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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

High-rate and long-life lithium-ion battery performance of hierarchically hollow-structured NiCo 2 O 4 /CNT nanocomposite

In this paper, 3D-transition binary metal oxides have been considered as promising anode materials for lithium-ion batteries with improved reversible capacity, structural stability and electronic conductivity compared with single metal oxides. Here, carbon nanotube supported NiCo 2 O 4 nanoparticles (NiCo 2 O 4 /CNT) with 3D hierarchical hollow structure are fabricated via a simple one-pot method. The NiCo 2 O 4 nanoparticles with interconnected pores are consists of small nanocrystals. When used as anode material for the lithium-ion battery, NiCo 2 O 4 /CNT exhibits enhanced electrochemical performance than that of Co 3 O 4 /CNT and NiO/CNT. Moreover, ultra-high discharge/charge stability was obtained for 4000 cycles at a current density of 5 A g –1 . The superior battery performance of NiCo 2 O 4 nanoparticles is probably attributed to the special structural features and physical characteristics, including integrity, hollow structure with interconnected pores, which providing sufficient accommodation for the volume change during charge/discharge process. Besides, the consisting of ultra-small crystals enhanced the utility of active material, and intimate interaction with CNTs improved the electron-transfer rate.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Morphology- and lattice stability-dependent performance of nanostructured Li 4 Ti 5 O 12 probed by in situ high-pressure Raman spectroscopy and synchrotron X-ray diffraction

Nanostructured Li 4 Ti 5 O 12 (LTO) as a promising anode material in lithium-ion batteries (LIBs) has shown excellent yet morphology-dependent performance in LIB operations. However, the structural origin that influences the material performance at the microscopic level remains unclear. In this work, using combined in situ Raman spectroscopy and synchrotron X-ray diffraction, we comparatively investigated the structural stability of two nanostructured LTO materials with different morphologies by application of external pressure up to 27 GPa. In particular, nanoflower-like Li 4 Ti 5 O 12 spheres (LTO-1) and Li 4 Ti 5 O 12 nanoparticles (LTO-2) were subjected to high pressures using diamond anvil cells and their structural evolutions were characterized upon compression and decompression. Raman measurements show that both LTO materials undergo pressure-induced structural disorder but with different reversibilities upon decompression. X-ray results further confirmed the Raman measurements, and also allowed the quantitative analysis of pressure dependence of the crystal structures. Structural refinements of the diffraction patterns yield morphology-dependent bulk moduli of the two LTO materials, which reveal critical information about the intrinsic lattice strain and vacancies. These different structural characteristics, when compared with another spinel structure of lithiated titanium dioxide, allow the interpretation of the different performance between LTO-1 and LTO-2 for LIB operations. This study thus contributes to the understanding of the important factors that may influence the electrochemical performance and help with the design of new LTO-based anode materials for LIBs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Exfoliated MoS 2 Sheets and Reduced Graphene Oxide-An Excellent and Fast Anode for Sodium-ion Battery

Three dimensional (3D) MoS 2 nanoflowers are successfully synthesized by hydrothermal method. Further, a composite of as prepared MoS 2 nanoflowers and rGO is constructed by simple ultrasonic exfoliation technique. The crystallography and morphological studies have been carried out by XRD, FE-SEM, TEM, HR-TEM and EDS etc. Here, XRD study revealed, a composite of exfoliated MoS 2 with expanded spacing of (002) crystal plane and rGO can be prepared by simple 40 minute of ultrasonic treatment. While, FE-SEM and TEM studies depict, individual MoS 2 nanoflowers with an average diameter of 200 nm are uniformly distributed throughout the rGO surface. When tested as sodium-ion batteries anode material by applying two different potential windows, the composite demonstrates a high reversible specific capacity of 575 mAhg -1 at 100 mAg -1 in between 0.01 V–2.6 V and 218 mAhg -1 at 50 mAg -1 when discharged in a potential range of 0.4 V–2.6 V. As per our concern, the results are one of the best obtained as compared to the earlier published one on MoS 2 based SIB anode material and more importantly this material shows such an excellent reversible Na-storage capacity and good cycling stability without addition of any expensive additive stabilizer, like fluoroethylene carbonate (FEC), in comparison to those in current literature.

36 MATERIALS SCIENCE↗
NASA NTRS1991

Advances In Li-TiS2 Cell Techno1ogy

JPL is involved in a NASA sponsored program to develop ambient temperature secondary Lithium - Titanium Disulfide Cells for future space missions. After several years of research on various lithium systems, the Li-TiS2 system was selected for development in view of its practically realizable high specific energy. In the last two years, the efforts were focused on improving the cycle life of the system and optimizing the cell design. A number of approaches, such as the use of mixed solvent electrolytes, the use of alternate anode materials, the operation of cells at low temperature, and the cycling of cells under optimized voltage limits, are examined to improve cycle life performance of this system. Cycling studies in small 150 mAh cell have identified 1.5 M LiAsF6/2-MeTHF, 1.5 M LiAsF6/EC+2-eTHF, and 1.5 M LiAsF6/THF+2-MeTHF+2-MeF as promising electrolytes for Li-TiS2 cells. Li-Al and Li-C were selected for further assessment as candidate anode materials after a detailed theoretical and experimental evaluation. Cycling of the cells at low temperature did not result in improving the cycle life of the cells. Charge and discharge voltage limits were found to have significant influence on the cycle life of the cells activated with 1.5 M LiAsF6/THF+2-MeTHF+2-MeF electrolyte. The influence of design variables, such as ratio of electrode capacity, quantity of electrolyte, pack tightness, cell configuration, etc., on the cycle life performance are being examined as a part of the design optimization study. Spiral-wound 1 Ah cells fabricated for the design studies have completed more than 500 cycles at 50% DOD. This paper summarizes the advances made in the Li-TiS2 technology at JPL since 1989.

Surampudi, S.↗
DOE OSTI2022

Systems and methods for electrical energy storage

The present disclosure relates to an electrical energy storage apparatus which forms an interpenetrating, three dimensional structure. The structure may have a first non-planar channel filled with an anode material to form an anode, and a second non-planar channel adjacent the first non-planar channel filled with a cathode material to form a cathode. A third non-planar channel may be formed adjacent the first and second non-planar channels and filled with an electrolyte. The first, second and third channels are formed so as to be interpenetrating and form a spatially dense, three dimensional structure. A first current collector is in communication with the first non-planar channel and forms a first electrode, while a second current collector is in communication with the second non-planar channel and forms a second electrode. A separator layers separates the current collectors.

Duoss, Eric B.↗
DOE OSTI2025

Metallicity, Atomic Disorder, and Li-Ion Storage in Fast-Charging Anodes

Oxides of Nb with Wadsley-Roth shear structures comprise a family of stable, high-rate anode materials for Li-ion batteries. A particular pair of them offers the unusual opportunity to test how important metallic conduction of the starting electrode is for electrode performance. The selected pair of compounds with similar 4 × 3 Wadsley-Roth block structures are insulating Ti 2 Nb 10 O 29 and metallic Nb 12 O 29 . A combination of diffraction, electrochemistry, magnetic measurements, and entropic potential measurements is employed to establish key findings for these two anode materials. We find that starting with a metallic oxide is not especially advantageous over a comparable material that readily transitions into a metallic state upon lithiation. Second, the rate performance appears to be dictated by ion mobility, and atomic Ti/Nb disorder in Ti 2 Nb 10 O 29 contributes to improved capacity retention at high rates by suppressing Li-ion ordering. However, subtle details in the nature of redox processes make Nb 12 O 29 a slightly better electrode material for long-term cycling at slower rates.

crystal structure↗
DOE OSTI2021

Hydrophobic versus Hydrophilic Interfacial Coatings on Silicon Nanoparticles Teach Us How to Design the Solid Electrolyte Interphase in Silicon-Based Li-Ion Battery Anodes

Herein, we evaluate the effect of covalently attached molecular coating hydrophobicity on the surface of the silicon nanoparticle (Si NP) active anode material for Li-ion batteries. The experiments are a means to identify the interfacial properties that help minimize electrochemical side reactions during cycling. Preformed coatings on the Si NP surfaces prior to electrode fabrication mimic the ionically conducting and electronically insulating properties of the solid electrolyte interphase (SEI). Hydrophilic oligomers such as polyethylene oxide (PEO) and other related structures are commonly identified as Li+-conducting components of the SEI. Here, we study the effect of such hydrophilic PEO versus hydrophobic alkyl molecular coatings on Si NP anode electrochemical performance. We also study the effect of the PEO oligomer length and the resulting effective thickness of the interfacial coating on the electrochemical performance. We find that PEO oligomers electrochemically isolate Si NPs when the PEO coating thickness approaches the electron tunneling distance of ~2.5 nm. Surprisingly, the thickness of the PEO-based coatings has a negligible effect on their ability to minimize electrochemical side reactions as measured by Coulombic efficiency. These results reveal how the interfacial coating on silicon anode materials should differ from an operando-formed SEI layer and discuss design strategies for an ideal interfacial active material coating based on these results.

25 ENERGY STORAGE↗
DOE OSTI2020

Microscopic Observation of Solid Electrolyte Interphase Bilayer Inversion on Silicon Oxide

Silicon has been investigated in recent years as an alloying anode material to enhance gravimetric energy density in lithium-ion batteries. Although recent developments have suggested that silicon oxides exhibit improved cycling stability over pure Si, the origin of the improved cycling performance is still poorly understood. The initial solid electrolyte interphase (SEI) formation mechanisms on Si wafers with both native oxide and chemically etched thermal oxide coatings are investigated structurally, chemically, and morphologically in the nanoscale. After one electrochemical cycle, microscopy reveals that SEI formed on native SiO x features the typical SEI bilayer structure with a carbon-rich outer SEI layer and an inorganic-rich inner SEI layer. In contrast, the SEI formed on chemically etched thermal oxide shows an inversion in the structure. This work observes distinct initial SEI formation mechanisms on the HF-etched SiO 2 surface, which may be partially responsible for improved cycle life observed in SiO x -based anode materials.

25 ENERGY STORAGE↗
DOE OSTI2014

The reaction mechanism of SnSb and Sb thin film anodes for Na-ion batteries studied by X-ray diffraction, 119 Sn and 121 Sb Mössbauer spectroscopies

The electrochemical reaction of Sb and SnSb anode materials with Na results in the formation of amorphous materials. To understand the resulting phases and electrochemical capacities we studied the reaction products local order using 119 Sn and 121 Sb Mössbauer spectroscopies in conjunction with measurements performed on model powder compounds of Na-Sn and Na-Sb to further clarify the reactions steps. For pure Sb the discharge (sodiation) starts with the formation of an amorphous phase composed of atomic environments similar to those found in NaSb, and proceeds further by the formation of environments similar to that present in Na 3 Sb. The reversible reaction takes place during a large portion of the charge process. At full charge the anode material still contains a substantial fraction of Na, which explains the lack of recrystallization into crystalline Sb. The reaction of SnSb yields Na 3 Sb crystalline phase at full discharge at higher temperatures (65 and 95°C) while the room temperature reaction yields amorphous compounds. The electrochemically-driven, solid-state amorphization reaction occurring at room temperature is governed by the simultaneous formation of Na-coordinated Sn and Sb environments, as monitored by the decrease (increase) of the 119 Sn ( 121 Sb) Mössbauer isomer shifts. Overall, the monitoring of the hyperfine parameters enables to correlate the changes in Na content to the individual Sn and Sb local chemical environments.

25 ENERGY STORAGE↗
DOE OSTI2017

Size-controllable porous NiO electrodes for high-performance lithium ion battery anodes

Highlights: • Size-controllable porous NiO electrodes were prepared by a simple thermal oxidation route. • The prepared porous NiO electrodes exhibit high capacity and excellent rate capability and cycling stability. • The smaller nanopore and crystallite size are benefical to improve the electrochemical properties of the porous NiO electrodes. - Abstract: Size-controllable porous NiO electrodes were prepared by a simple and easily scalable thermal oxidation route and were evaluated as anode materials for lithium ion batteries. The nanopore size of the prepared electrodes can be obtained in the range from 20 to 80 nm by varying the thermal oxidation condition. Lithium storage performance measurement showed that porous NiO electrodes exhibit high capacity and excellent rate capability and cycling stability. Furthermore, it was shown that the smaller nanopore and crystallite size are beneficial to improve the electrochemical properties of the porous NiO electrodes.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Interface-engineered (CrMnTiZnCo) 3 O 4 @polypyrrole nano-hybrids for superior lithium storage

High-entropy oxides (HEO) have emerged as promising anode materials for lithium-ion batteries (LIBs) due to their high theoretical specific capacity. However, their practical application is hindered by several challenges, including significant volume expansion, electrode pulverization, and substantial irreversible capacity loss during initial cycles. To address these limitations, this study designed a novel core-shell composite material, denoted as HEO@PPy, which consists of a (CrMnTiZnCo) 3 O 4 -based HEO core and a polypyrrole (PPy) shell. This composite demonstrates remarkable electrochemical performance: it maintains a specific capacity of 1090.1 mAh/g after 100 cycles at 100 mA/g and retains 521.8 mAh/g after 1000 cycles at 1 A/g, highlighting its superior cycling stability. Furthermore, it exhibits excellent rate capability, delivering a capacity of 372.1 mAh/g even at a high current density of 5 A/g. These findings confirm that the strategic compositional and structural design of HEOs, combined with hybridization with conductive polymers like PPy, provides a viable pathway for developing advanced anode materials for next-generation, high-performance lithium-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2019

Computational design of CO-tolerant Pt 3 M anode electrocatalysts for proton-exchange membrane fuel cells

CO is a typical contaminant in hydrogen fuel produced via steam reforming. Development of a CO-tolerant Pt-based anode for the proton-exchange membrane fuel cells (PEMFC) is of great interest to avoid catalyst deactivation caused by strong CO adsorption on Pt. Pt–Ru, Pt–Mo, and Pt 3 Sn are three known Pt-based bimetallic CO-tolerant anode materials. The enhanced CO-tolerance of these alloys has been generally attributed to a bifunctional effect enabling oxidative CO removal at low applied potential and a ligand effect between the two metals which weakens CO bonding and reduces CO surface coverage. In this study, we use density functional theory to calculate surface adsorption states under reaction conditions for Pt-based alloys. Our calculations provide a molecular-level understanding of the enhanced CO-tolerance of Pt alloys induced by the second metal. We find that Mo and Sn dopants promote CO-tolerance by reducing CO surface coverage and enabling CO oxidative removal at low applied potential. In contrast, Ru is not able to promote CO electro-oxidation at the low applied potential of the operating conditions of a PEMFC anode. The CO-tolerance induced by Ru is attributed to the reduction of CO coverage on Pt sites. Based on these mechanisms, we carried out a computational screening of Pt 3 M electrocatalysts for CO-tolerant PEMFC anodes. A number of promising candidates have been identified for experimental examination.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

Microwave-assisted synthesis of Co{sub 3}O{sub 4}–graphene sheet-on-sheet nanocomposites and electrochemical performances for lithium ion batteries

Highlights: • Co{sub 3}O{sub 4}–graphene nanocomposites are prepared by microwave irradiation method. • Co{sub 3}O{sub 4} nanosheets exhibit porous structure with the pore sizes of 3–6 nm. • The porous Co{sub 3}O{sub 4}–graphene nanocomposites show excellent electrochemical performance. • Synergistic effects of Co{sub 3}O{sub 4} and graphene improve the electrochemical performance. - Abstract: Porous Co{sub 3}O{sub 4} nanosheets anchored on graphene nanosheets were synthesized by microwave irradiation method. The obtained Co{sub 3}O{sub 4}–graphene sheet-on-sheet nanocomposite as an anode material for LIBs demonstrates a high initial discharge capacity of 1359.6 mAh g{sup −1} with a Columbic efficiency of 72.7% at a rate of 100 mA g{sup −1}. Moreover, a significantly enhanced reversible capacity of ∼1036.9 mAh g{sup −1} is retained after 50 cycles, and the capacity can reincrease to 1068 mAh g{sup −1} when the current density returns back to 100 mA g{sup −1} after cycled at various rates for 50 cycles. The improved electrochemical performance is attributed to the unique architectures of the porous Co{sub 3}O{sub 4} nanosheets and the incorporation of graphene nanosheets. Therefore, this nanocomposite is widely considered to be an attractive candidate as an anode material for next-generation LIBs.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Accurate Determination of Coulombic Efficiency for Lithium Metal Anodes and Lithium Metal Batteries

Lithium (Li) metal is an ideal anode material for high energy density batteries. However, its low Coulombic efficiency (CE) and formation of dendrites during the plating and stripping processes has hindered its applications in rechargeable Li metal batteries. The accurate measurement of Li CE is a critical factor to predict the cycle life of Li metal batteries, but the measurement of Li CE is affected by various factors that often leads to conflicting values reported in the literature. Here, we investigate various factors that affect the measurement of Li CE and propose a more accurate method of determining Li CE. It was also found that the capacity used for cycling greatly affects the stabilization cycles and the average CE. A higher cycling capacity leads to a shorter number of stabilization cycles and higher average CE. With a proper high-concentration ether-based electrolyte, Li metal can be cycled with a high average CE of 99.5 % for over 100 cycles at a high capacity of 6 mAh cm-2 suitable for practical applications.

Adams, Brian D.↗
DOE OSTI2015

Investigation of carbon-coated lithiated Li{sub 4+x}Ti{sub 5}O{sub 12}/C for lithium-ion batteries

Highlights: • Lithiated Li{sub 4+x}Ti{sub 5}O{sub 12}/C with pre-stored active Li ions has been synthesized. • The first-cycle coulombic efficiency of Li{sub 4+x}Ti{sub 5}O{sub 12}/C is over 100%. • Li{sub 4+x}Ti{sub 5}O{sub 12}/C displays excellent cyclic stability and capacity retention. • TiO{sub 2} nanoparticles and carbon coating are necessary for formation of Li{sub 4+x}Ti{sub 5}O{sub 12}/C. - Abstract: Carbon-coated Li{sub 4}Ti{sub 5}O{sub 12} and lithiated Li{sub 4+x}Ti{sub 5}O{sub 12} anode materials have been synthesized using nanosized anatase TiO{sub 2} and commercial TiO{sub 2} with mixed structure as Ti sources, respectively. Microstructural investigation indicates that Li{sub 4}Ti{sub 5}O{sub 12} and Li{sub 4+x}Ti{sub 5}O{sub 12} are covered by amorphous carbon layers with thickness of 2–3 nm. Their electrochemical performance has been evaluated, which indicates that an amount of active Li ions have been pre-stored in the Li{sub 4+x}Ti{sub 5}O{sub 12} lattice during solid-state synthesis, resulting in its first-cycle coulombic efficiency over 100%. Further, Li{sub 4+x}Ti{sub 5}O{sub 12}/C exhibits higher cyclic capacities than Li{sub 4}Ti{sub 5}O{sub 12}/C at different current density. The reversible charge capacity retention of Li{sub 4+x}Ti{sub 5}O{sub 12}/C reaches 98.5% after 100 cycles, which indicates that Li{sub 4+x}Ti{sub 5}O{sub 12}/C is promising candidate anode material for long lifetime lithium-ion batteries. The formation mechanism of Li{sub 4+x}Ti{sub 5}O{sub 12}/C has been discussed, in which the nanosized anatase TiO{sub 2} with high chemical activity and the carbon coating play key roles for the formation of Li{sub 4+x}Ti{sub 5}O{sub 12}/C.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Hard Carbon as Sodium-Ion Battery Anodes: Progress and Challenges

Hard carbon (HC) is the state-of-the-art anode material for Na-ion batteries due to its excellent overall performance, wide availability and relatively low cost. Recently, tremendous effort has been carried out to elucidate the Na storage mechanism in HC and to explore synthesis approaches that can enhance the performance and lower the cost. However, disputations remain in the fields, particularly on the fundamental questions of ion transfer and storage and the ideal HC structure for high performance. This mini-review aims to give an analysis and summary of the theoretical limitations of HC, discrepancies of the storage mechanism, and methods to improve the performance. In the end, future research on developing ideal structured HC, advanced electrolyte and optimized electrolyte-electrode interphase are proposed on the basis of recent progress.

Xiao, Biwei↗
DOE OSTI2015

Combustion synthesized rod-like nanostructure hematite with enhanced lithium storage properties

Graphical abstract: Fe{sub 2}O{sub 3} nanorods are synthesized by combustion method using alcohol as both solvent and fuel. As an anode material for lithium-ion batteries, the Fe{sub 2}O{sub 3} nanorod electrode delivers good electrochemical performance. - Highlights: • We prepared Fe{sub 2}O{sub 3} nanorod by a facile and powerful combustion method. • The Fe{sub 2}O{sub 3} nanorod shows high capacity, good cycle stability, and rate performance. • Combustion saves time and energy to meet the demand of green and sustainable industry. - Abstract: Fe{sub 2}O{sub 3} nanorods are synthesized by combustion method using alcohol as both solvent and fuel, which is a facile and effective strategy for the large-scale and inexpensive fabrication. The Fe{sub 2}O{sub 3} nanorods are with the well distributed diameters of 20–30 nm and length ranging from 80 to 100 nm. As an anode material for lithium-ion batteries, the Fe{sub 2}O{sub 3} nanorod electrode delivers a high discharge capacity of 761.7 mA h g{sup −1} after 60 cycles at 500 mA g{sup −1}, and 727.2 mA h g{sup −1} at a high current density of 2000 mA g{sup −1}. The good electrochemical performance is attributed to the sufficient contact of active material and electrolyte, large surface area, and short diffusion length of Li{sup +}.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Zero-strain high entropy spinel oxide (FeNiCuCrMn) 3 O 4 @rGO as high-performance anode for sodium ion battery

High entropy spinel oxides (HEOs), as a new type of anode material with at least five transition metal elements and high theoretical specific capacity, have enormous promise in sodium ion batteries (SIBs). However, the influence of different transition metal elements on the structure and electrochemical performances of HEOs is not clear. Here, in this study, the addition of Mn to HEO can increase the surface oxygen vacancy (O v ) concentration, shorten the band gap, and enhance the electrochemical performance of (FeNiCuCrMn) 3 O 4 @rGO. XPS results show (FeNiCuCrMn)3O4@rGO has the highest surface O v concentration. Ab initio calculations demonstrate that the indirect band gap of (FeNiCuCrMn)3O4@rGO is 0.068 eV. In situ X-ray diffraction and synchrotron X-ray absorption spectroscopy reveal that (FeNiCuCrMn) 3 O 4 @rGO exhibits a zero-strain characteristic with an inconsequential unit cell volume change of 0.2 %. Specifically, (FeNiCuCrMn) 3 O 4 @rGO as anode materials for SIBs show good cyclic stability (with a capacity retention of 84 % at 500 mA g −1 after 3000 cycles). Overall, this work provides a new direction for optimizing transition metal elements in HEOs.

36 MATERIALS SCIENCE↗