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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Ionothermally Synthesized Nanoporous Ti 0.95 W 0.05 Nb 2 O 7 : a Novel Anode Material for High-Performance Lithium-Ion Batteries

Although TiNb 2 O 7 is regarded as a fast-rechargeable lithium-ion battery (LIB) anode material, the intrinsic poor electrochemical kinetics of TiNb 2 O 7 still dramatically impedes its development. Herein, an ionothermal synthesis-assisted doping strategy is proposed for the preparation of a new W 6+ -doped TiNb 2 O 7 material (Ti 0.95 W 0.05 Nb 2 O 7 ) with nanoporous structure (denoted as NPTWNO). The improved Li + diffusion coefficient of NPTWNO suggests that the ionic-liquid-templated nanoporous architecture improves the Li+ diffusion kinetics. The density functional theory computational study reveals that the doped W 6+ successfully boosts the electronic conductivity due to the narrowed conduction-valance bandgap resulted from charge redistribution, which is reflected by the electrochemical impedance spectroscopy data. With the simultaneously enhanced Li+ diffusivity and electronic conductivity, NPTWNO achieves fast-rechargeability in LIBs. So this work indicates the potential of ionothermal synthesis-assisted doping strategy on energy storage materials and offers NPTWNO material with promising electrochemical performance.

25 ENERGY STORAGE↗
DOE OSTI2020

Single-Layer Dititanium Oxide Ti 2 O MOene: Multifunctional Promises for Electride, Anode Materials, and Superconductor

Using the first-principles calculations, we report the existence of the single-layer (SL) dititanium oxide Ti 2 O (labeled as MOene) that constructs a novel family of MXene based on transition-metal oxides. This MOene material strongly contrasts the conventional ones consisting of transition-metal carbides and/or nitrides. SL Ti 2 O has high thermal and dynamical stabilities because of the strong Ti–O ionic bonding interactions. Moreover, this material is an intrinsic electride and exhibits extremely low diffusion barriers of ~12.0 and 6.3 meV for Li and Na diffusion, respectively. When applied as anode materials in lithium-ion batteries and sodium-ion batteries, it possesses a high energy storage capacity (960.23 mAhg –1 ), surpassing the traditional MXenes-based anodes. The superb electrochemical performance stems from the existing anionic electron on Ti 2 O surface. Astonishingly, SL Ti 2 O is also determined to be a superconductor with a superconducting transition temperature (T c ) of ~9.8 K, which originates from the soft-mode of the first acoustic phonon branch and enhanced electron–phonon coupling in the low-frequency region. Furthermore, this soft-mode behaves much softer upon applying a compressive strain of 2%, leading to a higher T c of 11.9 K. Furthermore, our finding broadens the family of MXenes and could facilitate more experimental efforts toward future nanodevices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Low Cost Manufacturing of Advanced Silicon-Based Anode Materials

Under the financial support of award DE-EE0007312, Group14 Technologies (G14) has progressed from the lab (~g) to lab-pilot (~kg) manufacturing of a novel silicon-carbon (Si-C) composite that is highly promising as an anode material for next-generation lithium-ion batteries. G14’s Si-C is a drop in for graphite in lithium ion battery anodes, providing for increased energy density while lowering the cost on a capacity basis. At the foundation of the Si-C particle is an amorphous carbon scaffold, with its porosity fine-tuned for promoting intra-particle growth of the desired type and size (amorphous, nano-sized) of high capacity silicon, while also proving for internal volume to ameliorate silicon’s expansion upon lithiation. Both the carbon and silicon within the Si-C composite are produced from readily available, low-cost precursors. At lab scale, we demonstrated the ability to produce Si-C capable of achieving capacity of 1000 mAh/g with minimum 500 cycle stability (up to 1000 cycles with pre-lithiation) in full cell, coin cell lithium ion batteries. Based on such lab experience, we down-selected process and equipment suitable for producing Si-C at lab-pilot scale. The chosen equipment was purchased, installed and commissioned at Group14’s pilot manufacturing facility in Woodinville, WA. In turn, the ability to produce kg quantities facilitated the shipment of Si-C to various third parties. The promising feedback from such third parties included achievement of high first cycle efficiency (up to 92%) and 800 cycle stability in full cell, pouch cell lithium ion batteries. Beyond this highly promising electrochemical performance, it is important to note that G14’s Si-C has also been developed for low cost. Based on estimated production costs, electrochemical performance data, and modeling employing the BatPaC model, we project <$125/kWh for lithium ion battery packs containing G14’s Si-C.

25 ENERGY STORAGE↗
DOE OSTI2017

Structure-dependent performance of TiO 2 /C as anode material for Na-ion batteries

The performance of energy storage materials is highly dependent on their nanostructures. Herein, hierarchical rod-in-tube TiO 2 with a uniform carbon coating is synthesized as the anode material for sodium-ion batteries by a facile solvothermal method. This unique structure consists of a tunable nanorod core, interstitial hollow spaces, and a functional nanotube shell assembled from two-dimensional nanosheets. By adjusting the types of solvents used and reaction time, the morphologies of TiO 2 /C composites can be tuned to nanoparticles, microrods, rod-in-tube structures, or microtubes. Among these materials, rod-in-tube TiO 2 with a uniform carbon coating shows the highest electronic conductivity, specific surface area (336.4 m 2 g -1 ), and porosity, and these factors lead to the best sodium storage capability. Benefiting from the unique structural features and improved electronic/ionic conductivity, the as-obtained rod-in-tube TiO 2 /C in coin cell tests exhibits a high discharge capacity of 277.5 and 153.9 mAh g -1 at 50 and 5000 mA g -1 , respectively, and almost 100% capacity retention over 14,000 cycles at 5000 mA g -1 . In operando high-energy X-ray diffraction further confirms the stable crystal structure of the rod-in-tube TiO 2 /C during Na + insertion/extraction. Finally, this work highlights that nanostructure design is an effective strategy to achieve advanced energy storage materials.

25 ENERGY STORAGE↗
DOE OSTI2018

Oriented, One‐Dimensional Tin Dioxide–Titanium Dioxide Composites as Anode Materials for Lithium‐Ion Batteries

Abstract Highly oriented columnar nanostructures of tin dioxide (SnO 2 ) and a composite tin dioxide material with a thin titanium dioxide coating (SnO 2 –TiO 2 ) are fabricated using aerosol chemical vapor deposition (ACVD) and are utilized as high‐capacity anode materials in lithium‐ion batteries. The SnO 2 nanostructures exhibit a specific capacity of 445 mAh g −1 after 100 cycles at a rate of 1 C, but experience substantial capacity fade at a charge rate of 2 C, and a capacity of 251 mAh g −1 after 100 cycles. To enhance the capacity retention a coating of TiO 2 is applied to the electrodes. Comparatively, the SnO 2 –TiO 2 electrode exhibits a capacity of 497 mAh g −1 after 100 cycles at a charge rate of 2 C. Diffusion measurements indicate that no inhibition of lithium diffusion occurs due to a thin TiO 2 coating. The superior capacity retention of the composite electrode may be attributed to the protection of SnO 2 from irreversible reactions using a TiO 2 coating.

Kacica, Clayton T.↗
DOE OSTI2018

High capacity anode materials for lithium ion batteries

High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

25 ENERGY STORAGE↗
DOE OSTI2016

Ultrathin Li4Ti5O12 nanosheets as anode materials for lithium and sodium storage

Two-dimensional Li4Ti5O12 (LTO) nanosheets are prepared via a surfactant assisted hydrothermal process. Polyether (P123) was added as the surfactant to modify the surface and control the microstructure of the hydrothermal products and thus affect the electrochemical performance of the as-synthesized LTO anode material. XRD results show that the addition of P123 can restrain the growth of Li2TiO3 during the hydrothermal process, thus affecting the morphology and enhancing the rate performance of the final products. With the addition of P123, the growth of LTO can be restrained and ultrathin LTO nanosheets can be obtained after high temperature sintering, which is beneficial for the charge transfer and Li+ ion diffusion. The rate performance of these two different LTO materials is very different because of their differences in phase composition and fine morphology. The P123-assisted nanostructured LTO sample (P-LTO) shows a much higher rate capability than the LTO sample without P123, with over 130 mAh g-1 capacity retained at the charge-discharge rate of 64C when used in a lithium battery. For intercalation of larger size Na+ ions, the P-LTO still exhibit a capacity of 115 mAh g-1 at a charge (de-sodiation process) rate of 10C and maintains 96% capacity after 400 cycles

Environmental Molecular Sciences Laboratory↗
DOE OSTI2016

Correlating Titania Nanostructured Morphologies with Performance as Anode Materials for Lithium-Ion Batteries

Titanium oxide is a ubiquitous and commonly used material in the environment. Herein, we have systematically probed the use of various hydrothermally derived titania (TiO2) architectures including zero-dimensional (0D) nano-particles, one-dimensional (1D) nanowires, and three-dimensional (3D) urchin-like motifs as anode materials for lithium- ion batteries. The structure and morphology of these nanomaterials were characterized using electron microscopy. The surface areas of these materials were quantitatively analyzed through Brunauer-Emmett-Teller (BET) adsorption measurements and were found to be relatively similar for both 1D and 3D samples with a slightly higher surface area associated with the 0D nanoparticles. Hence, to normalize for the surface area effect, readily available 0D commercial nanoparticles (Degussa P25), which possessed a similar surface area to that of as-prepared 1D and 3D materials, were also analyzed. Electrochemical analysis revealed a superior performance of hydrothermally derived 3D urchin-like motifs as compared with both as-prepared 0D and 1D samples as well as commercial Degussa P25. Our studies suggest the greater overall importance of morphology as opposed to surface area in dictating the eficiency of the Li ion diffusion process. Specifically, the 3D urchins yielded consistent rate capabilities, delivering 214, 167, 120, 99, and 52 mAh/g under corresponding discharge rates of 0.1, 1, 10, 20, and 50 C, respectively. Moreover, these 3D motifs gave rise to a stable cycling performance, exhibiting a capacity retention of ~90% in cycles 1-100 under a discharge rate of 1 C. Furthermore, the rate capability and cycling performance of our 3D hierarchical motifs were (i) comparable to those of anatase TiO /TiO -(B) hybrid structures even with little if any electrochemically promising bronze (B) phase herein and (ii) clearly nced as compared with previous results using similar anatase 3D microspheres.

25 ENERGY STORAGE↗
DOE OSTI2018

Nanoparticles-constructed spinel ZnFe2O4 anode material with superior lithium storage performance boosted by pseudocapacitance

Highlights: • Nanoparticles-constructed ZnFe{sub 2}O{sub 4} was fabricated by co-precipitation method. • The ZnFe{sub 2}O{sub 4} sample shows excellent high rate capability and cycling stability. • The lithium storage mechanism was analyzed by CV and EIS measurements. • Pseudocapacitive effect has a significant contribution to the total stored charge. - Abstract: The practical application of ZnFe{sub 2}O{sub 4} in lithium ion batteries (LIBs) is severely hampered by its fast capacity fading and poor rate performance. To overcome these issues, herein, ZnFe{sub 2}O{sub 4} powders consist of aggregated nanoparticles (50∼100 nm) with porosity were prepared by a facile co-precipitation method and subsequent thermal decomposition. When used as anode material for LIBs, the ZnFe{sub 2}O{sub 4} sample delivers capacities of 920, 820, 650, 485, and 421 mA h g{sup −1} at current densities of 0.5, 1, 3, 7, and 10 A g{sup −1}, respectively. Moreover, the sample can maintain a capacity of 814 mA h g{sup −1} even after 300 cycles at the current density of 1 A g{sup −1}, implying an excellent rate capability and cycling stability. Cyclic voltammetry analysis reveals that both diffusion-controlled lithium storage and surface pseudocapacitive lithium storage contribute to the total stored charge of ZnFe{sub 2}O{sub 4}, which boosts the high rate capability and superior cycling stability of the ZnFe{sub 2}O{sub 4}.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Synergetic effect of carbon and AlF 3 coatings on the lithium titanium oxide anode material for high power lithium-ion batteries

A carbon coated commercial lithium titanium oxide (Li 4 Ti 5 O 12 ; LTO) was acoustically mixed with nano-sized AlF 3 and heat treated to form a simultaneous coating layer of carbon and AlF 3 on LTO particles. The surface modified LTO samples were characterized by a variety of means such as X-ray diffraction, Fourier transform infrared spectrometer, high-resolution transmission electron microscope, and inductively coupled plasma mass spectrometry. The results indicate that both carbon and AlF 3 layers exist on the surface of LTO particles and that the distribution of the carbon and AlF 3 differs depending on post heat treatment temperature. The carbon and AlF 3 coating layers formed by optimal post heat treatment at 350 °C significantly improves electrochemical performance, which increases charge capacity by 30% over the pristine LTO after 50 cycles at a high current density of 5C. Thus, LTO with a simultaneous coating layer of carbon and AlF 3 formed by acoustic mixing and post heat treatment shows a potential to further improve commercially-optimized carbon-coated LTO by alleviating its inherently low conductivity. In conclusion, this is an effective way to stabilize the interface between LTO particles and electrolyte, and is a practical approach to promote the wide usage of LTO, one of the most potent anode materials

25 ENERGY STORAGE↗
DOE OSTI2019

Tetragonal C 24 : a topological nodal-surface semimetal with potential as an anode material for sodium ion batteries

Na-ion batteries, as an alternative to Li-ion batteries, have gained increasing attention due to the abundance of sodium and its low cost. In the present work, we prepare a 3D porous carbon material by inserting hexagonal carbon rings into sp 3 C–C bonds in a previously established 3D-(4,4) lattice, termed tC 24 . Ab initio calculations uncover that not only is tC 24 thermally, dynamically and mechanically stable, but it also exhibits a unique electronic band structure with two topological nodal surfaces traversing through the whole Brillouin zone. More importantly, tC 24 is the first all carbon topological nodal-surface semimetal for Na-ion batteries, exhibiting a high theoretical capacity of 232.65 mA h g -1 , a low diffusion energy barrier for Na ions, an appropriate average voltage of 0.54 V and a negligible volume change (~0.94%) during charging/discharging operation. These properties provide tC 24 with a potentially long cycling life when used as an anode material for Na-ion batteries.

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

Operando study of mechanical integrity of high-volume expansion Li-ion battery anode materials coated by Al 2 O 3

Group IV elements and their oxides, such as Si, Ge, Sn and SiO have much higher theoretical capacity than commercial graphite anode. However, these materials undergo large volume change during cycling, resulting in severe structural degradation and capacity fading. Al 2 O 3 coating is considered an approach to improve the mechanical stability of high-capacity anode materials. To understand the effect of Al 2 O 3 coating directly, we monitored the morphology change of coated/uncoated Sn particles during cycling using operando focused ion beam–scanning electron microscopy. Here, the results indicate that the Al 2 O 3 coating provides local protection and reduces crack formation at the early stage of volume expansion. The 3 nm Al 2 O 3 coating layer provides better protection than the 10 and 30 nm coating layer. Nevertheless, the Al 2 O 3 coating is unable to prevent the pulverization at the later stage of cycling because of large volume expansion.

25 ENERGY STORAGE↗
DOE OSTI2018

The investigation of NaTi2(PO4)3@C/Ag as a high-performance anode material for aqueous rechargeable sodium-ion batteries

Highlights: • Facile preparation of NaTi{sub 2}(PO{sub 4}){sub 3}@C/Ag. • An extraordinary self-rejuvenation process was observed every other 20–30 cycles. • Retain a capacity of 71.7 mA h g{sup −1} even at 5 C after 200 cycles. - Abstract: Silver and carbon coated NaTi{sub 2}(PO{sub 4}){sub 3} is synthesized via a facile sol-gel method, with polyvinyl alcohol as carbon source and silver nitrate as Ag source. NaTi{sub 2}(PO{sub 4}){sub 3}@C/Ag is characterized by XRD, SEM, TEM, EDS and XPS. It can be found that C/Ag composite layer is uniformly coated on the surface of NaTi{sub 2}(PO{sub 4}){sub 3}. Compared with the pure NaTi{sub 2}(PO{sub 4}){sub 3}, NaTi{sub 2}(PO{sub 4}){sub 3}@C/Ag material demonstrates significantly higher rate capability and cycling stability. It can deliver an initial discharge capacity of 126.5 mA h g{sup −1} at a current rate of 2 C with the capacity retention of 94.5% after 100 cycles. It can still deliver an initial discharge capacity of 97.5 mA h g{sup −1} at a current rate of 5 C with a substantial capacity retention of 83.8% after 400 cycles. It is worth mentioning that NaTi{sub 2}(PO{sub 4}){sub 3}@C/Ag also exhibits pretty good rate capacity. When the current density ranges from 1 C, 2 C, 5 C, 10 C and finally back to 1 C, NaTi{sub 2}(PO{sub 4}){sub 3}@C/Ag electrode still retains a discharge capacity of 84.6 mAh g{sup −1} after 200 cycles at 5 C corresponding to a capacity retention ratio of 83.5%.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Three-dimensional electronic resistivity mapping of solid electrolyte interphase on Si anode materials

Silicon is a promising candidate for the lithium ion battery (LIB) anode because of the order-of-magnitude improvement in capacity over current state-of-the-art graphite anodes. In systems featuring both C and Si anodes, electronic resistivity of the solid-electrolyte interphase (SEI) layer is a critical factor for preventing continuous electrolyte-decomposition reactions at the electrode/electrolyte interface. However, the in-situ measurement of SEI electronic resistance has been complicated by ion transport and electronic contributions from other parts of the battery circuit. Ex-situ measurements of SEI resistivity at microscopic scales are also lacking. We report on a nanometer-resolution three-dimensional technique that enables ex-situ mapping of electronic resistivity of SEI formed on a model single-crystalline wafer Si anode. Our novel experimental approach uses scanning spreading-resistance microscopy resistance imaging and mechanical depth profiling. In addition to resistance mapping, this method also provides an alternative technique for locating buried interfaces, where mechanical or electronic properties differ sufficiently between layers. Further validation of this method was obtained by resistance mapping of a reference sample with a designed a-Si:H layer stack of different doping concentrations. The results show relatively uniform lateral resistivity distribution of the SEIs but steep decreases in resistivity in the vertical direction. Resistivity vs. depth profiles are highly dependent on cycling conditions, but they generally show a resistivity decrease from the most superficial levels of SEI and a thickness increase with continued cycling prior to SEI stabilization. The most prominent resistivity increase was observed on SEI formed in Gen2 electrolyte (EC:EMC [3:7 by wt.] + 1.2 M LiPF6) with 10 wt% fluoroethylene carbonate additive; this result may partially explain the significant improvements of sustained electrochemical cycling and coulombic efficiency observed with this electrolyte additive. Our approach provides a novel and unparalleled three-dimensional approach in characterizing electronic resistivity, which contributes significantly to understanding SEI formation and the intrinsic properties critical to battery performance.

25 ENERGY STORAGE↗
DOE OSTI2024

Phosphorus-carbon composites as battery anode materials

An electrochemical device includes an anode containing a phosphorus-carbon composite including a conductive carbon matrix and nano-sized phosphorus particles, wherein the nano-sized phosphorus particles are uniformly dispersed on the surface and/or pores of the carbon matrix.

Xu, Guiliang↗
DOE OSTI2017

Ex Situ Investigation of Anisotropic Interconnection in Silicon-Titanium-Nickel Alloy Anode Material

Herein we investigate the nanostructural evolution of Silicon-Titanium-Nickel (Si-Ti-Ni) ternary alloy material synthesized by melt spinning process for advanced lithium-ion battery anode. The synthesized material was found to have nano-Silicon particles dispersed in the Ti 4 Ni 4 Si 7 (STN) alloy buffering matrix and was characterized by X-ray diffraction (XRD), High resolution- transmission electron microscope (HR-TEM), Scanning transmission electron microscopes - energy dispersive X-ray spectrometer (STEM-EDS), and electrochemical performance test. The role of STN matrix is to accommodate the volume expansion stresses of the dispersed Si nanoparticles. However, an interesting behavior was observed during cycling. The Si nanoparticles were observed to form interconnection channels growing through the weak STN matrix cracks and evolving to a network isolating the STN matrix into small puddles. In conclusion, this unique nanostructural evolution of Si particles and isolation of the STN matrix failing to offer significant buffering effect to the grown Si network eventually accelerates more volume expansions during cycling due to less mechanical confinement and leads to performance degradation and poor cycle stability.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Lithium Metal Anode Materials Design: Interphase and Host

Abstract Li metal is the ultimate anode choice due to its highest theoretical capacity and lowest electrode potential, but it is far from practical applications with its poor cycle lifetime. Recent research progresses show that materials designs of interphase and host structures for Li metal are two effective ways addressing the key issues of Li metal anodes. Despite the exciting improvement on Li metal cycling capability, problems still exist with these methodologies, such as the deficient long-time cycling stability of interphase materials and the accelerated Li corrosion for high surface area three-dimensional composite Li anodes. As a result, Coulombic efficiency of Li metal is still not sufficient for full-cell cycling. In the near future, an interphase protected three-dimensional composite Li metal anode, combined with high performance novel electrolytes might be the ultimate solution. Besides, nanoscale characterization technologies are also vital for guiding future Li metal anode designs. Graphic Abstract

Wang, Hansen↗