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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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Removal of Surface Carbonate from Lithium-Ion Battery Cathode Materials via Vapor-Phase Fluorination

Herein, ultrathin metal-fluoride barrier coatings on the surface of lithium-ion battery (LIB) cathodes can improve cycling stability and prevent corrosion by acidic byproducts in the electrolyte. Atomic layer deposition (ALD) is an effective method to deposit ultrathin metal fluoride coatings on LIB cathodes. Although numerous studies have demonstrated the benefit of ALD metal fluoride coatings to LIB performance, comparatively few works have examined the effect of individual ALD precursors on the cathode surface. This paper uses X-ray photoelectron spectroscopy (XPS) measurements to elucidate the surface chemical changes on LIB cathode material surfaces upon exposure to the ALD metal fluoride precursor, hydrogen fluorine pyridine (HFPy). We found a decrease in surface carbonate and an increase in surface fluoride after HFPy exposure suggesting the conversion of lithium carbonate (Li 2 CO 3 ) to lithium fluoride (LiF). This conversion is desirable given that Li 2 CO 3 degrades LIB performance, whereas LiF provides an excellent physio-chemical barrier against chemical attack during cycling. Scanning transmission electron microscopy, X-ray energy dispersive spectroscopy, and XPS measurements following HFPy exposure to Li 2 CO 3 powder revealed the formation of a conformal LiF shell around the Li 2 CO 3 particles. Finally, we confirmed the complete conversion of similar to 7 nm ALD Li 2 CO 3 films on silicon from HFPy exposure using XPS and spectroscopic ellipsometry. The elimination of problematic Li 2 CO 3 from LIB cathode surfaces and conversion into a protective LiF coating via a single precursor vapor treatment may provide a cost-effective method for enhancing LIB performance.

25 ENERGY STORAGE↗
DOE OSTI2020

Stabilizing and understanding the interface between nickel-rich cathode and PEO-based electrolyte by lithium niobium oxide coating for high-performance all-solid-state batteries

The pursuit of high energy density and safe lithium ion batteries (LIBs) is the urgent goal for the development of next-generation electric vehicles (EVs). All-solid-state batteries (ASSBs) with the combination of poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE) and Ni-rich lithium nickel manganese cobalt oxide LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode are promising candidates for EVs due to their improved energy density and safety. However, the low electrochemical oxidation window of PEO-based SPE and the instability of NMC811 at the charge/discharge process seriously restrict the battery performance. Herein, a high voltage stable solid-state electrolyte layer lithium niobium oxide (LNO) is coated on the NMC811 electrode surface by atomic layer deposition for stabilizing NMC811-PEO solid polymer batteries. Electrochemical tests show that LNO coating can stabilize the NMC811 active materials and mitigate the decomposition of SPE upon the cycling process, rendering a good performance of NMC811-PEO solid polymer battery. Mechanism studies by SEM, STEM, XAS, and XPS disclose that the uncoated NMC811 suffers from chemomechanical degradations along with oxygen release triggering the decomposition of SPE, which results in unstable cathodic electrolyte interphase. With LNO coating, chemomechanical degradations and oxygen release are inhibited and the decomposition of SPE is mitigated. This paper renders a stable and high-performance high-energy-density SSB for high voltage application, which paves the way toward next-generation solid-state LIBs.

25 ENERGY STORAGE↗
DOE OSTI2023

Modifying Surface Chemistry to Enhance the Electrochemical Stability of Nickel‐Rich Cathode Materials

Residual impurities such as lithium carbonate and hydroxide are a major concern for accelerating parasitic reactions at the cathode electrolyte interface of lithium-ion batteries. Removal of these lithium-bearing species becomes a necessity for high-performance nickel-rich cathode materials. Instead of directly removing these impurities through washing steps, a wet impregnation process is employed to convert these detrimental surface impurities into beneficial surface coating on nickel-rich cathode materials. Specifically, the pristine cathode material is treated with Al(H 2 PO 4 ) 3 solution to convert undesired compounds into Li 3 PO 4 and AlPO 4 , both of which are considered positive surface coating materials for high-voltage cathodes. It is found that the introduced modification greatly suppresses the interfacial impedance hike and improves the capacity retention of the cathode material after repeating charging/discharging. It is believed that these benefits are realized through the modification of the surface chemistry of the cathode material, which helps to slow down the parasitic reactions and reduce the damage to the cathode material.

25 ENERGY STORAGE↗
DOE OSTI2025

Cold-Sprayed NMC622 Composite as a Cathode for Lithium-Ion Batteries

The growing demand for high-energy, low-cost lithium-ion batteries (LIBs) to power electric vehicles (EVs) necessitates advances in both materials and manufacturing processes. Conventional cathode fabrication methods, such as slurry casting and drying, are energy-intensive and pose challenges for scalability and environmental compliance. In this study, we propose cold-spray (CS) deposition as a solvent-free approach for fabricating LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) composite cathodes. Powder blends of NMC622, poly(vinylidene fluoride) (PVDF), and carbon black (CB) are directly deposited onto stainless steel and Inconel substrates under varied gas temperatures, pressures (and thus velocities), and standoff distances. The effects of temperature on the deposit morphology, coating density, and volume are systematically investigated. Computational fluid dynamics simulations reveal that increasing the gas temperature enhances the particle velocity, narrows the spray angle, and reduces the mass concentration radially at the nozzle outlet. CS deposition results in a dense cathode microstructure, accompanied by fracture in polycrystalline NMC622 particles. X-ray diffraction analysis further verifies that there are no phase changes during the deposition process. The electrochemical performance of the cold-sprayed cathodes reveals an initial capacity of approximately 96 mAh g –1 for single-crystal NMC622 and 167 mAh g –1 for polycrystalline NMC622. While these values are modest compared to state-of-the-art slurry-cast cathodes, which typically exhibit 180–200 mAh g –1 under optimized conditions. The results demonstrate a competitive performance given the solvent-free nature of the CS process and compare favorably with tape-cast samples made from identical feedstock. In conclusion, he CS process enables the formation of dense, binder-integrated cathode coatings without the need for solvent processing, offering a promising pathway for scalable, energy-efficient dry electrode manufacturing of next-generation LIBs.

Batteries↗
DOE OSTI2025

Assessing the coating implications of slurry formulations in NCMA and LFMP blend cathodes for lithium-ion batteries

This paper investigates the implications of slurry formulations and electrode processing on the performance of lithium-ion battery (LIB) cathodes, focusing on Nickel Cobalt Manganese Aluminum (NCMA) and Lithium Ferro Manganese Phosphate (LFMP) blends. Through a comprehensive examination of electrode processing steps, from material selection to coating application, we elucidate the critical role of processing parameters in shaping electrode morphology and electrochemical behavior. Rheological studies reveal the influence of slurry composition on viscosity and flow behavior, highlighting the importance of achieving optimal rheological properties for uniform coating deposition. Electrochemical characterization, including cyclic voltammetry and rate capability tests, unveils the electrochemical behavior of NCMA, LFMP, and their blend, showcasing the synergistic effects of material blending on battery performance. In conclusion, our findings underscore the intricate relationship between slurry formulation, electrode processing, and LIB performance, offering valuable insights for the design and optimization of high-performance electrode materials for next-generation batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Carbon dioxide treatment of cathodes

A method for producing water resistant cathodes is discussed. The method uses mixing cathode powder with solid carbon dioxide to create a mixture and heating the mixture to a temperature. The heating occurs for a time sufficient to cause lithium carbonate coatings to form on the powder. A method for coating lithium-containing cathode surfaces is also discussed. This method uses simultaneously sublimating solid CO 2 and condensing atmospheric water vapor onto surfaces. Afterwards allowing the lithium to react with the sublimated CO 2 for a time sufficient to create a lithium carbonate film on the surface.

Kahvecioglu, Ozgenur↗
DOE OSTI2022

The Electrochemical Behavior of As-Prepared Aluminum Alloy A360 Produced by Selective Laser Melting Fabrication with and without a Trivalent Chromium Process Conversion Coating

In this paper, we report on the electrochemical behavior and corrosion resistance of as-prepared aluminum alloy, A360 (AlSi10Mg), fabricated by additive manufacturing, with and without a trivalent chromium process conversion coating. Selective laser melting was the 3D printing process used for the alloy build. The corrosion suppression provided by the coating system was assessed through electrochemical measurements and accelerated degradation testing during a 14-day continuous neutral salt-spray exposure. The results indicate that the conversion coating can be formed by solution pretreating (degreasing and deoxidation) the alloy (X-Z plane perpendicular to the build plane) with its native surface roughness (as-prepared) followed by immersion for 10, 15 or 20 min in the coating bath. All three immersion times provide an equivalent level of corrosion protection to the alloy. The conversion coating suppresses both anodic and cathodic currents, increases the polarization resistance, and provides both anodic and cathodic corrosion protection to the as-prepared alloy. The conversion-coated specimens exhibit good stand-alone corrosion resistance during a 14-day neutral salt-spray exposure with corrosion intensity values (g/m 2 -year) ~10x lower than values for the uncoated, as-prepared alloy specimens.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Solvent-Free and Non-Sintered 500 Wh/kg All Solid-State Battery

Navitas teamed up with UMD and ORNL to establish a reliable scientific research team. The project addressed processing limitations of state-of-the-art solid electrolytes by extending solvent-free electrode fabrication technology to the scalable production of cathode/solid electrolyte laminates. The innovation started with a solid-state sulfide electrolyte (LiPS) with Cl stabilization able to meet the keystone conductivity challenge in a film of practical thickness (μ 50 µm). The electrolyte was based on a composite of PTFE, and stabilized LiPSCl. With optimization, the ionic conductivity reached 3.3 ×10 -3 S/cm. The solid electrolyte with as low as 0.4% binder allowed long term cycling (> 500 cycles) of Li/SSE/Li cell at > 4 mA/cm 2 with the utilization of Li > 80%. The Li and SSE interfaces were successfully protected with LiF-rich SEI layer. NCM811cathode active materials were coated with a thin layer of Al 2 O 3 (5 nm). The free standing cathode film was fabricated through dry-process with Al2O3-coated NCM811, LiPSCl, active carbon, and small amount PTFE. The all-solid-state batteries were laminated with free standing surface coated NCM811 cathode film, free standing LiPSCl SSE film, and surface protected Li anode together in a single lamination step, and demonstrated high specific capacity (> 200 mAh/g) with coulombic efficiency > 99.5%. The all-solid-state batteries through solvent-free and no-sintering process are promising for large format cell with 500 Wh/Kg specific energy density.

25 ENERGY STORAGE↗
DOE OSTI2020

Enabling Stable Cycling of 4.2 V High-Voltage All-Solid-State Batteries with PEO-Based Solid Electrolyte

Poly(ethylene oxide) (PEO)-based solid electrolytes are expected to be exploited in solid-state batteries with high safety. Its narrow electrochemical window, however, limits the potential for high voltage and high energy density applications. In this paper, the electrochemical oxidation behavior of PEO and the failure mechanisms of LiCoO 2 -PEO solid-state batteries are studied. It is found that although for pure PEO it starts to oxidize at a voltage of above 3.9 V versus Li/Li + , the decomposition products have appropriate Li + conductivity that unexpectedly form a relatively stable cathode electrolyte interphase (CEI) layer at the PEO and electrode interface. The performance degradation of the LiCoO 2 -PEO battery originates from the strong oxidizing ability of LiCoO 2 after delithiation at high voltages, which accelerates the decomposition of PEO and drives the self-oxygen-release of LiCoO 2 , leading to the unceasing growth of CEI and the destruction of the LiCoO 2 surface. When LiCoO 2 is well coated or a stable cathode LiMn 0.7 Fe 0.3 PO 4 is used, a substantially improved electrochemical performance can be achieved, with 88.6% capacity retention after 50 cycles for Li 1.4 Al 0.4 Ti 1.6 (PO 4 ) 3 coated LiCoO 2 and 90.3% capacity retention after 100 cycles for LiMn 0.7 Fe 0.3 PO 4 . The results suggest that, when paired with stable cathodes, the PEO-based solid polymer electrolytes could be compatible with high voltage operation.

25 ENERGY STORAGE↗
DOE OSTI2025

Impacts of the Conductive Networks on Solid‐State Battery Operation

The micromorphology of composite cathodes is known to play a vital role in determining all-solid-state battery (ASSB) performance. However, much of our current understanding is derived from empirical observations, lacking a deeper mechanistic foundation. The “rocking chair” concept of battery chemistry requires maintaining charge neutrality, emphasizing the necessity of examining electrode micromorphology from the perspective of conductive networks. This study systematically investigates the microscopic electrochemical impacts of conductive network micromorphology by varying the Li + -to-e − channel ratio in cathodes comprising LiNbO 3 -coated LiNi 0.8 Co 0.1 Mn 0.1 O 2 , Li 6 PS 5 Cl, and carbon fibers. Utilizing multiscale synchrotron-based spectro-microscopy, we unravel that unbalanced Li + and e − conducting channels intensify charge polarization within active cathode particles and accelerate their degradation. A further model system with X-ray nano-tomography resolved e − and Li + channels indicates that spatially uniform and well-paired Li + and e − conducting channels are highly desirable as they could promote more uniform lithiation/delithiation, mitigating microscopic electrochemical polarization. Electrode-scale X-ray holotomography analysis reveals that the impact of conductive networks is particle-size-dependent, with smaller cathode particles being more significantly affected. These findings provide mechanistic insights into the interplay between conductive networks and all-solid-state battery operation, laying the groundwork for rational design and optimization of cathode architectures in future solid-state battery technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Atomic-scale constituting stable interface for improved LiNi 0.6 Mn 0.2 Co 0.2 O 2 cathodes of lithium-ion batteries

Ascribed to their higher capacity and lower cost compared to conventional LiCoO 2 , the Ni-rich layered LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) is now considered as one promising cathode for lithium-ion batteries (LIBs). However, it still suffers from some evident performance degradation, especially under high cutoff voltages (i.e., >4.3 V versus Li/Li + ). The performance degradation typically is exhibited as capacity fading and voltage drop, mainly originating from an instable interface between the NMC622 and electrolyte as well as the evolution of the NMC structure. To improve the interfacial and structural stability of NMC cathodes, herein we deposited an ultrathin layer of Al 2 O 3 coatings (<5 nm) conformally over NMC622 composite electrodes directly using atomic layer deposition (ALD). It was found that, under different upper cutoff voltages (4.3, 4.5, and 4.7 V), the ALD Al 2 O 3 coatings enable enhanced performance of NMC622 cathodes with better cyclability and higher capacity. Particularly, the beneficial effects of the ALD Al 2 O 3 coatings are more remarkable at higher upper cutoff voltages (4.5 and 4.7 V). Furthermore, the ALD coatings can significantly improve the rate capability of NMC622. To this end, we utilized a suite of characterization tools and performed a series of electrochemical tests to clarify the effects of the ALD Al 2 O 3 coatings. This study revealed that the beneficial effects of the Al 2 O 3 ALD coatings are multiple: (i) serving as an artificial layer of solid electrolyte interphase to mitigate undesirable interfacial reactions; (ii) acting as a physical barrier to inhibit metal dissolution of NMC; and (iii) forming a reinforced networked overcoating to boost the mechanical integrity of NMC cathodes. This study is favorable for designing high-performance NMC cathodes.

25 ENERGY STORAGE↗
DOE OSTI2025

Interphase Engineering Enabled by Using a Separator with Electrochemically Active Carbazole Polymers for Lithium-Ion Batteries

Separators are generally considered inert components in lithium-ion batteries. In the past, some electroactive polymers have been successfully applied in separator modifications for overcharge protection or as acid scavengers. This study highlights the first use of two “electroactive” carbazole polymers (copolymer 9-phenyl-9H-carbazole-phenyl [PCP] and poly(9-vinylcarbazole) [PVC]), which were each applied separately as coatings on the cathode-facing side of commercial Celgard 2325 separators, respectively, to enhance the cycling performance of 0.3Li 2 MnO 3 ·0.7LiMn 0.5 Ni 0.5 O 2 //graphite (LMR-NM//Gr) full cells through interphase engineering. The team observed an irreversible polymer oxidation process of the carbazole-functionalized polymers—occurring only during the first charge—for the modified separator cells, and the results were confirmed by dQ/dV analysis, cyclic voltammetry measurements, and nuclear magnetic resonance characterizations. During this oxidation, carbazole polymers participate in the process of interphase formation, contributing to the improved cycling performance of LMR-NM//Gr batteries. Particularly, oxidation takes place at voltages of ~4.0 and ~3.5 V when PCP and PVC are used as separator coatings, which is highly irreversible. Further postmortem examinations suggest that the improvements using these modified separators arise from the formation of higher-quality and more inorganic SEI, as well as the beneficial CEI enriched in LixPOyFz. These interphases effectively inhibit the crosstalk effect by reducing TM dissolution.

carbazole↗
DOE OSTI2022

Atomic layer deposition of lithium zirconium oxides for the improved performance of lithium-ion batteries

Recently there has been increasing interest to develop lithium-containing films as solid-state electrolytes or surface coatings for lithium-ion batteries (LIBs) and related systems. Here, in this study, we for the first time investigated the thin film growth of lithium zirconium oxides (Li x Zr y O or LZOs) through combining two individual atomic layer deposition (ALD) processes of ZrO 2 and LiOH, i.e., sub-ALD of ZrO 2 and LiOH. We revealed that the hygroscopic nature of the LiOH component has a big impact on the growth of LZOs. We found that an increased temperature to 225 °C was more effective than an elongated purge to mitigate the adverse effects of physisorbed H 2 O. We further discovered that, during the resultant LZO super-ALD processes, the growth of sub-ALD LiOH has been promoted while the growth of sub-ALD ZrO 2 has been inhibited. In this study, a suite of instruments has been applied to characterize the LZO super-ALD processes and the resultant LZO films, including in situ quartz crystal microbalance (QCM), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM), synchrotron-based X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Furthermore, we applied the resulting LZO films over LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) cathodes in LIBs and demonstrated that the LZO coating films could evidently improve the lithium-ion insertion and extraction rates of the NMC622 electrodes up to 3.4 and 2.6 times, respectively. The LZO-coated NMC622 cathodes exhibited much better performance than the uncoated NMC622 ones.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Transferring Liquid Metal to form a Hybrid Solid Electrolyte via a Wettability-Tuning Technology for Lithium-Metal Anodes

Integrating solid-state electrolyte (SSE) into Li-metal anodes has demonstrated great promise to unleash the high energy density of rechargeable Li-metal batteries. However, fabricating a highly cyclable SSE/Li-metal anode remains a major challenge because the densification of the SSE is usually incompatible with the reactive Li metal. Here, a liquid-metal-derived hybrid solid electrolyte (HSE) is proposed, and a facile transfer technology to construct an artificial HSE on the Li metal is reported. By tuning the wettability of the transfer substrates, electron- and ion-conductive liquid metal is sandwiched between electron-insulating and ion-conductive LiF and oxides to form the HSE. The transfer technology renders the HSE continuous, dense, and uniform. The HSE, having high ion transport, electron shut-off, and mechanical strength, makes the composite anode deliver excellent cyclability for over 4000 h at 0.5 mA cm(-2) and 1 mAh cm(-2) in a symmetrical cell. When pairing with LiFePO4 and sulfur cathodes, the HSE-coated Li metal dramatically enhances the performance of full cells. Therefore, this work demonstrates that tuning the interfacial wetting properties provides an alternate approach to build a robust solid electrolyte, which enables highly efficient Li-metal anodes.

li-metal anodes↗
DOE OSTI2022

Solvent-Free Manufacturing of Lithium-Ion Battery Electrodes via Cold Plasma

Slurry casting has been used to fabricate lithium-ion battery electrodes for decades, which involves toxic and expensive organic solvents followed by high-cost vacuum drying and electrode calendering. This work presents a new manufacturing method using a nonthermal plasma to create inter-particle binding without using any polymeric binding materials, enabling solvent-free manufacturing electrodes with any electrochemistry of choice. The cold-plasma-coating technique enables fabricating electrodes with thickness (>200 μm), high mass loading (>30 mg cm -2 ), high peel strength, and the ability to print lithium-ion batteries in an arbitrary geometry. This crosscutting, chemistry agnostic, platform technology would increase energy density, eliminate the use of solvents, vacuum drying, and calendering processes during production, and reduce manufacturing cost for current and future cell designs. Here, lithium iron phosphate and lithium cobalt oxide were used as examples to demonstrate the efficacy of the cold-plasma-coating technique. It is found that the mechanical peel strength of cold-plasma-coating-manufactured lithium iron phosphate is over an order of magnitude higher than that of slurry-casted lithium iron phosphate electrodes. Full cells assembled with a graphite anode and the cold-plasma-coating-lithium iron phosphate cathode offer highly reversible cycling performance with a capacity retention of 81.6% over 500 cycles. For the highly conductive cathode material lithium cobalt oxide, an areal capacity of 4.2 mAh cm -2 at 0.2 C is attained. We anticipate that this new, highly scalable manufacturing technique will redefine global lithium-ion battery manufacturing providing significantly reduced plant footprints and material costs.

25 ENERGY STORAGE↗