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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Dual Passivation of Cathode and Anode through Electrode–Electrolyte Interface Engineering Enables Long-Lifespan Li Metal–SPAN Batteries

The reliability and durability of lithium metal (Li 0 )–sulfur batteries are largely limited by the undesired Li 0 plating-stripping irreversibility and the detrimental polysulfide dissolution, yet approaches that can simultaneously address the above anodic and cathodic problems are scarce. In this study, we report the stable operation of a Li 0 -SPAN (sulfurized polyacrylonitrile) battery via an anode–cathode dual-passivation approach. By combination of a fluorinated localized high concentration electrolyte (LHCE) and a Li 3 N-forming additive (TMS-N 3 ), robust and highly conductive electrode passivation layers are formed in situ on the surface of both the Li 0 anode and the SPAN cathode. The resulting highly reversible, dendrite-free, and high-density Li 0 plating morphology enables a high Coulombic efficiency of 99.4%. Advanced tender energy X-ray spectroscopy also reveals the eliminated Li 2 S formation and minimized polysulfide dissolution in SPAN cathodes, leading to a high capacity of 580 mAh/g SPAN and stable cycling with negligible capacity decay (0.7%) for 800 cycles. This electrode–electrolyte interphase engineering strategy has tackled the major limitations of Li–S batteries in both ether- and carbonate-based electrolyte systems and under a wide temperature range from –10 to +50 °C, thus providing insightful guidelines for the rational design of highly durable and high-energy-density Li 0 -S batteries.

25 ENERGY STORAGE↗
DOE OSTI2021

Optimization of Magnesium‐Doped Lithium Metal Anode for High Performance Lithium Metal Batteries through Modeling and Experiment

Abstract Lithium (Li)‐magnesium (Mg) alloy with limited Mg amount, which can also be called Mg‐doped Li (Li‐Mg), has been considered as a potential alternative anode for high energy density rechargeable Li metal batteries. However, the optimum doping‐content of Mg in Li‐Mg anode and the mechanism of the improved performance are not well understood. Herein, density functional theory (DFT) calculations are used to investigate the effect of Mg amount in Li‐Mg anode. The Li‐Mg with about 5 wt. % Mg (abbreviated as Li‐Mg5) has the lowest absorption energy of Li, thus all the surface area can be “controlled” by Mg atoms, leading to the smooth and continuous deposition of Li on the surface around the Mg center. A localized high concentration electrolyte enables Li‐Mg5 to exhibit the best cycling stability in Li metal batteries with high‐loading cathode and lean electrolyte under 4.4 V high‐voltage, which is approaching the demand of practical application. This electrolyte also helps generate an inorganic‐rich solid electrolyte interphase, which leads to smooth, compact and less corrosion layer on the Li‐Mg5 surface. Both theoretical simulations and experimental results prove that Li‐Mg5 has optimum Mg content and gives best battery cycling performance.

Gao, Peiyuan↗
DOE OSTI2021

Optimization of Magnesium-Doped Lithium Metal Anode for High Performance Lithium Metal Batteries through Modeling and Experiment

Lithium (Li)-magnesium (Mg) alloy with limited Mg amount, which can also be called Mg-doped Li (Li-Mg), has been considered as a potential alternative anode for high energy density rechargeable Li metal batteries. However, the optimum doping-content of Mg in Li-Mg anode and the mechanism of the improved performance are not well understood. In this study, density functional theory (DFT) calculations are used to investigate the effect of Mg amount in Li-Mg anode. The Li-Mg with about 5 wt. % Mg (abbreviated as Li-Mg5) has the lowest absorption energy of Li, thus all the surface area can be “controlled” by Mg atoms, leading to the smooth and continuous deposition of Li on the surface around the Mg center. A localized high concentration electrolyte enables Li-Mg5 to exhibit the best cycling stability in Li metal batteries with high-loading cathode and lean electrolyte under 4.4 V high-voltage, which is approaching the demand of practical application. This electrolyte also helps generate an inorganic-rich solid electrolyte interphase, which leads to smooth, compact and less corrosion layer on the Li-Mg5 surface. Both theoretical simulations and experimental results prove that Li-Mg5 has optimum Mg content and gives best battery cycling performance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Interplay of molten salt and dopants in tuning the performance of single-crystalline LiNiO 2

Single-crystalline layered oxide cathodes have seen great research interest in recent years. Adoption of single-crystal morphology improves mechanical robustness and eliminates intergranular boundaries, improving the chemical stability of the cathode. Furthermore, single-crystal cathodes also suffer from worsened lithium-diffusion kinetics stemming from the significantly increased diffusion path lengths. Sluggish lithiation kinetics induce concentration gradients within the cathode particle during cell operation, resulting in the accumulation of lattice strain, which deteriorates cell performance. Foreign dopants have been shown to greatly improve ion diffusion in many high-Ni layered oxide cathode systems. In particular, we identify Ti and Te as promising dopants to ameliorate the slow diffusion kinetics. We find that doping 1 mol.% Te into single crystal LiNiO 2 greatly improves Li + diffusivity, as determined through galvanostatic intermittent titration technique. Further incorporating 2 mol.% Al and pairing with lithium-metal anode in a localized high concentration electrolyte (LHCE) delivers 206 mA h g -1 at C/3 rate and retains 94% capacity after 100 cycles in Li metal half cells. By addressing kinetically mediated degradation with Te doping, and surface-based degradation with Al and LHCE, the cathode experiences very little polarization and overpotential growth, enabling stable cycling with high accessible capacity.

25 ENERGY STORAGE↗
DOE OSTI2020

Lithium Metal Anodes with Nonaqueous Electrolytes

High-energy rechargeable lithium (Li) metal batteries (LMBs) with Li metal anode (LMA) were first developed in the 1970s, but their practical applications have been hindered by the safety and low-efficiency concerns related to LMA. Recently, a worldwide effort on LMA-based rechargeable LMBs has been revived to replace graphite-based, Li-ion batteries because of the much higher energy density that can be achieved with LMBs. Herein, this review focuses on the recent progress on the stabilization of LMA with nonaqueous electrolytes and reveals the fundamental mechanisms behind this improved stability. Various strategies that can enhance the stability of LMA in practical conditions and perspectives on the future development of LMA are also discussed. These strategies include the use of novel electrolytes such as superconcentrated electrolytes, localized high-concentration electrolytes, and highly fluorinated electrolytes, surface coatings that can form a solid electrolyte interphase with a high interfacial energy and self-healing capabilities, development of “anode-free” Li batteries to minimize the interaction between LMA and electrolyte, approaches to enable operation of LMA in practical conditions, etc. Combination of these strategies ultimately will lead us closer to the large-scale application of LMBs which often is called the “Holy Grail” of energy storage systems.

25 ENERGY STORAGE↗
DOE OSTI2023

Improving Cycling Performance of Anode-Free Lithium Batteries by Pressure and Voltage Control

The anode-free lithium (Li) batteries (AFLBs) have great potential to provide higher energy density than most other batteries. However, the performance of AFLBs is very sensitive to pressure and other operating parameters, especially for coin cells widely used in AFLB investigations. Therefore, optimizing cell assembly parameters and test protocol is critical to get reliable and comparable results in this field. In this work, the operating voltage range of AFLBs using a localized high concentration electrolyte has been optimized. The morphology of the deposited Li in AFLBs is much more indicting to the pressure than other type of batteries due to the absence of anode active material (i.e. Li) as a pressure cushion layer in the as prepared cells. With an optimized cycling protocol, a thin layer of uniform nucleation sites can be formed in the initial cycle which will facilitate smooth Li desposition/stripping in the subsequent cycles of AFLBs. The solid electrolyte interphase layer formed under optimized pressure and uniform pressure distribution exhibits a good mechanical stability even after long-term cycling. In conclusion, with an optimized cell configuration, the internal pressure in the coin cells has been optimized to improve the cycling performance of AFLBs (Cu||NMC811) with 72% of capacity retention in 100 cycles.

25 ENERGY STORAGE↗
DOE OSTI2024

Single-phase local-high-concentration solid polymer electrolytes for lithium-metal batteries

Solid polymers are promising electrolytes for Li-metal batteries, but they have limitations: they cannot simultaneously achieve high ionic conductivity, good mechanical strength and compatibility with high-voltage cathodes while suppressing Li dendrites. Here, we design a class of locally high-concentration solid polymer electrolytes based on polymer blends, which are termed Li-polymer in F diluter (LPIFD). The Li-polymer (polymer-in-salt) ensures continuous Li-ion conduction channels and contributes to the solid electrolyte interphase (SEI), and the F diluter (inert fluorinated polymer) adds mechanical strength. Studies reveal that a single-phase LPIFD, which is based on a miscible polymer blend, lacks phase boundaries and forms an organic-less and LiF-rich SEI, effectively suppressing lithium dendrites. The single-phase LPIFD delivers ionic conductivity of 3.0 x 10 -4 S cm -1 and enables the Li anode to reach a high coulombic efficiency of 99.1% and a critical current density of 3.7 mA cm -2 . Furthermore, the ability to form an F-rich cathode electrolyte interphase allows LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cells to achieve a cycle life of 450 cycles at a high operating voltage of 4.5 V. In conclusion, this design will inspire efforts to commercialize polymer electrolytes for high-energy Li-metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Role of inner solvation sheath within salt–solvent complexes in tailoring electrode/electrolyte interphases for lithium metal batteries

Functional electrolyte is the key to stabilizing the highly reductive lithium (Li) metal anode (LMA) and high voltage cathode for long life, high energy-density rechargeable Li metal batteries (LMBs). However, fundamental knowledge of the interaction principles between reactive electrodes and electrolytes is still limited. Recently localized high-concentration electrolytes (LHCEs) are emerging as promising electrolyte design strategies for LMBs. They can also serve as an ideal platform for understanding the reactivity characteristics of the inner solvation sheath on electrode surfaces due to their unique solvation structures. Here, we study the effects of a series of LHCEs with model electrolyte solvents (carbonate, sulfone, phosphate and ether) in high voltage LMBs. Varied electrode stabilities exhibited in different LHCEs indicate the intricate synergies between the salt and the solvent on electrode surfaces. Experimental and theoretical analyses reveal an intriguing general rule that the strong interactions between the salt and the solvent in the inner solvation sheath promote their intermolecular proton/charge transfer reactions, which dictates the properties of the electrode/electrolyte interphases and thus the battery performances.

Solvation sheath, salt-solvent complex, electrode/↗
DOE OSTI2026

Electrolyte Design for Fast‐Charging Lithium‐Based Batteries

Fast charging is essential for the widespread adoption of lithium (Li)-ion batteries, but it is fundamentally limited by sluggish interfacial kinetics, Li plating, and electrolyte instability at high current densities. Over the past decade, electrolyte engineering has emerged as a key strategy to address these challenges. This review summarizes the development of fast-charging electrolytes over the past ten years and outlines a design framework. Electrolyte formulations are first deconstructed into their main components—solvents, salts, and functional additives—and representative strategies for tuning solvation structure and interphase chemistry are discussed to suppress Li plating and improve interfacial kinetics. The discussion then extends to advanced electrolyte systems, particularly localized high-concentration electrolytes (LHCEs), and their compatibility with different anode chemistries. Advanced characterization techniques are also summarized and categorized based on destructiveness, spatial and temporal resolution, quantitative analysis, and the chemical species or processes probed across multiple length scales. Recent progress in AI-enabled electrolyte discovery and battery management system (BMS) strategies for optimized fast-charging protocols is further highlighted. Finally, perspectives are presented on translating electrolyte innovations from academic research to practical applications, with emphasis on cell format, realistic operating conditions, and manufacturability.

25 ENERGY STORAGE↗
DOE OSTI2022

Room-Temperature Pseudo-Solid-State Iron Fluoride Conversion Battery with High Ionic Conductivity

Li-metal batteries (LMBs) employing conversion cathode materials (e.g., FeF 3 ) are a promising way to prepare inexpensive, environmentally friendly batteries with high energy density. Pseudo-solid-state ionogel separators harness the energy density and safety advantages of solid-state LMBs, while alleviating key drawbacks (e.g., poor ionic conductivity and high interfacial resistance). In this work, a pseudo-solid-state conversion battery (Li-FeF 3 ) is presented that achieves stable, high rate (1.0 mA cm –2 ) cycling at room temperature. The batteries described herein contain gel-infiltrated FeF 3 cathodes prepared by exchanging the ionic liquid in a polymer ionogel with a localized high-concentration electrolyte (LHCE). The LHCE gel merges the benefits of a flexible separator (e.g., adaptation to conversion-related volume changes) with the excellent chemical stability and high ionic conductivity (~2 mS cm –1 at 25 °C) of an LHCE. The latter property is in contrast to previous solid-state iron fluoride batteries, where poor ionic conductivities necessitated elevated temperatures to realize practical power levels. Importantly, the stable, room-temperature Li-FeF 3 cycling performance obtained with the LHCE gel at high current densities paves the way for exploring a range of architectures including flexible, three-dimensional, and custom shape batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Facile Dual-Protection Layer and Advanced Electrolyte Enhancing Performances of Cobalt-free/Nickel-rich Cathodes in Lithium-Ion Batteries

Despite cobalt (Co)-free/nickel (Ni)-rich layered oxides being considered as one of the promising cathode materials due to their high specific capacity, their highly reactive surface is one of the shortcomings that still hinder their practical usages in high-energy-density batteries. Herein, a polyimide/polyvinylpyrrolidone (PI/PVP, denoted as PP) coating layer is demonstrated as dual-protection for LiNi 0.96 Mg 0.02 Ti 0.02 O 2 (NMT) cathode material to suppress surface contamination against moisty air and to prevent unwanted side reactions between cathode and electrolyte during electrochemical cycling. The optimal PP-coated NMT (PP@NMT) preserves a clean surface without generation of lithium (Li) residues, structural degradation, and gas evolution after exposure to air with ~30% humidity for 2 weeks. Contrarily, the exposed bare NMT shows severe contamination, structural shrinkage due to Li loss, and increased gas release during charging. In addition, the exposed PP@NMT significantly enhances the electrochemical performance of graphite (Gr)||NMT cells by decreasing byproducts and maintaining structural stability. Moreover, the exposed PP@NMT achieves a high capacity retention of 86.7% after 500 cycles in Gr||NMT cells using an advanced localized high-concentration electrolyte. Furthermore, this work demonstrates a promising facile approach to the protection of Co-free/Ni-rich layered cathodes for their practical applications even after exposure to moisty air.

25 ENERGY STORAGE↗
DOE OSTI2023

Demarcating the Impact of Electrolytes on High–Nickel Cathodes and Lithium–Metal Anode

The ever-growing demand for low-cost, high-energy-density lithium-ion batteries (LIBs) makes high-nickel layered oxide cathodes, especially LiNiO 2 (LNO), one of the most appealing candidates. However, poor structural and surface instability that leads to a short cycle life remains a formidable challenge. Herein, a systematic investigation of LNO performance in two different electrolytes (a conventional carbonate-based LP57 electrolyte and an ether-based localized high-concentration electrolyte (LHCE)) with different charge cut-off voltages is presented. These findings show that the cathode-electrolyte reactivity is the main factor dictating the performance degradation of LNO at high voltages rather than bulk integrity. While LHCE can provide good stability beyond 4.2 V with a robust, uniform solid–electrolyte interphase (SEI) layer on the Li-metal anode, there is no significant difference in cyclability at 4.15 V (96% capacity retention after 200 cycles) for both LP57 and LHCE. From LNO symmetric cells, carbonate-based electrolyte is found to be good for LNO stability while ether-based electrolyte is beneficial toward Li-metal anode. Furthermore, a suitable electrolyte or a low cut-off voltage is necessary to maintain a decent cycle life. Altogether, this work highlights the impact of electrolyte and cut-off voltage on LNO and Li-metal, which can help guide the development of cells based on LNO.

25 ENERGY STORAGE↗
DOE OSTI2025

Locally Confined Polysulfide-Reactive Electrolytes for Shuttle-Free Sodium–Sulfur Batteries

Sodium-sulfur batteries promise high-energy-density and sustainable electrochemical energy storage but suffer from uncontrolled polysulfides dissolution and high sodium reactivity. These challenges fundamentally originate from poor electrolyte-electrode compatibility. Current electrolyte research inadequately addresses the trade-off between minimal polysulfides solvation and stabilizing sodium interfaces. Here, we present a locally-confined polysulfide-reactive electrolyte strategy that mediates the polysulfide dissolution dynamics and sodium stability by leveraging an electrophilic solvating species with a localized high-concentration electrolyte. This design enables shuttle-free cell operation by synergistically restricting the global solvating power of the electrolyte through intermolecular interactions and locally scavenging sparingly dissolved polysulfides via electrolyte electrophilicity. The precisely confined surface reaction facilitates a protective cathode-electrolyte interface, realizing a quasi-solid-state sulfur conversion in our liquid ether-based electrolyte, which crucially avoids crossover-induced catastrophic sodium-metal degradation. The proposed electrolyte demonstrates long-term cycling of high-mass-loading sulfur cathodes (> 3 mg S cm −2 with commercial carbon host and 70 wt% sulfur content), which afford 710 mA h g −1 over 400 cycles in coin cells and steady pouch cell operation over 180 cycles. Furthermore, this work establishes a scalable electrolyte design protocol that regulates the reaction chemistry of highly reactive electrodes, offering a pathway toward sustainable renewable energy storage.

25 ENERGY STORAGE↗
DOE OSTI2022

Is Nonflammability of Electrolyte Overrated in the Overall Safety Performance of Lithium Ion Batteries? A Sobering Revelation from a Completely Nonflammable Electrolyte

It has been widely assumed that the flammability of the liquid electrolyte is one of the most influential factors that determine the safety of lithium-ion batteries (LIBs). Following this consideration, a completely nonflammable electrolyte is designed and adopted for graphite||LiFePO 4 (Gr||LFP) batteries. Contrary to the conventional understanding, the completely nonflammable electrolyte with phosphorus-containing solvents exhibits inferior safety performance in commercial Gr||LFP batteries, in comparison to the flammable conventional LiPF 6 -organocarbonate electrolyte. Mechanistic studies identify the exothermic reactions between the electrolyte (especially the salt LiFSI) and the charged electrodes as the “culprit” behind this counterintuitive phenomenon. The discovery emphasizes the importance of reducing the electrolyte reactivity when designing safe electrolytes, as well as the necessity of evaluating safety performance of electrolytes on a battery level.

25 ENERGY STORAGE↗
DOE OSTI2023

Interfacial pressure improves calendar aging of lithium metal anodes

Lithium (Li) metal is a promising anode because its theoretical specific capacity is approximately ten times larger than graphite. However, Li anodes suffer from long-term capacity fade due to Li stranding (becoming electronically disconnected) and electrolyte decomposition. Applied interfacial pressure has been shown to improve Li anode cycling, likely due to reincorporating stranded or “dead” Li into the anode. Calendar aging can also lead to Li capacity loss due to electrolyte decomposition/Li corrosion and the formation of stranded Li. Some research suggests that calendar aging during cycling results in reversible capacity losses due to Li stranding and reconnection. We here investigate the effect of applied interfacial pressure on Li anode calendar aging during cycling with incorporated rest steps in a localized high-concentration electrolyte (LHCE) to understand if pressure can mitigate stranded Li formation during rest by manipulating the Li morphology. Pouch cells exhibit more stable cycling and denser Li deposits between 10 kPa and 1,000 kPa of applied pressure compared to no applied pressure. Despite drops in CE during periodic rest cycles, the average cumulative lost capacity and average coulombic efficiency (CE) of cells over 50 cycles show that cells aged with incorporated rest steps perform similarly to cells cycled without added rests. This similar average CE suggests that dead Li is largely responsible for drops in CE during rest rather than irreversible Li corrosion and that the dead Li can be reconnected in subsequent cycling. The addition of a lithiophilic ZnO coating to the Cu working electrode increases the adhesion and coverage of Li deposits at low pressures and improves CE during the first cycle.

25 ENERGY STORAGE↗
DOE OSTI2025

Rational Electrolyte Design for Elevated-Temperature and Thermally Stable Lithium-Ion Batteries with Nickel-Rich Cathodes

As the energy density of lithium-ion batteries (LIBs) increases, the shortened cycle life and the increased safety hazard of LIBs are drawing increasing concerns. To address such challenges, a series of localized high-concentration electrolytes (LHCEs) based on a solvating-solvent mixture of tetramethylene sulfone and trimethyl phosphate and a high flash-point diluent 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether were designed. The LHCEs exhibited non-flammability and greatly suppressed heat release at high temperatures, which would potentially improve the safety performance of the LIBs. Moreover, the optimal LHCE achieved capacity retentions of 87.1% and 81.7% in graphite||LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells after 500 cycles at 25 °C and 45 °C, respectively, which were significantly better than the conventional electrolyte, whose capacity retentions were only 75.2% and 38.5% under the same condition. Mechanistic studies revealed that the LHCE not only formed a more robust solid electrolyte interphase, but also exhibited improved anodic stability, compared with the conventional electrolyte. Further, this work sheds light in rational electrolyte design for high energy density LIBs with high battery performance and low safety concerns.

25 ENERGY STORAGE↗
DOE OSTI2025

Advanced All-Fluorinated Electrolytes for Extended Cycle Life and Stability of Li||SPAN Batteries

Achieving long-term stability and consistent capacity in lithium (Li) metal batteries with sulfurized polyacrylonitrile (SPAN) cathodes requires precisely engineered electrolytes to optimize interphase formation and redox reversibility. Here, this study presents 1,1-difluoro-2-(2-methoxyethoxy)ethane (DFE)-based localized high-concentration electrolytes (LHCEs), incorporating fluorinated components such as salt, solvating solvent, and diluent for improved electrode stability. Molecular dynamics simulations and surface analyses reveal that the DFE-LHCE with 1,2-bis(1,1,2,2-tetrafluoroethoxy)ethane (BTFEE) diluent produces uniform and robust interphase layers on both cathode and anode, enriched with inorganic species like LiF and Li 2 O. These properties lead to prolonged redox reversibility of the SPAN cathode, suppressed side reactions, and extended cycle life for Li||SPAN cells. Remarkably, DFE-BTFEE-LHCE enables Li||SPAN coin cells with an areal capacity of ∼7 mAh cm -2 for SPAN to retain 81.3% capacity after 200 cycles and pouch cells of 0.12 Ah with 8 mAh cm -2 of SPAN and lean electrolyte to maintain 96.4% capacity over 80 cycles. These findings pave the way for advancing Li||SPAN battery technologies.

25 ENERGY STORAGE↗