygen-redox cathode materials.

25 ENERGY STORAGE↗
DOE OSTI2025

An unwanted guest in the electrochemical oxidation of high-voltage Li-ion battery electrolytes: the life of highly reactive protons

Lithium-ion batteries (LIBs) are central to the urgent societal need to decarbonize both transportation and energy storage on the grid. Unfortunately, despite their attractive energy/power density, as well as high coulombic and energy efficiencies, further improvement of this technology – especially their durability – is desperately needed. To support these efforts, our study focuses on fundamental understanding of the decomposition pathways for LIB electrolytes at the cathode–electrolyte interface (CEI), as the nature of these reactions directly controls the extent to which cell capacity and voltage decays in these systems. In this study, we employ electrochemical methods, coupled with product analysis using NMR spectroscopy and mass spectrometry, to determine the decomposition mechanisms in both model and technologically relevant electrolytes. Remarkably, we discovered the electrochemical formation of protons with high chemical activity, comparable to known superacids, at potentials relevant to practical Li-ion batteries. Their reactivity toward every individual component of the CEI provides a unified thermochemical origin for a myriad of side reactions that are commonly associated with the electrochemical reaction. In particular, electrochemically generated protons react with intact EC molecules to form CO 2 and other short and long chain ethers. They also undergo an acid–base reaction with LiPF 6 , to form the weaker acid HF, and with the cathode active material, leaching transition metals into the electrolyte. Collectively, the results of this study all point to the urgent need to either mitigate this proton formation or introduce benign harvesting additives via new electrolyte design strategies.

Ilic, Stefan [Argonne National Laboratory (ANL), A↗
DOE OSTI2024

Wavelength modulation laser-induced fluorescence for plasma characterization

Laser-Induced Fluorescence (LIF) spectroscopy is an essential tool for probing ion and atom velocity distribution functions (VDFs) in complex plasmas. VDFs carry information about the kinetic properties of species that is critical for plasma characterization. Accurate interpretation of these functions is challenging due to factors such as multicomponent distributions, broadening effects, and background emissions. Our research investigates the use of Wavelength Modulation (WM) LIF to enhance the sensitivity of VDF measurements. Unlike standard Amplitude Modulation (AM) methods, WM–LIF measures the derivative of the LIF signal. This approach makes variations in VDF shape more pronounced. VDF measurements with WM–LIF were investigated with both numerical modeling and experimental measurements. The developed model enables the generation of both WM and AM signals, facilitating comparative analysis of fitting outcomes. Experiments were conducted in a weakly collisional argon plasma with magnetized electrons and non-magnetized ions. Measurements of the argon ion VDFs employed a narrow-band tunable diode laser, which scanned the 4p 4 D 7/2 –3d 4 F 9/2 transition centered at 664.553 nm in vacuum. A lock-in amplifier detected the second harmonic WM signal, which was generated by modulating the laser wavelength with an externally controlled piezo-driven mirror of the diode laser. Finally, our findings indicate that the WM–LIF signal is more sensitive to fitting parameters, allowing for better identification of VDF parameters such as the number of distribution components, their temperatures, and velocities. In addition, WM–LIF can serve as an independent method to verify AM measurements and is particularly beneficial in environments with substantial light noise or background emissions, such as those involving thermionic cathodes and reflective surfaces.

47 OTHER INSTRUMENTATION↗