Search NASA⌕ Search

SEARCH · Search NASA

Results for “Li metal”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Tension‐Induced Cavitation in Li‐Metal Stripping

Abstract Designing stable Li metal and supporting solid structures (SSS) is of fundamental importance in rechargeable Li‐metal batteries. Yet, the stripping kinetics of Li metal and its mechanical effect on the supporting solids (including solid electrolyte interface) remain mysterious to date. Here, through nanoscale in situ observations of a solid‐state Li‐metal battery in an electron microscope, two distinct cavitation‐mediated Li stripping modes controlled by the ratio of the SSS thickness ( t ) to the Li deposit's radius ( r ) are discovered. A quantitative criterion is established to understand the damage tolerance of SSS on the Li‐metal stripping pathways. For mechanically unstable SSS ( t / r < 0.21), the stripping proceeds via tension‐induced multisite cavitation accompanied by severe SSS buckling and necking, ultimately leading to Li “trapping” or “dead Li” formation; for mechanically stable SSS ( t / r > 0.21), the Li metal undergoes nearly planar stripping from the root via single cavitation, showing negligible buckling. This work proves the existence of an electronically conductive precursor film coated on the interior of solid electrolytes that however can be mechanically damaged, and it is of potential importance to the design of delicate Li‐metal supporting structures to high‐performance solid‐state Li‐metal batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A polymeric composite protective layer for stable Li metal anodes

Lithium (Li) metal is a promising anode for high-performance secondary lithium batteries with high energy density due to its highest theoretical specific capacity and lowest electrochemical potential among anode materials. However, the dendritic growth and detrimental reactions with electrolyte during Li plating raise safety concerns and lead to premature failure. Herein, we report that a homogeneous nanocomposite protective layer, prepared by uniformly dispersing AlPO 4 nanoparticles into the vinylidene fluoride-co-hexafluoropropylene matrix, can effectively prevent dendrite growth and lead to superior cycling performance due to synergistic influence of homogeneous Li plating and electronic insulation of polymeric layer. The results reveal that the protected Li anode is able to sustain repeated Li plating/stripping for >750 cycles under a high current density of 3 mA cm -2 and under a practical specific capacity of 2 mAh cm -2 . Moreover, full-cell Li-ion battery is constructed by using LiFePO 4 and protected Li as a cathode and anode, respectively, rendering a stable capacity after 400 charge/discharge cycles. The current work presents a promising approach to stabilize Li metal anodes for next-generation Li secondary batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

Controlled Experiments and Optimized Theory of Absorption Spectra of Li Metal and Salts

Investigation of Li metal and ionic compounds through experimental and theoretical spectroscopy has been of tremendous interest due to their prospective applications in Li-metal and Li-ion batteries. Li K-edge soft X-ray absorption spectroscopy (sXAS) provides the most direct spectroscopic characterization; unfortunately, due to the low core-level energy and the highly reactive surface, Li-K sXAS of Li metal has been extremely challenging, as evidenced by many controversial reports. Here, through controlled and ultra-high energy resolution experiments of two kinds of in situ prepared samples, we report the intrinsic Li-K sXAS of Li-metal that displays a prominent leading peak that has not been revealed before. Furthermore, theoretical simulations show that, due to the low number of valence electrons in Li, the Li-K sXAS is strongly affected by the response of the valence electrons to the core hole. We successfully reproduce the Li-K sXAS by state-of-the-art calculations with considerations of a number of relevant parameters such as temperature, energy resolution, and, especially, contributions from transitions which are forbidden in the single-particle treatment. Such a comparative experimental and theoretical investigation is further extended to a series of Li ionic compounds, which highlight the importance of considering the total and single-particle energies for obtaining an accurate alignment of the spectra. Furthermore, our work provides the first reliable Li-K sXAS of the Li metal surface with advanced theoretical calculations. The experimental and theoretical results provide a critical benchmark for studying Li chemistry in both metallic and ionic states.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Ionic conductive polymers as artificial solid electrolyte interphase films in Li metal batteries – A review

Lithium (Li) metal has been considered as the ultimate anode material for next-generation rechargeable batteries due to its ultra-high theoretical specific capacity (3860 mAh g -1 ) and the lowest reduction voltage (-3.04 V vs the standard hydrogen electrode). However, the dendritic Li formation, uncontrolled interfacial reactions, and huge volume variations lead to unstable solid electrolyte interphase (SEI) layer, low Coulombic efficiency and hence short cycling lifetime. Designing artificial solid electrolyte interphase (artificial SEI) films on the Li metal electrode exhibits great potential to solve the aforementioned problems and enable Li–metal batteries with prolonged lifetime. Polymer materials with good ionic conductivity, superior processability and high flexibility are considered as ideal artificial SEI film materials. In this review, according to the ionic conductive groups, recent advances in polymeric artificial SEI films are summarized to afford a deep understanding of Li ion plating/stripping behavior and present design principles of high-performance artificial SEI films in achieving stable Li metal electrodes. Perspectives regarding to the future research directions of polymeric artificial SEI films for Li–metal electrode are also discussed. The insights and design principles of polymeric artificial SEI films gained in the current review will be definitely useful in achieving the Li–metal batteries with improved energy density, high safety and long cycling lifetime toward next-generation energy storage devices.

25 ENERGY STORAGE↗
DOE OSTI2024

Nanoporous Carbon Coatings Direct Li Electrodeposition Morphology and Performance in Li Metal Anode Batteries

Li metal anodes could significantly improve battery energy density. However, Li generally electrodeposits in poorly controlled morphology, leading to safety and performance problems. One factor that controls Li anode performance and electrodeposition morphology is the nature of the electrolyte–current collector interface. Herein, we modify the Cu current collector interface by depositing precisely controlled nanoporous carbon (NPC) coatings using pulsed laser deposition to develop an understanding of how NPC coating density and thickness impact Li electrodeposition. We find that NPC density and thickness guide Li morphological evolution differently and dictate whether Li deposits at the NPC-Cu or NPC-electrolyte interface. NPC coatings generally lower overpotential for Li electrodeposition, though thicker NPC coatings limit kinetics when cycling at a high rate. Lower-density NPC enables the highest Coulombic efficiency (CE) during calendar aging tests, and higher-density NPC enables the highest CE during cycling tests.

25 ENERGY STORAGE↗
DOE OSTI2022

Consolidation of composite cathodes with NCM and sulfide solid-state electrolytes by hot pressing for all-solid-state Li metal batteries

In this study, hot pressing was evaluated as a method of cell fabrication to increase the energy density of next-generation all-solid-state batteries with NCM active material and sulfide solid-state electrolyte. Hot pressing involves consolidating glassy sulfide electrolyte by the application of pressure at a temperature above the electrolyte’s glass transition temperature. Typically, cell stacks are formed at room temperature and retain 15–30% porosity that limits cell energy density. On the other hand, the porosity of hot-pressed cell stacks is reduced to less than 10%. The electrochemical function of hot-pressed cathode composites was assessed as a function of active material and solid-state electrolyte compositions. Specifically, LiNi 0.85 Co 0.10 Mn 0.05 O 2 and LiNi 0.6 Co 0.2 Mn 0.2 O 2 were studied in combination with either glassy Li 7 P 3 S 11 , glassy Li 3 PS 4 , or β-Li 3 PS 4 solid-state electrolytes. Cathode composites composed of LiNi 0.6 Co 0.2 Mn 0.2 O 2 and Li 3 PS 4 maintained the best function after hot pressing at 200 °C and 370 MPa for 10 min. It was found that LiNi 0.6 Co 0.2 Mn 0.2 O 2 ’s resistance to microcracking and the inherent stability of Li 3 PS 4 ’s fully de-networked local structure are critical to maintain good electrochemical function after hot pressing. Furthermore, the results of this study show that hot pressing reduces porosity in the cathode composite and confirms the feasibility of cathode support of consolidated, reinforced glass separators.

25 ENERGY STORAGE↗
DOE OSTI2023

Superior metal storage behavior of Zn-containing porous carbon nanostructures for Na and Li metal batteries

Na and Li metals are ideal anodes for high-energy rechargeable batteries. However, their poor coulombic efficiency and the associated safety issues due to dendritic metal deposition and large volume changes during metallic plating/stripping are the major causes that persistently hinder their practical energy-storage applications. Herein, Zn-containing carbon nanostructures derived from typical zeolitic imidazolate framework-8 (ZIF-8) are proposed as advanced metal anode materials for both Na and Li metal batteries. In this study; the three-dimensional interconnected porous surfaces confine metallic Na and Li within the nanostructures, filling the carbon scaffold, and covering the electrode surface to form stable solid electrolyte interphases. Based on the metal nucleation and growth results obtained through various electrochemical tests, Zn incorporation and pore morphology have been revealed to be the key factors that regulate the metal nucleation and metallic plating/stripping during cycling. Thus, the incorporation of Zn in the closed pores of a carbon nanostructure improves the cycle performance, even in carbonate electrolytes, and produces stable Na and Li metallic anodes for next-generation rechargeable batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Modeling Electrodeposition in 3D Porous Architectures for Solid-State Li-Metal Batteries

Li-metal storage in three-dimensional (3D) electrodes is considered a potential dendrite-mitigation strategy. The large surface area and high porosity of these electrodes result in reduced local Li-plating current densities. The porous topology provides a scaffold for Li-deposition and stripping, maintaining both mechanical integrity and Li accessibility. The goal of this study is to understand how characteristics, such as geometry and material properties, affect the current distribution and deposition pattern. To this end, we developed a computational method to track material growth driven by electrodeposition within a complex geometry. This method ensures that the finite-element discretization remains conforming to the moving boundary while preserving an adequate mesh quality, and thus maintains solution accuracy. Using this new computational tool, we analyze the conditions under which porous anode architectures effectively expand the surface area of the charge-transfer interface, and self-regulate current density and dendrite growth.

3D electrode architectures↗
DOE OSTI2021

The effect of aspect ratio on the mechanical behavior of Li metal in solid-state cells

The Li metal anode is necessary for solid-state batteries to dramatically exceed the energy density of state-of-the-art conventional Li-ion batteries. To enable the Li metal anode, the mechanical properties of Li metal under compression in a commercially relevant cell configuration must be determined. This work examines the compression creep behavior of Li metal coupled with a relevant model solid-state electrolyte (Li 6.5 La 3 Ta 0.5 Zr 1.5 O 12 ) and current collector (Ni) as a function of applied stress (1–10 MPa) and Li foil thickness (100–700 μm). At 1 MPa applied stress, the strain rate of all Li foil thicknesses under compression was almost four orders of magnitude lower than what is predicted from tensile creep tests. Steady-state creep behavior was observed for Li foil ≥350 μm at 5 MPa and ≥250 μm at 10 MPa. Conversely, sustained creep deformation was not observed for 100 and 150 μm Li foils at any applied stress. It is suggested that friction at the Li/LLZO and Li/Ni interfaces leads to the formation of hydrostatic stress that controls Li deformation at low aspect ratios. Finally, these results have implications for battery pack stack pressure requirements, particularly relating to void formation during stripping and Li metal filament penetration during plating.

25 ENERGY STORAGE↗
DOE OSTI2022

Ultra-Stretchable, Ionic Conducting, Pressure-Sensitive Adhesive with Dual Role for Stable Li-Metal Batteries

The practical application of lithium (Li) metal battery is impeded by the Li dendrite growth and unstable solid electrolyte interphase (SEI) layer. Herein, an ultra-stretchable and ionic conducting chemically crosslinked pressure-sensitive adhesive (cPSA) synthesized via the copolymerization of 2-ethylhexyl acrylate and acrylic acid with poly(ethyleneglycol)dimethacrylate as crosslinker (short for 70cPSA), is developed as both artificial SEI layer and solid polymer electrolyte (SPE) for stable Li-metal electrode, enabling all-solid-state Li metal batteries with excellent cycling performance. As an artificial SEI layer, the 70cPSA-modified electrodes exhibit excellent electrochemical performance in Li|70cPSA@Cu half cells and 70cPSA@Li|70cPSA@Li symmetric cells. In full cells with LiFePO 4 (LFP) as cathode, the 70cPSA@Li|LFP cell exhibits stable cycling performance over 250 cycles. Utilized as SPE, the all-solid-state Li|SPE|LFP cell delivers excellent cycling stability with a capacity retention of 86% over 500 cycles. With high-voltage LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) as cathode, the Li|SPE|NMC811 cell exhibits a discharge capacity of 124.3 mAh g -1 with a capacity retention of 71% after 200 cycles. Furthermore, the rational design of PSAs and investigation of their dual role for stable and safe Li-metal batteries may shed a light on adhesive polymers for battery applications.

25 ENERGY STORAGE↗
DOE OSTI2024

Interfacial solvation-structure regulation for stable Li metal anode by a desolvation coating technique

Rechargeable lithium (Li) metal batteries face challenges in achieving stable cycling due to the instability of the solid electrolyte interphase (SEI). The Li-ion solvation structure and its desolvation process are crucial for the formation of a stable SEI on Li metal anodes and improving Li plating/stripping kinetics. This research introduces an interfacial desolvation coating technique to actively modulate the Li-ion solvation structure at the Li metal interface and regulate the participation of the electrolyte solvent in SEI formation. Through experimental investigations conducted using a carbonate electrolyte with limited compatibility to Li metal, the optimized desolvation coating layer, composed of 12-crown-4 ether-modified silica materials, selectively displaces strongly coordinating solvents while simultaneously enriching weakly coordinating fluorinated solvents at the Li metal/electrolyte interface. This selective desolvation and enrichment effect reduce solvent participation to SEI and thus facilitate the formation of a LiF-dominant SEI with greatly reduced organic species on the Li metal surface, as conclusively verified through various characterization techniques including XPS, quantitative NMR, operando NMR, cryo-TEM, EELS, and EDS. The interfacial desolvation coating technique enables excellent rate cycling stability (i.e., 1C) of the Li metal anode and prolonged cycling life of the Li||LiCoO 2 pouch cell in the conventional carbonate electrolyte (E/C 2.6 g/Ah), with 80% capacity retention after 333 cycles.

42 ENGINEERING↗
DOE OSTI2021

Building a spontaneously formed and self-healing protective layer with an F-rich electrochemically active organic molecule for ultra-stable Li metal batteries

Additives in the electrolyte act as engineers in Li metal batteries. Inspired by the superior cycle performance of organic materials in half cells, tetrafluoro-1,4-benzoquinone (TFBQ), the main structure of which has been widely applied as an organic cathode material, is utilized for the first time as an additive for Li metal protection. By chemical and electrochemical reactions between TFBQ and the Li metal surface, an F-rich interface layer is in situ formed on the Li metal surface during the charge and discharge process. From electrochemical tests and characterization, the powerful self-healing ability of the interface layer enabled by TFBQ is revealed, making an extremely stable Li metal anode. By using a lean electrolyte with 0.1 M TFBQ, the cycle life of Li|Li symmetric cells is increased at least 6 times compared to the control group. Moreover, impressive full cell performance was achieved. Ultra-stable Li–LFP cells showed a 0.026% average degradation for 600 cycles at 1C and Li–NMC622 cells showed a 36.8% higher capacity compared to the control group over 200 cycles at 0.5C, which are among the best results reported. Furthermore, this work efficiently and conveniently provides a new research direction to Li metal protection and Li metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

A Review of Existing and Emerging Methods for Lithium Detection and Characterization in Li-Ion and Li-Metal Batteries

Whether attempting to eliminate parasitic Li metal plating on graphite (and other Li-ion anodes) or enabling stable, uniform Li metal formation in ‘anode-free’ Li battery configurations, the detection and characterization (morphology, microstructure, chemistry) of Li that cannot be reversibly cycled is essential to understand the behavior and degradation of rechargeable batteries. In this review, various approaches used to detect and characterize the formation of Li in batteries are discussed. Each technique has its unique set of advantages and limitations, and works towards solving only part of the full puzzle of battery degradation. Going forward, multimodal characterization holds the most promise towards addressing two pressing concerns in the implementation of the next generation of batteries in the transportation sector (viz. reducing recharging times and increasing the available capacity per recharge without sacrificing cycle life). Such characterizations involve combining several techniques (experimental- and/or modeling-based) in order to exploit their respective advantages and allow a more comprehensive view of cell degradation and the role of Li metal formation in it. Additionally, it is also discussed which individual techniques, or combinations thereof, can be implemented in real-world battery management systems on-board electric vehicles for early detection of potential battery degradation that would lead to failure.

25 ENERGY STORAGE↗
DOE OSTI2024

Comparative Analysis of Reactivity of Al and Ga Doped Garnet Solid State Electrolyte at the Interface with Li Metal

Lithium garnet (Li 7 La 3 Zr 2 O 12 , LLZO) based solid electrolytes are leading candidate materials for all-solid-state batteries with lithium metal anodes because of their high ionic conductivity, high mechanical toughness, and superior electrochemical stability. While doping LLZO with Al and Ga increases its ionic conductivity by stabilizing the cubic phase, the impact of dopants on its (electro)chemical stability at the interfaces with Li metal is critical. Here, our study of differences between Al- and Ga-doped LLZO when interfaced with lithium metal using X-ray photoelectron spectroscopy and density functional theory shows a higher propensity of Ga to move across LLZO interface with Li metal and form Ga-Li alloy. Additionally, neutron diffraction reveals loss of cubic phase resulting from the loss of dopant that explains electrochemical behavior differences between Ga- and Al-doped LLZO. Overall, our study reveals the key role of dopant chemistry in enabling stable solid electrolyte materials for all-solid-state batteries.

Klenk, Matthew↗
DOE OSTI2020

Li-Metal Anode in Dilute Electrolyte LiFSI/TMP: Electrochemical Stability Using Ab Initio Molecular Dynamics

Ab initio molecular dynamics simulations were performed for Li + conducting electrolytes based on trimethyl phosphates (TMP) and lithium bis(fluorosulfonyl)imide (Li + FSI – ) salt in contact with a Li-metal electrode. We focused on the transient-state behavior at the electrolyte, interfacial electrolyte–Li-metal electrode, and lithium reference electrode–electrolyte–Li-metal electrode to study dynamics and activation energy barriers of the Li + ion, electrochemical and thermal stability of the interface electrode-electrolyte, and potential behavior of the Li-metal electrode, respectively. Our results show that in the most stable state, Li + ions are tetrahedrally coordinated to three TMPs and one FSI – . The inner solvation shell of a Li-ion is composed of three TMP and one FSI – in one contact ion-pair and four TMPs in a solvent-separated ion-pair. On the other hand, Li-ions transport through electrolyte cages takes place when they are coordinated with three or less molecules that could be a combination of TMPs and FSI – . The decomposition pathway of the LiFSI salt when in direct contact with the Li-metal anode starts with defluorination of FSI – , rapidly losing F– to the lithium surface, forming LiF species. The remaining FSO 2 NSO 2 –2 with the addition of 2e – from the Li-metal decomposes into SO 2 –2 and NFSO 2 –2 . SO 2 –2 deposits on the Li-surface and decomposes into Li 2 O and Li 2 S. The remaining NFSO 2 –2 defluorinates, losing F – ion to the lithium surface, resulting in LiF and the remaining NSO 2 –1 deposits on the lithium surface and decomposes in the following picoseconds, forming several binary compounds such as Li 3 N, Li 2 S and Li 2 O. In contrast, when the salt is solvated by the TMP molecules, avoiding a direct contact with the Li metal electrode, only one defluorination occurs, decomposing the FSI – into FSO 2 NSO 2 –2 and a F – . The two anions remain stable as they are solvated by the TMP molecules. Furthermore, we also analyzed the open circuit potential energy (OCPE) of the Li-metal electrode during the SEI formation. OCPE is calculated from the average local potential profile difference within the Li-metal electrode and a pristine Li-crystal reference electrode (LRE). When no SEI is formed, the Li-metal electrode has an average OCPE of +0.36 eV vs LRE. Due to the formation of a SEI, the Li-metal electrode has an average OCPE between -0.07 and -0.21 eV vs LRE. The OCPE of the Li-metal electrode decreases by ~0.42 eV when a SEI is formed.

25 ENERGY STORAGE↗
DOE OSTI2020

Electroanalytical Measurement of Interphase Formation at a Li Metal–Solid Electrolyte Interface

The interphase between Li metal and solid electrolytes dictates performance in Li metal batteries. For the solid electrolyte Lipon, in this study we electroanalytically measure a capacity loss of 1.03 ± 0.16 μAh/cm 2 when Lipon first contacts Li metal. Assuming this capacity is all lost to interphase formation, this corresponds to a maximum Li consumption of 5.0 ± 0.8 nm to form an interphase ~4.7 nm thick. From dynamic electrochemical impedance spectroscopy (dEIS) during Li plating, we determine that nonlinear chaotic spectra demark this interphase formation and that this occurs immediately upon initiation of Li plating. dEIS also reveals interfacial resistance during both plating and stripping that decreases as the amount of plated Li increases.

25 ENERGY STORAGE↗
DOE OSTI2019

Scalable Polymer Precursor Based LiPON Type Li-Metal Interface Enabled High Performance Li-Sulfur Battery

The Battery 500 program objective is to research, develop, and demonstrate lithium battery technologies capable of achieving 500 Wh/kg with stable lifetime of 1000 cycles. This Battery 500 seedlings project has demonstrated a new approach and a pathway toward the program’s goals in just one awarded and executed phase. Cells have been assembled, tested, and evaluated. This report details efforts to develop polymer precursor electrolytes that offer properties anticipated to be similar or superior to LiPON glasses. Such precursors offer the potential to be used to process LiPON-like thin glass/ceramic coatings for use in lithium batteries. LiPON glasses provide a design basis for the synthesis of sets of oligomers/polymers by lithiation of OP(NH 2 ) 3-x (NH) x [from OP(NH) 3 ], OP(NH 2 ) 3-x (NHSiMe 3 ) x and [P=N] 3 (NHSiMe 3 ) 6-x (NH) x . Polymer electrolytes impregnated in/on celgard exhibit Li+ conductivities up to ~1×10 -5 S/cm at room temperature and are thermally stable to ≈150 °C. A Li-S battery assembled using a Li 6 SiPON composition polymer electrolyte exhibits an initial reversible capacity of 1500 mAh/g sulfur and excellent cycle performance at 0.25 and 0.5 C rate over 120 cycles, declining to 750 mAh/g at after a 220 h test period. At the same time, computational studies were performed to understand the conduction mechanism of LIPON and its interaction with Li metal. These initial project results provide a foundation for further development of the system to achieve the program goal.

25 ENERGY STORAGE↗
DOE OSTI2019

Electrochemically Responsive Self-Formed Li-ion Conductors for High Performance Li Metal Anodes

The project will develop and optimize organo-Li x S y , organo-Li x P y S z , and organo-Li x S y /organo-Li x P y S z composite materials as protective layers for Li metal anodes in Li-S batteries. The core focus will be on synthesis methods and precursors for new organic/inorganic hybrid Li-ion conductors, protective layer composition, and protective layer fabrication methods. This will be accompanied by property measurement and characterization (conductivity, mechanical properties, etc.) for the protective layer on Li metal, as well as detailed diagnostics and cell testing. At the conclusion of the project, twelve ~300 mAh pouch cells will be delivered which use the optimal protection layer.

25 ENERGY STORAGE↗