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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Surface Oxygen Depletion of Layered Transition Metal Oxides in Li-Ion Batteries Studied by Operando Ambient Pressure X-ray Photoelectron Spectroscopy

A new operando spectro-electrochemical setup was developed to study oxygen depletion from the surface of layered transition metal oxide particles at high degrees of delithiation. An NCM111 working electrode was paired with a chemically delithiated LiFePO 4 counter electrode in a fuel cell-inspired membrane electrode assembly (MEA). A propylene carbonate-soaked Li-ion conducting ionomer served as an electrolyte, providing both good electrochemical performance and direct probing of the NCM111 particles during cycling by ambient pressure X-ray photoelectron spectroscopy. The irreversible emergence of an oxygen-depleted phase in the O 1s spectra of the layered oxide particles was observed upon the first delithiation to high state-of-charge, which is in excellent agreement with oxygen release analysis via mass spectrometry analysis of such MEAs. By comparing the metal oxide-based O 1s spectral features to the Ni 2p 3/2 intensity, we can calculate the transition metal-to-oxygen ratio of the metal oxide close to the particle surface, which shows good agreement with the formation of a spinel-like stoichiometry as an oxygen-depleted phase. This new setup enables a deeper understanding of interfacial changes of layered oxide-based cathode active materials for Li-ion batteries upon cycling.

25 ENERGY STORAGE↗
DOE OSTI2021

Enabling High-Performance NASICON-Based Solid-State Lithium Metal Batteries Towards Practical Conditions

Solid-state lithium metal batteries (SSLMBs) are promising next-generation high-energy rechargeable batteries. However, the practical energy densities of the reported SSLMBs have been significantly overstated due to the use of thick solid-state electrolytes, thick lithium (Li) anodes, and thin cathodes. Here, a high-performance NASICON-based SSLMB using a thin (60 µm) Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) electrolyte, ultrathin (36 µm) Li metal, and high-loading (8 mg cm -2 ) LiFePO 4 (LFP) cathode is reported. The thin and dense LAGP electrolyte prepared by hot-pressing exhibits a high Li ionic conductivity of 1 × 10 -3 S cm -1 at 80 °C. The assembled SSLMB can thus deliver an increased areal capacity of ≈1 mAh cm -2 at C/5 with a high capacity retention of ≈96% after 50 cycles under 80 °C. Furthermore, it is revealed by synchrotron X-ray absorption spectroscopy and in situ high-energy X-ray diffraction that the side reactions between LAGP electrolyte and LFP cathode are significantly suppressed, while rational surface protection is required for Ni-rich layered cathodes. This study provides valuable insights and guidelines for the development of high-energy SSLMBs towards practical conditions.

25 ENERGY STORAGE↗
DOE OSTI2019

Re-Engineering Poly(Acrylic Acid) Binder toward Optimized Electrochemical Performance for Silicon Lithium-Ion Batteries: Branching Architecture Leads to Balanced Properties of Polymeric Binders

Silicon is a promising anode material for lithium-ion batteries with its superior capacity. However, the drastic volume changes during lithiation/delithiation cycles hinder the cycling performance, resulting in particle pulverization, conductivity loss, and an unstable electrode-electrolyte interface. In this work, a series of synthetic polymeric binders, poly(acrylic acid-co-tetra(ethylene glycol) diacrylate)-featuring a poly(acrylic acid) (PAA) backbone branched via tetra(ethylene glycol) diacrylate (TEGDA)-are developed that edge toward evidencing well-balanced properties to confront capacity fading in Si-based electrodes. The incorporation of ether chain not only leads to the branching architecture of the PAA backbone, thus affecting its mechanical properties, but also promotes the conductivity of Li ions. As a result, a synergistic performance improvement is observed in both half and full cells. The best-performing cell using a branched PAA binder (bPAA) with a feeding molar ratio ([TEGDA]:[acrylic acid(AA)]) of 0.2 results in a 10% increase in initial capacity and a 31% increase in capacity retention over 100 cycles compared to the linear PAA cell. The cross-sectional microscopic images of the cycled electrodes reveal that bPAA binders can drastically reduce the electrode expansion. This improvement results from the well-balanced properties of the polymer design, which could guide further development for more advanced binder materials.

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↗
DOE OSTI2024

The Microscopic Mechanism of Lithiation and Delithiation in the Ag/C Buffer Layer for Anode‐Free Solid‐State Batteries

Abstract Lithium metal solid‐state batteries (LMSSBs) have demonstrated their high energy density and cycling performance at high current densities in an anode‐free architecture, featuring a thin Ag/C composite buffer layer (BL) between the current collector (CC) and the solid electrolyte (SE). This study explains the microscopic mechanism of the Ag/C BL by using first‐principles atomistic and continuum modeling. It is shown that Ag effectively acts as a homogeneous solid‐solution beyond AgLi 2.32 and maintains a positive potential even at AgLi 25 during lithiation. Key factors underlying the working of the Ag/C BL include lower interfacial resistance at the BL/CC interface than at the BL/SE interface, leading to predominant Li deposition on BL/CC, and substantial Ag–Li volume expansion during lithiation. This, combined with stronger BL/SE adhesion, causes BL/SE separation and Ag–Li extrusion toward the CC side. During delithiation, Ag re‐precipitates as nanoparticles uniformly on the CC, with its positive lithiation potential homogenizing Li currents in subsequent cycles. Other metals are less effective due to their relatively large overpotential, premature lithiation termination, and limited volume expansions hindering movement toward the CC. The study aids the BL design, focusing on metal choice and optimization material and microstructural properties, such as the Li‐ion conductivity and interfacial resistance.

25 ENERGY STORAGE↗
DOE OSTI2023

Silver-carbon interlayers in anode-free solid-state lithium metal batteries: Current development, interfacial issues, and instability challenges

As an interlayer between the anode and the electrolyte of the all-solid-state lithium metal batteries (ASSLMBs), the silver-carbon (Ag-C) nanocomposite has been reported to significantly increase the energy density and cycle rate of solid-state lithium metal batteries. Ag-C interlayers serve as mixed ionic-electronic conductor that conducts both Li+ ions and electrons and lithium storage capacity. Unfortunately, it was unclear how the Ag-C interlayer regulated lithium plating and stripping. Moreover, the structural and chemical instabilities between the interlayer and the electrolyte, within the interlayer, or beneath the interlayer on lithium substrate are likely to cause cell failure. In this review, we discuss interfacial issues and summarize recent progress in solution strategies for ASSLMBs, with a specific focus on the use of a silver-carbon (Ag-C) nanocomposite interlayer in anode-free setups. Based on the Li transport kinetics among the Ag-C interlayers, the interfacial configurations of Ag-C interlayers are classified as either exterior or internal. Furthermore, the review concludes with a discussion of the perspectives and future prospects, allowing for the improvement of interlayer techniques for solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

Size-Dependent Chemomechanical Failure of Sulfide Solid Electrolyte Particles during Electrochemical Reaction with Lithium

The very high ionic conductivity of Li 10 GeP 2 S 12 (LGPS) solid electrolyte (SE) makes it a promising candidate SE for solid-state batteries in electrical vehicles. However, chemomechanical failure, whose mechanism remains unclear, has plagued its widespread applications. Here, we report in situ imaging lithiation-induced failure of LGPS SE. In this work, we revealed a strong size effect in the chemomechanical failure of LGPS particles: namely, when the particle size is greater than 3 μm, fracture/pulverization occurred; when the particle size is between 1 and 3 μm, microcracks emerged; when the particle size is less than 1 μm, no chemomechanical failure was observed. This strong size effect is interpreted by the interplay between elastic energy storage and dissipation. Our finding has important implications for the design of high-performance LGPS SE, for example, by reducing the particle size to less than 1 μm the chemomechanical failure of LGPS SE can be mitigated.

25 ENERGY STORAGE↗
DOE OSTI2024

3D Printed Nanoporous Separators Based on Polymerization-Induced Phase Separation for Fast-Charging, High Cycling Stability Li-Ion Batteries

Fast charging and stable lithium-ion batteries (LIBs) require prompt Li ion transport between electrodes. 3D porous separators can potentially improve ion transport at both the microscale and macroscale levels. Additive manufacturing (AM) is an ideal tool to produce and study 3D porous separators of LIBs, although little work has been reported in this area. Here, we demonstrate porous structural control in layer-by-layer printed hexanediol diacrylate (HDDA) separators using a projection micro stereolithography (PμSL) AM technology and present their corresponding battery performance in lithium nickel manganese cobalt oxide (NMC)/graphite full cells. The composition of photocurable resin determines the porous morphology (e.g., bicontinuous and droplet-like), while the settings of printing layer thickness and number of exposures can be used to adjust the porosity (e.g., from 27% to 63%). Optimal resin and print conditions are determined, and the resulting separator exhibits superior Li ion conductivity and therefore higher rate performance and longer cycling life. Compared with a Celgard 2325 separator, the optimized porous HDDA separator increases the 10C-rate capacity by 34% and decreases the capacity degradation rate at the 1C-rate by 4.9%. In conclusion, this work paves the way for future AM of 3D separators for high-energy, high-power, and long-cycling-life LIBs.

25 ENERGY STORAGE↗
DOE OSTI2026

Observation of N-rich solid-electrolyte interphase by ToF-SIMS.

Formation of a stable solid electrolyte interphase (SEI) between lithium electrodes and electrolyte upon multiple charge/discharge cycles is crucial to a long-term lithium-ion battery performance. Addition of LiNO3 to lithium bis (fluorosulfonyl) imide/poly(ethylene oxide) (LiFSI/PEO) electrolyte leads to a durable SEI that is electrically insulating yet highly conductive to Li ions, chemically and electrochemically stable, physically uniform, and mechanically robust. ToF-SIMS was used here in combination with sputtering by a gaseous cluster ion beam (GCIB) to examine how the addition of a small proportion of LiNO3 to the LiFSI/PEO electrolyte affects the SEI composition. Negative ion ToF-SIMS spectra of the cycled samples display an intense m/z 26 peak associated with the SEI. Exact mass assignments and isotopic ratios indicate that this peak should be assigned as (CN-)-C-12, with little to no negative secondary ion signal arising from (LiF-)-Li-7. This CN- signal appears to arise from an N-rich portion of the SEI adjacent to the Li electrode that is depleted in LiF relative to the bulk electrolyte. The dearth of LiF- (and LiF+ from the positive ion spectra) is unexpected because LiF has been identified in the SEI in similar samples. Finally, GCIB sputtering indicates that the SEI adheres more strongly to the Li electrode than to the LiFSI/PEO electrolyte.

Shavandi, Seyedeh Reyhaneh↗
DOE OSTI2022

Performance of Lithium-Ion Batteries with 3D Printed Anodes and Compressible Carbon Structures

Carbon scaffolds have been shown to improve the performance of Li metal anodes in Li-ion batteries by acting as conductive hosts for Li metal plating and stripping. The scaffolds provide a more uniform electric field, and their 3D geometry enables smaller diffusion paths for the Li ions. In this project, several different types of carbon lattices were 3D printed, mechanically tested, and analyzed in coin cells. Planar and 3D printed graphite coatings were evaluated as the baseline, since graphite is a common anode material. The results showed that implementing a 3D graphite lattice into a coin cell improved the Li plating and stripping efficiency compared to the planar coating. However, since graphite can intercalate Li ions, other carbon materials were also explored that should act as better hosts for Li plating/stripping. To improve the compressibility of these non-graphite carbon scaffolds, five different carbon ink formulations were 3D printed in lattice configurations. SEM imaging and compression testing showed that both the final dimensions and the compressibility of the carbon lattices depended on the type of carbon precursors used. The two most suitable compositions were found to be those made with graphene oxide-resorcinol formaldehyde and graphene oxide-ammonium hydroxide. In the future, these formulations will be further refined to increase their mechanical strength, and their performance as scaffold hosts for Li metal anodes will be evaluated in coin cells.

25 ENERGY STORAGE↗
DOE OSTI2024

Glassy embedded solid-state electrode assemblies, solid-state batteries and methods of making electrode assemblies and solid-state batteries

Batteries, component structures and manufacturing methods, in particular including a glassy embedded battery electrode assembly having a composite material structure composed of interpenetrating material components including a porous electroactive network including a solid electroactive material, and a continuous glassy medium including a Li ion conducting sulfide glass, can achieve enhanced power output, reduced charging time and/or improved cycle life.

Visco, Steven J.↗
DOE OSTI2024

Effects of Al concentration on the structure and conductivity of lithium lanthanum zirconium oxide

Cubic Li 7-3x Al x La 3 Zr 2 O 12 (LLZO) is a promising, next-generation solid electrolyte due to its stability with Li-metal and high bulk conductivity (~1 mS cm -1 ). However, the source of the high conductivity is not completely understood. In this work, we address this key knowledge gap through the integration of elemental analysis, neutron diffraction sensitive to Li and O atoms, and impedance spectroscopy to understand the structure–property correlations for LLZO. We show the metal–oxygen framework structure remains constant with variation in Al substitution, resulting in a constant activation energy of ~0.35 eV and little effect on the bulk conductivity. Instead, Li concentration, Al blocking and trapping of mobile defects, and Li–Li nearest neighbor interactions largely control the Al substituted LLZO bulk conductivity, resulting in decreases from 0.73 to 0.22 mS cm -1 as the Al concentration increases from 0.17 to 0.32 mol. These results differ from those of Ta substituted LLZO, where the framework structure and Li–Li site distances play large roles in controlling the conductivity. The increased understanding of the controlling factors of conductivity allows for greater ability to tailor the design of and substitution into the LLZO structure for improved conductivity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Superionic conducting vacancy-rich β-Li 3 N electrolyte for stable cycling of all-solid-state lithium metal batteries

The advancement of all-solid-state lithium metal batteries requires breakthroughs in solid-state electrolytes (SSEs) for the suppression of lithium dendrite growth at high current densities and high capacities (>3 mAh cm -2 ) and innovation of SSEs in terms of crystal structure, ionic conductivity and rigidness. Here we report a superionic conducting, highly lithium-compatible and air-stable vacancy-rich β-Li 3 N SSE. This vacancy-rich β-Li 3 N SSE shows a high ionic conductivity of 2.14 × 10 -3 S cm -1 at 25 °C and surpasses almost all the reported nitride-based SSEs. A Li- and N-vacancy-mediated fast lithium-ion migration mechanism is unravelled regarding vacancy-triggered reduced activation energy and increased mobile lithium-ion population. All-solid-state lithium symmetric cells using vacancy-rich β-Li 3 N achieve breakthroughs in high critical current densities up to 45 mA cm -2 and high capacities up to 7.5 mAh cm -2 , and ultra-stable lithium stripping and plating processes over 2,000 cycles. The high lithium compatibility mechanism of vacancy-rich β-Li 3 N is unveiled as intrinsic stability to lithium metal. In addition, β-Li 3 N possesses excellent air stability through the formation of protection surfaces. All-solid-state lithium metal batteries using the vacancy-rich β-Li 3 N as SSE interlayers and lithium cobalt oxide (LCO) and Ni-rich LiNi 0.83 Co 0.11 Mn 0.06 O 2 (NCM83) cathodes exhibit excellent battery performance. Extremely stable cycling performance is demonstrated with high capacity retentions of 82.05% with 95.2 mAh g -1 over 5,000 cycles at 1.0 C for LCO and 92.5% with 153.6 mAh g -1 over 3,500 cycles at 1.0 C for NCM83. Utilizing the vacancy-rich β-Li 3 N SSE and NCM83 cathodes, the all-solid-state lithium metal batteries successfully accomplished mild rapid charge and discharge rates up to 5.0 C, retaining 60.47% of the capacity. Notably, these batteries exhibited a high areal capacity, registering approximately 5.0 mAh cm -2 for the compact pellet-type cells and around 2.2 mAh cm -2 for the all-solid-state lithium metal pouch cells.

25 ENERGY STORAGE↗
DOE OSTI2026

Li + /H + Exchange in Solid-State Oxide Li-Ion Conductors

Understanding the moisture stability of oxide Li-ion conductors is important for their practical applications in solid-state batteries. Unlike sulfide or halide conductors, oxide conductors generally better resist degradation when in contact with water but can still undergo topotactic Li + /H + exchange (LHX). Here, we combine density functional theory (DFT) calculations with a machine-learning interatomic potential model to investigate the thermodynamic driving force of the LHX reaction for two representative oxide Li-ion conductor families: garnets and NASICONs. Li-stuffed garnets exhibit a strong driving force for proton exchange due to their high Li chemical potential. In contrast, NASICONs demonstrate a higher resistance against proton exchange due to the lower Li chemical potential and the lower O–H bond covalency for polyanion-bonded oxygens. Our findings reveal a critical trade-off: Li stuffing enhances conductivity but increases moisture susceptibility. This study underscores the importance of designing Li-ion conductors that possess both high conductivity and high stability in practical environments.

Li, Zhuohan [Lawrence Berkeley National Laboratory↗
DOE OSTI2022

Nanoscale Li, Na, and K ion-conducting polyphosphazenes by atomic layer deposition

A key trailblazer in the development of thin-film solid-state electrolytes has been lithium phosphorous oxynitride (LiPON), the success of which has led to recent progress in thin-film ion conductors. Here we compare the structural, electrochemical, and processing parameters between previously published LiPON and NaPON ALD processes with a novel ALD process for the K analogue potassium phosphorous oxynitride (KPON). In each ALD process, alkali tert-butoxides and diethylphosphoramidate are used as precursors. To understand the ALD surface reactions, this work proposes a reaction mechanism determined by in-operando mass spectrometry for the LiPON process as key to understanding the characteristics of the APON (A = Li, Na, K) family. As expected, NaPON and LiPON share similar reaction mechanisms as their structures are strikingly similar. KPON, however, exhibits similar ALD process parameters but the resulting film composition is quite different, showing little nitrogen incorporation and more closely resembling a phosphate glass. Due to the profound difference in structure, KPON likely undergoes an entirely different reaction mechanism. Furthermore, this paper presents a comprehensive summary of ALD ion conducting APON films as well as a perspective that highlights the versatility of ALD chemistries as a tool for the development of novel thin film ion-conductors.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

The role of Li doping in layered/layered Na x Li y Ni 0.4 Fe 0.2 Mn 0.4 O 2 intergrowth electrodes for sodium ion batteries

Here, the layered NaTMO 2 (TM = Ni, Fe, Mn) materials with the O3-type structure are attractive as positive electrodes for sodium ion batteries because of their high theoretical capacity. Additionally, Li doping in these materials has been shown to offer substantial enhancements to their electrochemical properties by promoting the formation of intergrowth structures, which are combinations of specific phases. However, the mechanism by which the intergrowth modifies the electrochemical properties is often unclear. Systematic variation of Li content in Na x Li y Ni 0.4 Fe 0.2 Mn 0.4 O 2 (NFM-Li y ) was conducted to identify its role in structural modification and electrochemical performance. Li contents of 0.15 and greater generate a layered/layered Na-O3/Li-O’3 intergrowth structure. 7 Li and 23 Na nuclear magnetic resonance and x-ray absorption spectroscopy identify that when the total solubility for alkali ions in the layered structure is exceeded, Li continues to form the Li-O’3 phase while the excess Na forms residual sodium compounds such as Na 2 O. Higher Li content is associated with improved capacity retention in the initial cycles from the superior stability of the mechanically linked NaO3/Li-O’3 structure that suppresses the P3 to OP2 phase transition during charge. However, high Li contents are associated with increased rates of parasitic side reactions that reduce long-term cycling stability. These side reactions are associated with the instability of the cathode-electrolyte interphase, which can be partially mitigated by atomic layer deposition (ALD) coating with alumina, which significantly enhances the capacity retention and Coulombic efficiency over many cycles. Overall, we find that the layered/layered Na-O3/Li-O’3 intergrowth structure is able to provide structural stability and suppress undesired phase transformations but is overwhelmed by the increased reactivity of the surface if not protected by surface coating.

25 ENERGY STORAGE↗