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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 811 records · Page 45
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Ambient‐Pressure Relithiation of Degraded Li x Ni 0.5 Co 0.2 Mn 0.3 O 2 (0 < x < 1) via Eutectic Solutions for Direct Regeneration of Lithium‐Ion Battery Cathodes

Abstract With the rapid growth of the lithium‐ion battery (LIBs) market, recycling and re‐use of end‐of‐life LIBs to reclaim lithium (Li) and transition metal (TM) resources (e.g., Co, Ni), as well as eliminating pollution from disposal of waste batteries, has become an urgent task. Here, for the first time the ambient‐pressure relithiation of degraded LiNi 0.5 Co 0.2 Mn 0.3 O 2 (NCM523) cathodes via eutectic Li + molten‐salt solutions is successfully demonstrated. Combining such a low‐temperature relithiation process with a well‐designed thermal annealing step, NCM523 cathode particles with significant Li loss (≈40%) and capacity degradation (≈50%) can be successfully regenerated to achieve their original composition and crystal structures, leading to effective recovery of their capacity, cycling stability, and rate capability to the levels of the pristine materials. Advanced characterization tools including atomic resolution electron microscopy imaging and electron energy loss spectroscopy are combined to demonstrate that NCM523's original layered crystal structure is recovered. For the first time, it is shown that layer‐to‐rock salt phase change on the surfaces and subsurfaces of the cathode materials can be reversed if lithium can be incorporated back to the material. The result suggests the great promise of using eutectic Li + molten–salt solutions for ambient‐pressure relithiation to recycle and remanufacture degraded LIB cathode materials.

Shi, Yang↗
DOE OSTI2022

Avoiding CO 2 Improves Thermal Stability at the Interface of Li 7 La 3 Zr 2 O 12 Electrolyte with Layered Oxide Cathodes

Abstract Solid‐state batteries promise higher energy densities and better safety than Li‐ion batteries with liquid electrolytes. However, the interface between solid electrolyte and cathode is unstable at the elevated temperatures that are needed while sintering to achieve good bonding between ceramic components. Here, the hypothesis is that, the gas environment, especially the presence of CO 2, is critical in determining the stability of the solid electrolyte–cathode interface. The effect of gas species on the interface is systematically probed, by a using Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte with a thin film LiNi 0.6 Mn 0.2 Co 0.2 O 2 cathode as a model system to enable interface sensitivity. Detrimental phases formed at the interface and their onset conditions are identified by X‐ray absorption spectroscopy, X‐ray diffraction, and Gibbs free energy analysis. As a result, removing CO 2 and minimizing H 2 O(g) during sintering is necessary to obtain good contact at the LLZO|cathode interface without forming secondary phases. Sintering in O 2 is ideal, yielding excellent chemical stability and low interfacial resistance. Secondary phases also do not form in N 2, but oxygen loss occurs at elevated temperatures. The interfacial resistance obtained upon sintering in pure O 2 is comparable to the lowest values at LLZO interfaces with protective coatings, but here without the need for interface coatings.

25 ENERGY STORAGE↗
DOE OSTI2021

Revisiting Discharge Mechanism of CF x as a High Energy Density Cathode Material for Lithium Primary Battery

Lithium/fluorinated graphite (Li/CFx) primary batteries show great promise for applications in a wide range of energy storage systems due to their high energy density (>2100 Wh kg –1 ) and low self-discharge rate (<0.5% per year at 25 °C). While the electrochemical performance of the CF x cathode is indeed promising, the discharge reaction mechanism is not thoroughly understood to date. In this article, a multiscale investigation of the CF x discharge mechanism is performed using a novel cathode structure to minimize the carbon and fluorine additives for precise cathode characterizations. Titration gas chromatography, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, cross-sectional focused ion beam, high-resolution transmission electron microscopy, and scanning transmission electron microscopy with electron energy loss spectroscopy are utilized to investigate this system. Results show no metallic lithium deposition or intercalation during the discharge reaction. Crystalline lithium fluoride particles uniformly distributed with <10 nm sizes into the CF x layers, and carbon with lower sp2 content similar to the hard-carbon structure are the products during discharge. This article deepens the understanding of CF x as a high energy density cathode material and highlights the need for future investigations on primary battery materials to advance performance.

25 ENERGY STORAGE↗
DOE OSTI2022

Scalable Direct Recycling of Cathode Black Mass from Spent Lithium‐Ion Batteries

Abstract End of life (EoL) lithium‐ion batteries (LIBs) are piling up at an intimidating rate, which is alarming for environmental health. With further expected rapid growth of LIB use, the magnitude of spent battery accumulation is also expected to grow. LiNi x Co y Mn z O 2 (NCM) cathode materials are a dominant chemistry in high energy LIBs, and make up a huge portion of this waste accumulation. Direct recycling is one of the most promising ways to turn this waste to wealth, but has been limited to lab‐scale, due to lack of robustness, namely the tedious pretreatment required that involves toxic organic solvents. Herein, a process that integrates the pretreatment and relithiation of the cathode black mass is demonstrated. Cathode material from EoL electric vehicle (EV) batteries is treated in a 100 g per batch operation and the regenerated cathode active material demonstrates 100% electrochemical performance recovery, with 91% yield rate, and shows promise for further scale up. This process has the advantages of integration, scalability, and universality, which clears the barricade for direct recycling to move from lab to industry scale with considerable profitability.

Chemistry↗
DOE OSTI2024

Operando Investigation on the Role of Densification and Chemo-Mechanics on Solid-State Cathodes

All solid-state batteries are desirable for a range of energy storage applications which require high energy density. Achieving a high energy density in a solid-state battery requires the operation of an energy dense anode with a composite solid-state cathode. Pores and/or voids within a solid state cathode are ion-blocking and thus control over the concentration and distribution of pores in the initial electrode and cycled electrode is desirable. This study provides an understanding of the interplay between electrode microstructure and mechanics on active material utilization in solid state cathodes composed of NCM 811 and Li 6 PS 5 Cl. Decreasing the solid electrolyte particle size leads to greater active material-electrolyte contact and less total deformation when exposed to an external load. Composite cathodes with greater compliance can potentially decrease strain between the active material and solid electrolyte, decrease delamination events and result in higher overall active material utilization and high capacity retention.

25 ENERGY STORAGE↗
DOE OSTI2025

Cost‐Effective and Scalable Approach for the Separation and Direct Cathode Recovery from End‐of‐Life Li‐Ion Batteries

Li-ion battery recycling presents a promising opportunity to decrease dependence on foreign sources of materials and harvest precious materials within the United States. Herein, a superior complete direct recycling process on individual end-of-life cells is reported where the recovered high-purity cathode active material, as well as electrolyte salt Li hexafluorophosphate (LiPF 6 ) can be reused without significant processing. This new process utilizes a series of mechanical separation steps that enable the separation of the cathode and anode active materials while they are still attached to their current collectors. Using this type of process can significantly reduce metal contamination and enable a clean cathode that can be directly recycled. The process if implemented commercially can greatly reduce the environmental burden of batteries as the greenhouse gas emissions of 8.25 kg CO 2 e kg −1 from the direct recycling process are 64% lower compared to those from virgin production of cathode material. During electrochemical testing of the recovered LiNi 0.6 Mn 0.2 Co 0.2 O 2 a discharge capacity of ≈160 mAh g −1 and good cyclability of over 250 cycles at 0.33C are achieved. This success paves a new pathway to explore and optimize existing Li-ion battery recycling procedures.

electrolyte reuse↗
DOE OSTI2018

A Universal Organic Cathode for Ultrafast Lithium and Multivalent Metal Batteries

Abstract Low‐cost multivalent battery chemistries (Mg 2+ , Al 3+ ) have been extensively investigated for large‐scale energy storage applications. However, their commercialization is plagued by the poor power density and cycle life of cathodes. A universal polyimides@CNT (PI@CNT) cathode is now presented that can reversibly store various cations with different valences (Li + , Mg 2+ , Al 3+ ) at an extremely fast rate. The ion‐coordination charge storage mechanism of PI@CNT is systemically investigated. Full cells using PI@CNT cathodes and corresponding metal anodes exhibit long cycle life (>10000 cycles), fast kinetics (>20 C), and wide operating temperature range (−40 to 50 °C), making the low‐cost industrial polyimides universal cathodes for different multivalent metal batteries. The stable ion‐coordinated mechanism opens a new foundation for the development of high‐energy and high‐power multivalent batteries.

Fan, Xiulin↗
DOE OSTI2023

Thermal Stability and Outgassing Behaviors of High‐nickel Cathodes in Lithium‐ion Batteries

Abstract LiNiO 2 ‐based high‐nickel layered oxide cathodes are regarded as promising cathode materials for high‐energy‐density automotive lithium batteries. Most of the attention thus far has been paid towards addressing their surface and structural instability issues brought by the increase of Ni content (>90 %) with an aim to enhance the cycle stability. However, the poor safety performance remains an intractable problem for their commercialization in the market, yet it has not received appropriate attention. In this review, we focus on the gas generation and thermal degradation behaviors of high‐Ni cathodes, which are critical factors in determining their overall safety performance. A comprehensive overview of the mechanisms of outgassing and thermal runaway reactions is presented and analyzed from a chemistry perspective. Finally, we discuss the challenges and the insights into developing robust, safe high‐Ni cathodes.

Cui, Zehao↗
DOE OSTI2023

Speciation of Transition Metal Dissolution in Electrolyte from Common Cathode Materials

Abstract Significant capacity loss has been observed across extended cycling of lithium‐ion batteries cycled to high potential. One of the sources of capacity fade is transition metal dissolution from the cathode active material, ion migration through the electrolyte, and deposition on the solid‐electrolyte interphase on the anode. While much research has been conducted on the oxidation state of the transition metal in the cathode active material or deposited on the anode, there have been limited investigations of the oxidation state of the transition metal ions dissolved in the electrolyte. In this work, X‐ray absorption spectroscopy has been performed on electrolytes extracted from cells built with four different cathode active materials (LiMn 2 O 4 (LMO), LiNi 0.5 Mn 1.5 O 4 (LNMO), LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811), and (x Li 2 MnO 3 *(1‐x) LiNi a Mn b Co c O 2 , with a+b+ c =1) (LMRNMC)) that were cycled at either high or standard potentials to determine the oxidation state of Mn and Ni in solution. Inductively coupled plasma‐mass spectrometry has been performed on the anodes from these cells to determine the concentration of deposited transition metal ions. While transition metal ions were found dissolved in all electrolytes, the oxidation state(s) of Mn and Ni were determined to be dependent on the cathode material and independent of cycling potential.

Rynearson, Leah↗
DOE OSTI2023

Annealing in Argon Universally Upgrades the Na‐Storage Performance of Mn‐Based Layered Oxide Cathodes by Creating Bulk Oxygen Vacancies

Abstract Manganese‐rich layered oxide cathodes of sodium‐ion batteries (SIBs) are extremely promising for large‐scale energy storage owing to their high capacities and cost effectiveness, while the Jahn–Teller (J–T) distortion and low operating potential of Mn redox largely hinder their practical applications. Herein, we reveal that annealing in argon rather than conventional air is a universal strategy to comprehensively upgrade the Na‐storage performance of Mn‐based oxide cathodes. Bulk oxygen vacancies are introduced via this method, leading to reduced Mn valence, lowered Mn 3 d‐ orbital energy level, and formation of the new‐concept Mn domains. As a result, the energy density of the model P2‐Na 0.75 Mg 0.25 Mn 0.75 O 2 cathode increases by ≈50 % benefiting from the improved specific capacity and operating potential of Mn redox. The Mn domains can disrupt the cooperative J–T distortion, greatly promoting the cycling stability. This exciting finding opens a new avenue towards high‐performance Mn‐based oxide cathodes for SIBs.

Chemistry↗
DOE OSTI2025

Understanding the Benefit of Hybrid Electrolytes towards Vanadium Dissolution Suppression and Improved Capacity Retention in Zinc‐Aqueous Batteries Using NaV 3 O 8 Cathodes

Vanadate cathodes used in aqueous Zn-ion batteries with ZnSO 4 are hindered by capacity loss from V dissolution into the electrolyte. However, studies pinpointing the onset of dissolution as a function of electrochemical redox state and quantifying the amount of associated active material are lacking. To prevent dissolution of the NaV 3 O 8 active material, Na + ions are introduced into the electrolyte. Specifically, a hybrid ZnSO 4 + Na 2 SO 4 electrolyte is investigated in concert with NaV 3 O 8 (NVO) cathodes of varied crystallinity to determine the resulting impacts on cathode dissolution and functional electrochemistry. The use of Na + -containing hybrid electrolyte shows no significant change in Zn 2+ diffusion coefficients yet improved capacity retention. Time-resolved quantitative optical emission spectroscopy demonstrates the suppression of V dissolution with the hybrid electrolyte in both pristine and cycled electrodes. Operando synchrotron X-ray diffraction and absorption provide mechanistic insights. Hydrated NVO with wider interplanar spacing exhibits much higher H + /Zn 2+ capacity, while the Na 2 SO 4 mitigates the formation of irreversible side products. Furthermore, this study demonstrates that the use of hybrid electrolytes and control of crystallite size in the parent material can significantly improve electrochemical behavior of layered V-based cathodes in Zn-ion batteries, providing a general strategy toward safe and resilient aqueous battery systems.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Insight into Ca-Substitution Effects on O3-Type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Cathode Materials for Sodium-Ion Batteries Application

O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NaNFM) is well investigated as a promising cathode material for sodium-ion batteries (SIBs), but the cycling stability of NaNFM still needs to be improved by using novel electrolytes or optimizing their structure with the substitution of different elements sites. To enlarge the alkali-layer distance inside the layer structure of NaNFM may benefit Na + diffusion. Herein, the effect of Ca-substitution is reported in Na sites on the structural and electrochemical properties of Na 1-x Ca x/2 NFM (x=0, 0.05, 0.1). X-ray diffraction (XRD) patterns of the prepared Na 1-x Ca x/2 NFM samples show single alpha-NaFeO 2 type phase with slightly increased alkali-layer distance as Ca content increases. The cycling stabilities of Ca-substituted samples are remarkably improved. The Na 0.9 Ca 0.05 Ni 1/3 Fe 1/3 Mn 1/3 O 2 (Na 0.9 Ca 0.05 NFM) cathode delivers a capacity of 116.3 mAh g -1 with capacity retention of 92% after 200 cycles at 1C rate. In operando XRD indicates a reversible structural evolution through an O3-P3-P3-O3 sequence of Na 0.9 Ca 0.05 NFM cathode during cycling. Compared to NaNMF, the Na 0.9 Ca 0.05 NFM cathode shows a wider voltage range in pure P3 phase state during the charge/discharge process and exhibits better structure recoverability after cycling. The superior cycling stability of Na 0.9 Ca 0.05 NFM makes it a promising material for practical applications in sodium-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2018

Atomic layer deposition of Pt@CsH 2 PO 4 for the cathodes of solid acid fuel cells

Atomic layer deposition (ALD) has been used to apply continuous Pt films on powders of the solid acid CsH 2 PO 4 (CDP), in turn, used in the preparation of cathodes in solid acid fuel cells (SAFCs). The film deposition was carried out at 150 °C using trimethyl(methylcyclopentadienyl)platinum (MeCpPtMe 3 ) as the Pt source and ozone as the reactant for ligand removal. Chemical analysis showed a Pt growth rate of 0.09 ± 0.01 wt%/cycle subsequent to an initial nucleation delay of 84 ± 20 cycles. Electron microscopy revealed the contiguous nature of the films prepared using 200 or more cycles. The cathode overpotential (0.48 ± 0.02 V at a current density of 200 mA/cm 2 ) was independent of Pt deposition amount beyond the minimum required to achieve these continuous films. The cell electrochemical characteristics were moreover extremely stable with time, with the cathode overpotentials increasing by no more than 10 mV over a 100 h period of measurement. So, ALD holds promise as an effective tool in the preparation of SAFC cathodes with high activity and excellent stability.

25 ENERGY STORAGE↗
DOE OSTI2020

Dry-pressed lithium nickel cobalt manganese oxide (NCM) cathodes enabled by holey graphene host

There is an increasing demand for electric vehicle batteries with higher energy densities that can be manufactured with low cost utilizing environmentally friendly processes. Lithium nickel cobalt manganese oxides (NCM), such as LiNi(0.5)Co(0.2)Mr(0.3)O(2) (NCM523), are commonly used in commercial lithium ion batteries for electric vehicle applications. These cathodes are typically fabricated using environmentally hazardous, energy intensive, and time-consuming solvent-based slurry casting processes. Polymeric binders, also required for cathode preparation, add weight and can undergo parasitic reactions during battery cycling. Here we report a facile, solvent-free, binder-free, and rapid cold-press electrode fabrication process to prepare high mass loading NCM cathodes within minutes. This process is enabled by the use of holey graphene, a unique lightweight, compressible carbon nanomaterial that serves as both a binder and an electrically conductive matrix. NCM cathodes fabricated by this method are stable and exhibit good active material utilization. A significant advantage for the dry-press process is that the electrode mass loadings can be readily increased simply by adding more composite powder to the compression molding die, resulting in improved areal capacities that are attractive for applications requiring high energy per unit footprint. (C) 2020 Elsevier Ltd. All rights reserved.

25 ENERGY STORAGE↗
DOE OSTI2022

Artificial cathode electrolyte interphase for improving high voltage cycling stability of thick electrode with Co-free 5 V spinel oxides

Spinel-type cathode LiNi 0.5 Mn 1.5 O 4 (LNMO) has intrigued the transportation industry due to its high operating voltage and total elimination of the expensive cobalt element. However, LNMO cathode with high mass loading (> 3 mAh/cm 2 in areal capacity) has suffered from excessive capacity degradation upon long cycling. Here, a robust Al 2 O 3 surface layer is introduced to the thick LNMO electrode via atomic layer deposition (ALD). The capacity retention in full cells with the graphite anode is improved from 46.3% to 75.3% after 300 cycles with cutoff voltage up to 4.85 V, while enabling average Coulombic efficiency of 99.9% during the cycling. The post-mortem analyses reveal that the Al 2 O 3 surface layer would convert to Al-O-F /Al-F species upon cycling, offering stable interphase to protect the cathode material. Furthermore, these results demonstrate the significance of surface modification enabling high voltage cathode for next-generation LIBs.

25 ENERGY STORAGE↗
DOE OSTI2019

Beneficial rheological properties of lithium-ion battery cathode slurries from elevated mixing and coating temperatures

It is crucial that lithium-ion battery manufacturers implement strategies to expedite production without sacrificing quality due to rising consumer demand. Cathode coating is commonly performed at the industrial scale with a slot-die coater. In slot-die coating, substrate velocity is maximized and imperfections (such as air entrainment and thickness variations) are minimized by reducing the viscosity of the material being coated. A simple, scalable technique of reducing the viscosity of the cathode slurry is to increase its temperature, though it is dire that this heat does not cause irreversible gelation or otherwise deteriorate the slurry constituents. Cathode slurries were prepared at different mixing temperatures between 25 °C and 75 °C and their flow behavior was studied at their mixing temperature. At practical shear rates, the slurry coated at 60 °C was 23% less viscous than that coated at 25 °C, meaning the critical coating speed could be increased by roughly 14% at 60 °C. Between 25 °C and 60 °C, the slurries’ yield stress and equilibrium storage modulus increased monotonically, providing the additional benefit of higher sedimentation resistance of the active materials. To examine the influence of temperature on coating morphology and electrochemical performance, slurries were prepared and coated at 25 °C and 60 °C. Micrographs revealed no superficial differences between coatings. The electrode coated at 60 °C demonstrated comparable capacity retention during long-term cycling and high-rate discharge testing when compared to the electrode coated at 25 °C. The findings of this study indicate that warmer mixing and coating operations serve to maximize cathode productivity, particularly if advancements can be made in industrial-scale electrode drying.

25 ENERGY STORAGE↗
DOE OSTI2026

Hydrogen production from full-strength corn stover fermentation effluent in single-chamber replaceable-cathode microbial electrolysis cells

Lignocellulosic residual biomass generated by the agricultural sector is an abundant feedstock for biohydrogen production via dark fermentation. However, this process is intrinsically inefficient, converting only ~30% of the reductant energy into H2 and leaving substantial amounts of reduced byproducts. These byproducts, mostly found in the fermentation effluents, can be further valorized in microbial electrolysis cells (MECs) to enhance the overall H2 recovery. However, current MEC configurations are typically dual- or single-chamber systems, yet both suffer from key inefficiencies. Dual-chamber systems rely on proton exchange membranes that are costly and prone to rapid biofouling, whereas single-chamber, membraneless systems are limited by reduced productivity due to H2 recycling and methanogenic consumption In this study, three single-chamber, 50-mL replaceable-cathode microbial electrolysis cells (RC-MECs) were 3D-printed and equipped with a physical separator to isolate anode and cathode compartments and limit H2 migration. Full-strength milled corn stover (MCS) fermentation effluent (COD of ~23.8 g-COD/L) was treated in fed-batch mode over two operational periods spanning 21 (Run 1) and 80 (Run 2) days. The RC-MECs exhibited comparable performance in both runs: after biofilm maturation, current densities exceeded 100 A/m²_cathode, COD removal reached up to 43%. Notably, extended RC-MECs operation led to a substantial methanogenic activity with the CH4 fraction in the cathode gas increasing to as high as 80% of the total biogas. Additions of a methanogenesis inhibitor 2-bromoethanesulfonate (2-BES) produced transient increases in hydrogen yields (11.51 and 5.12 L-H2/L_reactor/day in Runs 1 and 2, respectively); however, sustained 2-BES addition in subsequent cycles reduced total biogas production, decreased COD removal, and led to volatile fatty acid accumulation. Overall, single-chamber MECs can treat high-strength dark fermentation effluents while improving H2 recovery, but methanogenesis remains a key bottleneck, and complete long-term inhibition may be operationally unsustainable.

Hydrogen Production↗
DOE OSTI2020

A scalable approach of using biomass derived glycerol to synthesize cathode materials for lithium-ion batteries

Glycerol, a main byproduct of biodiesel, was used as the fuel agent in a scalable flame-assisted spray pyrolysis approach to synthesize micron-size cathode materials. Single droplet combustion, particle morphology, and electrochemical performance were examined considering the effects of salt concentration, water addition, and post-annealing time on synthesizing Li(Ni 1/3 Co 1/3 Mn 1/3 )O 2 (NCM111) cathode materials. Single droplet tests showed that a sufficient amount of water in the glycerol-based precursor could delay droplet inflation and ignition. Moreover, using a two-fluid atomization nozzle, spray tests demonstrated that adding water would result in less wrinkled and more uniform particles. Nevertheless, increasing water proportion in the precursor could reduce the reaction heat, resulting in that samples prepared with water addition needed longer post-annealing time to improve their electrochemical performance. Using the precursor without water, the best performed NCM111 cathode material was synthesized with only 2 h of post-annealing. It has a discharge capacity of 163.3 mAh/g at 0.1C and 85.5% capacity retention at 1C after 100 cycles. Furthermore, the current work confirmed the capability of using glycerol as a sustainable fuel agent to synthesize NCM111 cathode materials, and also provided basic conditions for the development of large-scale production in the future.

25 ENERGY STORAGE↗