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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

A Quasi-Ordered Mn-Rich Cathode with Highly Reversible Oxygen Anion Redox Chemistry

Anionic oxygen redox chemistry in Li-rich Mn-based layer oxide cathodes represents a transformative approach for boosting the energy density of next-generation lithium-ion batteries. However, conventional oxygen redox reactions often induce oxygen dimerization at high voltages, leading to irreversible lattice oxygen loss and a rapid voltage fade. Herein, we achieve highly reversible oxygen redox chemistry through a new quasi-ordered structural design that incorporates both intra- and interlayer cation disorder configurations. This unique structure significantly enhances lattice oxygen stability, effectively stabilizes oxidized oxygen, and inhibits the formation of peroxo- or superoxol-like species, thereby enabling anionic redox reactions to proceed reversibly even at deep delithiation states. The quasi-ordered design mitigates irreversible phase transitions and preserves the structural integrity throughout extended cycling. Consequently, the proposed cathode demonstrates exceptional cyclability with negligible capacity and voltage fade, retaining 99% capacity and 98% average voltage after long-term cycling. Finally this work provides fresh insights into addressing issues related to lattice oxygen instabilities and reforming strategies for developing long-life, high-energy-density anionic redox cathode materials for advanced batteries.

chemical structure↗
DOE OSTI2020

Sulfurized Polyacrylonitrile for High-Performance Lithium–Sulfur Batteries: In-Depth Computational Approach Revealing Multiple Sulfur’s Reduction Pathways and Hidden Li + Storage Mechanisms for Extra Discharge Capacity

Like no other sulfur host material, polyacrylonitrile-derived sulfurized carbon (SPAN) promises improved electrochemical performance for lithium–sulfur batteries, based on its compatibility with carbonate solvents and ability to prevent self-discharge and shuttle effect. However, a complete understanding of the SPAN’s lithiation mechanism is still missing because its structural features vary widely with synthesis conditions, and its electrochemical performance deviates from elemental sulfur. This study continues our research on the elucidation of the SPAN’s structural characteristics and lithiation mechanisms via computational approaches. Here, our models reproduce most experimental data regarding carbon’s graphitization level and conjugated ordering, sulfur–carbon covalent bonding, sulfur loading, and elemental composition. Our simulations emulate the discharge voltage observed in experiments for the first discharge, which reveals that sulfur follows multiple reduction pathways based on its interaction with the carbon backbone. Sulfur reduction takes place above 1.0 V vs Li/Li + mostly in the SPAN-like material, with no long-chain lithium polysulfide formation. Below 1.0 V vs Li/Li + , the backbone’s electrochemical activity occurs via multiple C–Li and N–Li interactions, mostly with edge carbon atoms and pyridinic nitrogen. Moreover, we identify Li + binding sites throughout the graphitized backbone that might lead to prohibited energy costs for Li + deintercalation, which may explain the irreversible capacity loss between the first and second discharges. This work improves understanding of lithiation mechanisms in sulfurized carbon, which is useful for rationally designing SPAN synthesis pathways tailored to increase sulfur loading and enhanced electrochemical performance.

25 ENERGY STORAGE↗
DOE OSTI2022

Constructing O2/O3 homogeneous hybrid stabilizes Li-rich layered cathodes

With the advantages of high energy density and low manufacture cost, lithium-rich layered oxides (LLOs), typically with a layered O3-type structure, are regarded as promising cathodes for lithium-ion batteries (LIBs), but their broad usages are hindered by severe voltage decay over cycling. Although recent progress in O2-type LLOs has aroused interest for their less voltage decay, the critical barrier of unsatisfactory capacity retention has not been overcome yet. In this work, to tackle these handicaps, we design a new type of LLO (O2/O3-type LLO) with a homogeneous hybrid structure, where the O2 and O3 lattice stacking sequences are arranged alternatively. Benefitting from this novel O2/O3 hybrid structure, the designed material shows greatly improved voltage and capacity stability than that of pure O2- and O3-type LLOs. Revealed by in-situ synchrotron X-ray diffraction and operando differential electrochemical mass spectra, the O2/O3-hybrid LLO cathode shows a more reversible structural evolution, smaller volume change and suppressed oxygen loss during the electrochemical processes. Our approach has initiated a new way to reduce the capacity and voltage decay of LLOs, which endows great promise to the development of high-energy-density LIBs.

25 ENERGY STORAGE↗
DOE OSTI2023

Precise Tailoring of Lithium-Ion Transport for Ultralong-Cycling Dendrite-Free All-Solid-State Lithium Metal Batteries

All-solid-state lithium metal batteries can address crucial challenges regarding insufficient battery cycling life and energy density. The demonstration of long-cycling dendrite-free all-solid-state lithium metal batteries requires precise tailoring of lithium-ion transport of solid-state electrolytes (SSEs). Here, in this work, a proof of concept is reported for precise tailoring of lithium-ion transport of a halide SSE, Li 3 InCl 6 , including intragranular (within grains) but also intergranular (between grains) lithium-ion transport. Lithium-ion migration tailoring mechanism in crystals is developed by unexpected enhanced Li, In, and Cl vacancy populations and lower energy barrier for hopping. The lithium-ion transport tailoring mechanism between the grains is determined by the elimination of voids between grains and the formation of unexpected supersonic conducting grain boundaries, boosting the lithium dendrite suppression ability of SSE. Due to boosted lithium-ion conduction and dendrite-suppression ability, the all-solid-state lithium metal batteries coupled with Ni-rich LiNi 0.83 Co 0.12 Mn 0.05 O 2 cathodes and lithium metal anodes demonstrate breakthroughs in electrochemical performance by achieving extremely long cycling life at a high current density of 0.5 C (2000 cycles, 93.7% capacity retention). This concept of precise tailoring of lithium-ion transport provides a cost, time, and energy efficient solution to conquer the remaining challenges in all-solid-state lithium-metal batteries for fast developing electric vehicle markets.

25 ENERGY STORAGE↗
NASA NTRS1985

High cycle life secondary lithium battery

A secondary battery (10) of high energy density and long cycle is achieved by coating the separator (18) with a film (21) of cationic polymer such as polyvinyl-imidazoline. The binder of the positive electrode (14) such as an ethylene-propylene elastomer binder (26) containing particles (28) of TiS.sub.2 chalcogenide can also be modified to contain sulfone functional groups by incorporating liquid or solid sulfone materials such as 0.1 to 5 percent by weight of sulfolane into the binder. The negative lithium electrode (14), separator (18) and positive electrode (16) are preferably spirally wound and disposed within a sealed casing (17) containing terminals (32, 34). The modified separator and positive electrode are more wettable by the electrolytes in which a salt is dissolved in a polar solvent such as sulfolane.

Yen, Shiao-Ping S.↗
DOE OSTI2023

Electron Delocalization Enables Sulfone-based Single-solvent Electrolyte for Lithium Metal Batteries

Li-metal batteries (LMB), although providing high energy density, face the grand challenge of identifying good electrolyte solvents for cycling. Common solvents are either only stable against lithium metal anode or only stable against LiNi x MnyCo 1-x-y O 2 (NMC) cathode. There is significant effort trying to increase the cathode stability for ether electrolytes, which are in general stable against lithium metal anode. In comparison, there is much less effort trying to increase the anode stability of electrolytes that are stable against NMC cathode. One example is the sulfone-based electrolyte. It has good cathode stability but is hindered from practical application because of (1) high viscosity and poor wetting capability and (2) poor anode stability. Here, we solve these issues by modifying the sulfone molecules using resonance and electron withdrawing effect. The viscosity is significantly reduced by delocalizing the electrons through introducing additional oxygen on the molecular backbone and applying appropriate fluorination. The resulting molecule 2,2,2-trifluoroethyl mesylate (TFEM) has decreased Lewis basicity and less reactivity toward Li + . In conclusion, the electrolyte based on TFEM as single solvent enables cycling of LMB under harsh conditions of low N/P ratio (21 mg/cm 2 NMC811 and 50 μm Li) with 90 % capacity retention after 160 cycles at C/3 discharge rate.

25 ENERGY STORAGE↗
DOE OSTI2023

Electron Delocalization Enables Sulfone-based Single-solvent Electrolyte for Lithium Metal Batteries

Li-metal batteries (LMB), although providing high energy density, face the grand challenge of identifying good electrolyte solvents for cycling. Common solvents are either only stable against lithium metal anode or only stable against LiNi x Mn y Co 1-x-y O 2 (NMC) cathode. There is significant effort trying to increase the cathode stability for ether electrolytes, which are in general stable against lithium metal anode. In comparison, there is much less effort trying to increase the anode stability of electrolytes that are stable against NMC cathode. One example is the sulfone-based electrolyte. It has good cathode stability but is hindered from practical application because of (1) high viscosity and poor wetting capability and (2) poor anode stability. Here, we solve these issues by modifying the sulfone molecules using resonance and electron withdrawing effect. The viscosity is significantly reduced by delocalizing the electrons through introducing additional oxygen on the molecular backbone and applying appropriate fluorination. The resulting molecule 2,2,2-trifluoroethyl mesylate (TFEM) has decreased Lewis basicity and less reactivity toward Li + . The electrolyte based on TFEM as single solvent enables cycling of LMB under harsh conditions of low N/P ratio (21 mg/cm 2 NMC811 and 50 μm Li) with 90 % capacity retention after 160 cycles at C/3 discharge rate.

25 ENERGY STORAGE↗
DOE OSTI2024

Template Assisted Lithium Superoxide Growth for Lithium-Oxygen Batteries

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

Intermetallics↗
DOE OSTI2022

Strain-retardant coherent perovskite phase stabilized Ni-rich cathode

The use of state-of-the-art Ni-rich layered oxides (LiNi x Co y Mn 1-x-y O 2 , x > 0.5) as the cathode material for lithium-ion batteries can push the energy and power density to a higher level than is currently available. However, volume variation associated with anisotropic lattice strain and stress that is being developed during lithium (de) intercalation induces severe structural instability and electrochemical decay of the cathode materials, which is amplified further when the battery is operating at a high voltage (above 4.5 V), which is essential for unlocking its high energy. Even after much effort by the research community, an intrinsic strain-retardant method for directly alleviating the continuous accumulation of lattice strain remains elusive. By introducing a coherent perovskite phase into the layered structure functioning as a ‘rivet’, we significantly mitigate the pernicious structural evolutions by a pinning effect. The lattice strain evolution in every single cycle is markedly reduced by nearly 70% when compared with conventional materials, which significantly enhances morphological integrity leading to a notable improvement in battery cyclability. This strain-retardant approach broadens the perspective for lattice engineering to release the strain raised from lithium (de)intercalation and paves the way for the development of high-energy-density cathodes with long durability.

25 ENERGY STORAGE↗
DOE OSTI2020

Effect of salt concentration profiles on protrusion growth in lithium-polymer-lithium cells

In this report, the formation of dendrites and other protrusions on lithium metal anodes is a subject of continued interest due to the potential to incorporate these anodes in next-generation rechargeable batteries with increased energy densities. Solid polymer electrolytes show improved stability against lithium metal compared to liquid carbonate electrolytes. We have studied the effect of salt concentration on the formation of protrusions formed on electrodeposited lithium through a rigid block copolymer electrolyte, polystyrene-block-poly(ethylene oxide) (PS-b-PEO or SEO), in a lithium-lithium symmetric cell. The cell lifetime decreases by a factor of 100 when salt concentration is increased by a factor of 5. Our main objective is to understand the reason for this observation. We show that this decrease is not due to a salt-induced change of the morphology of the block-copolymer electrolyte, nor is it due to a salt-induced change of mechanical properties. We use an approach based on Newman's concentrated solution theory to fully characterize ion transport in the block-copolymer electrolyte, and report the conductivity, salt diffusion coefficient, cation transference number, and thermodynamic factor. Neither cell lifetime nor protrusion density in failed cells correlate with any of these electrochemical parameters. However, the electrochemical parameters can be used to predict salt concentration profiles in our symmetric cells. We posit that an important parameter in protrusion growth is the magnitude of the salt concentration gradient, Δ. We observe a direct correlation between Δ and lithium protrusion growth.

25 ENERGY STORAGE↗
DOE OSTI2020

Optimization of Oxygen Electrode Combined with Soluble Catalyst to Enhance the Performance of Lithium-Oxygen Battery

Lithium-air batteries possess a high theoretical energy density among the current battery technologies, and are expected to become the driving power for electric vehicles. However, the practical application of lithium air batteries is handicapped by their poor cycle life, high over-charge potential and low energy efficiency. Numerous studies have performed to improve the kinetics of the electrochemical reaction. Making a good oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) catalyst system is under intense scrutiny. In this work, we report a rational design of air electrode, which derives from biomass and presents a three-dimensional porous carbon architecture with high specific surface and large volume expansion coefficient. Combining with a soluble catalyst, this oxygen electrode presents an ultrahigh areal specific capacity of 7.95 mAh/cm 2 and a long cycling life up to 1000 cycles with suppressed polarization (about 0.46 V). Finally, the greatly improved overall performance is due to the synergetic effect of the novel designed oxygen electrode capable of mediating the redox mediators to trigger the ORR and OER process.

25 ENERGY STORAGE↗
NASA NTRS2005

Nanostructured MnO2-Based Cathodes for Li-Ion/Polymer Cells

Nanostructured MnO2-based cathodes for Li-ion/polymer electrochemical cells have been investigated in a continuing effort to develop safe, high-energy-density, reliable, low-toxicity, rechargeable batteries for a variety of applications in NASA programs and in mass-produced commercial electronic equipment. Whereas the energy densities of state-of-the-art lithium-ion/polymer batteries range from 150 to 175 W h/kg, the goal of this effort is to increase the typical energy density to about 250 W h/kg. It is also expected that an incidental benefit of this effort will be increases in power densities because the distances over which Li ions must diffuse through nanostructured cathode materials are smaller than those through solid bulk cathode materials.

Skandan, Ganesh↗
DOE OSTI2025

Valuation of Anode Materials for High-Performance Lithium Batteries: From Graphite to Lithium Metal and Beyond

Lithium-ion batteries have revolutionized energy storage, yet advanced technologies such as electric vehicles and eVTOLs demand even higher performance and safety. Anodes, the negative electrodes, are crucial in enhancing batteries’ safety, lifespan, and fast-charging capabilities. This review paper comprehensively evaluates the progression of anode materials from traditional graphite to advanced anodes like lithium metal. Graphite anodes, with a capacity of 372 mAh g −1 , enabled the first commercial lithium-ion batteries, but future applications require higher energy densities and fast-charging capabilities. Emerging anode materials, including alloying, and conversion types, as well as lithium metal, offer significantly higher capacities, with lithium metal offering a theoretical capacity of 3 860 mAh g −1 . However, these advanced anodes face challenges such as volume expansion, high surface reactivity, sluggish Li+ kinetics, and unstable lithium deposition morphologies. Here, this review critically examines the electrochemical performance, interfacial properties, mechanical attributes, and stability issues of various anode materials. It further discusses solid electrolyte interphase (SEI) formation, strategies for enhancing interface stability, and the requirements of anodes for solid-state batteries. Additionally, the review explores potential solutions for limitations with each anode type, highlights innovative anode-free architectures, and evaluates the current and future trends of battery anode industries. Ultimately, this paper aims to guide the development of high-performance anode materials, paving the way for the next generation of efficient, reliable lithium batteries.

Alloying anodes↗
NASA NTRS1996

High Temperature Analysis of Aluminum-Lithium 2195 Alloy to Aid in the Design of Improved Welding Techniques

Aluminum-lithium alloys have extraordinary properties. The addition of lithium to an aluminum alloy decreases its density, while making large increases in its strength and hardness. The down side is that they are unstable at higher temperatures, and are subsequently difficult to weld or even manufacture. Martin Marietta, though, developed an aluminum-lithium alloy 2195 that was reported to have exceptional properties and good weldability. Thus, it was chosen as the alloy for the space shuttles super light external tank. Unfortunately, welding 2195 has turned out to be much more of a challenge than anticipated. Thus, research has been undergone in order to understand the mechanisms that are causing the welding problems. Gas reactions have been observed to be detrimental to weld strength. Water vapor has often been identified as having a significant role in these reactions. Nitrogen, however, has also been shown to have a direct correlation to porosity. These reactions were suspected as being complex and responsible for the two main problems of welding 2195. One, the initial welds of 2195 are much weaker than the parent metal. Second, each subsequent welding pass increases the size and number of cracks and porosity, yielding significant reductions in strength. Consequently, the objective of this research was to characterize the high-temperature reactions of 2195 in order to understand the mechanisms for crack growth and the formation of porosity in welds. In order to accomplish that goal, an optical hot-stage microscope, HSM, was used to observe those reactions as they occurred. Surface reactions of 2195 were observed in a variety of environments, such as air, vacuum, nitrogen and helium. For comparison, some samples of Al-2219 were also observed. Some of the reacted surfaces were then analyzed on a scanning electron microscope, SEM. Additionally, a gas chromatograph was used to analyze the gaseous products of the high temperature reactions.

Talia, George E.↗
DOE OSTI2021

Interconnected cathode-electrolyte double-layer enabling continuous Li-ion conduction throughout solid-state Li-S battery

All-solid-state lithium (Li) batteries with high energy density are a promising solution for the next-generation energy storage systems in large-scale devices. To simultaneously overcome the challenges of poor ionic conduction of solid electrolytes and shuttling of active materials, here we introduce a functional electrolyte-cathode bilayer framework with interconnected LLAZO channels from the electrolyte into the cathode for advanced solid-state Li-S batteries. Differing from the traditional solid-state batteries with separated layer compositions, the introduced bilayer framework provides ultrafast and continuous ion/electron conduction. Instead of transferring Li+ across the polymer and garnet phases which involve huge interfacial resistance, Li+ is directly conducted through the LLAZO channels created continuously from the cathode layer to the solid electrolyte layer, significantly shortening the diffusion distance and facilitating the redox reaction of sulfur and sulfides. A stable cycle life is demonstrated in the prototype Li-S solid-state batteries assembled with the introduced LLAZO-LLAZO@CNF interconnected bilayer framework. High capacity is obtained at room temperature, indicating the superior electrochemical properties of the bilayer framework that result from the unique design of the interconnected LLAZO garnet phase.

25 ENERGY STORAGE↗
DOE OSTI2022

Limiting Current Density in Single-Ion-Conducting and Conventional Block Copolymer Electrolytes

The limiting current density of a conventional polymer electrolyte (PS-PEO/LiTFSI) and a single-ion-conducting polymer electrolyte (PSLiTFSI-PEO) was measured using a new approach based on the fitted slopes of the potential obtained from lithium-polymer-lithium symmetric cells at a constant current density. The results of this method were consistent with those of an alternative framework for identifying the limiting current density taken from the literature. We found the limiting current density of the conventional electrolyte is inversely proportional to electrolyte thickness as expected from theory. The limiting current density of the single-ion-conducting electrolyte was found to be independent of thickness. There are no theories that address the dependence of the limiting current density on thickness for single-ion-conducting electrolytes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Advanced strategies for the development of porous carbon as a Li host/current collector for lithium metal batteries

Lithium metal is considered a promising anode material for high-energy-density rechargeable batteries because of its high specific theoretical capacity (3860 mAh g -1 , low mass density (0.534 g cm -3 ), and low electrochemical redox potential (-3.04 V vs. the standard hydrogen electrode). However, the high reactivity of Li with the electrolyte leads to the formation of an unstable solid electrolyte interphase (SEI) and continuous side reactions. Also, the non-uniform lithium-ion flux and infinite volume expansion of Li metal cause the growth of Li dendrites. These pose significant safety challenges and cause rapid capacity fading of the lithium metal batteries (LiMBs). To resolve these issues, a low-cost, easily processed, lightweight, high-performance carbon-based porous matrix is considered promising to host Li metal deposition. The three-dimensional (3D) porous nano/microstructured carbon provides sufficient space for Li accommodation during Li plating, buffers the volume changes during Li plating/stripping, and lowers the effective current density contributing to dendrite-free Li deposition. Besides, the outstanding electrochemical and mechanical stability, flexibility and the high electronic conductivity enable the nano/microstructured carbon to serve as both Li host and current collector. The development of 3D carbon/Li composite by mechanical roll-press techniques not only eliminates the complex and risky procedure of making carbon/Li composite based on Li plating or molten Li infusion but also stabilizes the capacity at higher Li plating/stripping rates. Recently, there is an advancement in the lithiophilic decorations of 3D structure to introduce sufficient nucleation sites and the development of artificial SEI on top of the 3D matrix to suppress Li dendrite formation. Such 3D structural modifications create a uniform electric field, lower the Li nucleation overpotential, provide strong mechanical and chemical stability, and stabilize the interface thereby inhibiting the degradation of lithium and the electrolyte. Here we summarize the research progress on porous carbon/Li composites in terms of materials type, structure, fabrication technique, their electrochemical battery performance, and identify the critical challenges that need to be addressed for high-energy-density practical LiMBs.

25 ENERGY STORAGE↗