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Results for “layered metal oxides”

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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Activating Layered Metal Oxide Nanomaterials via Structural Engineering as Biodegradable Nanoagents for Photothermal Cancer Therapy

Layered metal oxides including MoO 3 and WO 3 have been widely explored for biological applications owing to their excellent biocompatibility, low toxicity, and easy preparation. However, they normally exhibit weak or negligible near-infrared (NIR) absorption and thus are inefficient for photo-induced biomedical applications. Herein, the structural engineering of layered MoO 3 and WO 3 nanostructures is first reported to activate their NIR-II absorption for efficient photothermal cancer therapy in the NIR-II window. White-colored micrometre-long MoO 3 nanobelts are transformed into blue-colored short, thin, defective, interlayer gap-expanded MoO 3–x nanobelts with a strong NIR-II absorption via the simple lithium treatment. The blue MoO 3–x nanobelts exhibit a large extinction coefficient of 18.2 L g –1 cm –1 and high photothermal conversion efficiency of 46.9% at 1064 nm. After surface modification, the MoO 3–x nanobelts can be used as a robust nanoagent for photoacoustic imaging-guided photothermal therapy to achieve efficient cancer cell ablation and tumor eradication under irradiation by a 1064 nm laser. Importantly, the biodegradable MoO 3–x nanobelts can be rapidly degraded and excreted from body. We report the study highlights that the structural engineering of layered metal oxides is a powerful strategy to tune their properties and thus boost their performances in given applications.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Controlling Surface Phase Transition and Chemical Reactivity of O3-Layered Metal Oxide Cathodes for High-Performance Na-Ion Batteries

O3-layered metal oxides are promising cathode materials for high-energy Na-ion batteries (SIBs); however, they suffer from fast capacity fade. In this work, we develop a high-performance O3-NaNi 0.68 Mn 0.22 Co 0.10 O 2 cathode for SIBs toward practical applications by suppressing the formation of a rock salt layer at the cathode surface with an advanced electrolyte. The cathode can deliver a high specific capacity of ~196 mAh g –1 and demonstrates >80% capacity retention over 1000 cycles. NaNi 0.68 Mn 0.22 Co 0.10 O 2 –hard carbon full-cells with practical loading (>2.5 mAh cm –2 ) and lean electrolyte (~40 μL) demonstrate ~82% capacity retention after 450 cycles. A 60 mAh single-layer pouch cell has also been fabricated and demonstrated stable performance. This work represents a significant leap in SIB development and brings new insights to the development of advanced layered metal oxide cathodes for alkaline-ion batteries.

25 ENERGY STORAGE↗
DOE OSTI2024

Suppressing Atmospheric Degradation of Sulfide-Based Solid Electrolytes via Ultrathin Metal Oxide Layers

Sulfide-based solid-state electrolytes (SSEs) are promising materials with superior Li-ion conductivity; however, their poor atmospheric stability limits commercial manufacturing at scale. Here, we investigate the impact of ultrathin metal oxide layers deposited via atomic layer deposition (ALD) on the stability of Li 6 PS 5 Cl (LPSCl). Al 2 O 3 layers grown directly on LPSCl particles significantly stabilize the surface chemistry and Li-ion transport properties relative to uncoated material upon exposure to both an ambient atmosphere (22% relative humidity, RH) and humidified O 2 (100% RH). Detailed investigations indicate that coatings impede the surface and bulk degradation kinetics of exposed materials, even for coatings as thin as ∼1 Å. Furthermore, this suggests that stabilization is due to more than just a physical barrier. Shifts in valence band edge positions of coated LPSCl indicate that ALD coatings alter the surface electronic structure and resulting oxidation tendency of underlying LPSCl, suggesting new avenues to improving the environmental stability of sulfide SSEs.

Atmospheric chemistry↗
DOE OSTI2021

Nanostructured, Targeted Layered Metal Oxides as Active and Selective Heterogeneous Electrocatalysts for Oxygen Evolution

Oxygen evolution reaction (OER) is an important chemical transformation that governs the performance of technologically relevant energy conversion and storage processes, such as electrochemical water splitting in electrolyzers and metal-air batteries. This reaction involves the evolution of oxygen gas from (i) oxygen ions formed from water splitting at high temperatures, (ii) oxygen containing species (i.e., OH, OOH) formed from water splitting at low temperatures, and (iii) metal-oxide discharge products (M x O 2 ) in metal-air batteries. One of the main challenges with OER is that it is catalyzed at low temperatures by noble metal-based electrocatalysts, which are expensive (making this process economically unviable), or at high temperatures by metal-oxide based electrocatalysts that are inefficient and lead to high overpotential losses. Our preliminary results, as well as other results in the literature, show that non-noble metal-based oxide electrocatalysts with layered structures, known as nickelate oxides, exhibit promising OER activity. Nickelate oxides (A 2 MO 4+δ ) belong to the Ruddlesden-Popper series composed of alternating perovskite-like and rocksalt-like layers. They are promising OER electrocatalysts due to their high oxygen transport/exchange properties compared to the state-of-the-art perovskite-type oxides. Unfortunately, these materials are fairly unexplored and little is known about the properties that govern their OER activity. Our preliminary studies, where we combine density functional theory (DFT) calculations, selective synthesis and characterization, show that engineering their nanocrystalline structure can significantly impact their catalytic activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

The Role of Metal Substitution in Tuning Anion Redox in Sodium Metal Layered Oxides Revealed by X-Ray Spectroscopy and Theory

We investigate high-valent oxygen redox in the positive Na-ion electrode P2-Na 0.67-x [Fe 0.5 Mn 0.5 ]O 2 (NMF) where Fe is partially substituted with Cu (P2-Na 0.67-x [Mn 0.66 Fe 0.20 Cu 0.14 ]O 2 , NMFC) or Ni (P2-Na 0.67 -x[Mn 0.65 Fe 0.20 Ni 0.15 ]O 2 , NMFN). From combined analysis of resonant inelastic X-ray scattering and X-ray near-edge structure with electrochemical voltage hysteresis and X-ray pair distribution function profiles, we correlate structural disorder with high-valent oxygen redox and its improvement by Ni or Cu substitution. Density of states calculations elaborate considerable anionic redox in NMF and NMFC without the widely accepted requirement of an A-O-A' local configuration in the pristine materials (where A=Na and A'=Li, Mg, vacancy, etc.). We also show that the Jahn–Teller nature of Fe 4+ and the stabilization mechanism of anionic redox could determine the extent of structural disorder in the materials. These findings shed light on the design principles in TM and anion redox for positive electrodes to improve the performance of Na-ion batteries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

The Role of Metal Substitution in Tuning Anion Redox in Sodium Metal Layered Oxides Revealed by X‐Ray Spectroscopy and Theory

Abstract We investigate high‐valent oxygen redox in the positive Na‐ion electrode P2‐Na 0.67− x [Fe 0.5 Mn 0.5 ]O 2 (NMF) where Fe is partially substituted with Cu (P2‐Na 0.67− x [Mn 0.66 Fe 0.20 Cu 0.14 ]O 2 , NMFC) or Ni (P2‐Na 0.67− x [Mn 0.65 Fe 0.20 Ni 0.15 ]O 2 , NMFN). From combined analysis of resonant inelastic X‐ray scattering and X‐ray near‐edge structure with electrochemical voltage hysteresis and X‐ray pair distribution function profiles, we correlate structural disorder with high‐valent oxygen redox and its improvement by Ni or Cu substitution. Density of states calculations elaborate considerable anionic redox in NMF and NMFC without the widely accepted requirement of an A‐O‐A′ local configuration in the pristine materials (where A=Na and A′=Li, Mg, vacancy, etc.). We also show that the Jahn–Teller nature of Fe 4+ and the stabilization mechanism of anionic redox could determine the extent of structural disorder in the materials. These findings shed light on the design principles in TM and anion redox for positive electrodes to improve the performance of Na‐ion batteries.

Abate, Iwnetim↗
DOE OSTI2025

Enhanced Activity in Layered Metal-Oxide-Based Oxygen Evolution Catalysts by Layer-by-Layer Modulation of Metal-Ion Identity

Few-layered potassium nickel and cobalt oxides show drastic differences in catalytic activity based on metal ion preorganization. Uniform compositions [(CoO 2 /K) 6 or (NiO 2 /K) 6 ] show limited activity, while homogeneously mixed-metal cobalt/nickel oxides [(Co n Ni (1–n) O 2 /K) 6 ] display moderate improvement. However, a layer-by-layer arrangement of alternating cobalt and nickel oxide sheets [e.g., (CoO 2 /K/NiO 2 /K)] provides superior catalytic performance, reducing the oxygen evolution overpotential by ∼200–400 mV. Density functional theory simulations provide an illustration of the electronic properties (density of states and localization of orbitals) that promote catalysis in the layer-segregated materials over those of homogeneous composition. This study reveals that atomic preorganization of metal ions within layered catalysts plays a more crucial role than the overall metal composition in enhancing catalytic efficiency for oxygen evolution.

catalysts↗
DOE OSTI2024

The Role and Substitution of Cobalt in the Cobalt‐Lean/Free Nickel‐Based Layered Transition Metal Oxides for Lithium Ion Batteries

Here, the Nickel-based layered transition metal oxide cathode represented by NCM (LiNi x Co y Mn z O 2 , x+y+z=1) and NCA (LiNi x Co y Al z O 2 , x+y+z=1) is widely used in the electric vehicle market due to its specific capacity and high working potential, in which Cobalt (Co) plays a huge role in improving the structural stability during the cycle. However, the limited supply of Co, due to its scarcity and the influence of geopolitics, poses a significant constraint on the further advancement of the Nickel-based layered transition metal oxide cathode in the field of energy storage. In this paper, the mechanism of Co in the Nickel-based layered transition metal oxides is reviewed, including its critical role for structural stability such as the inhibition of cationic mixing and the release of lattice oxygen et al. Subsequently, it outlines various strategies to enhance the performance of Co-lean/free materials, such as ion doping, including single-ion doping and multi-ion co-doping, and various surface coating strategies, so as to eliminate the adverse effects of Co loss on materials. Ultimately, this paper offers a glimpse into the promising future of Cobalt-free strategies for high performance of Nickel-based layered transition metal oxides.

25 ENERGY STORAGE↗
DOE OSTI2022

Multiphase layered transition metal oxide positive electrodes for sodium ion batteries

Abstract Multiphase layered transition metal oxides (LTMOs) for sodium ion battery (SIB) positive electrodes with phase interfaces across multiple length scales are a promising avenue toward practical, high‐performance SIBs. Combinations of phases can complement each other's strengths and mitigate their weaknesses if their interfaces are carefully controlled. Intra‐ and interparticle phase interactions from nanoscale to macroscale must be carefully tuned to generate distinct effects on properties and performance. An informed design strategy must be paired with relevant synthesis techniques and complemented by spatially resolved characterization tools to manipulate different length scales and interfaces. This review examines the design, synthesis, and characterization strategies that have been demonstrated for the preparation of heterogeneous, multiphasic LTMOs with phase interfaces across varied length scales.

25 ENERGY STORAGE↗
DOE OSTI2021

Tailoring the Surface of Metal Halide Perovskites to Enable the Atomic Layer Deposition of Metal Oxide Contacts

Replacing organic contact layers with inorganic counterparts, such as metal oxides, is one strategy for improving long-term device stability in metal halide perovskite solar cells. Often, the methods used to deposit metal oxide thin films are incompatible with metal halide perovskites, creating challenges for the fabrication of contacts above the perovskite absorber layer. In this study, we utilize a one-step, solution treatment of the top surface of Cs 0.25 FA 0.75 Pb(Br 0.20 I 0.80 ) 3 to create a thin (~1 nm) overlayer of lead sulfide (PbS) to protect the underlying perovskite during subsequent deposition. X-ray characterization of the surface region shows that the PbS overlayer limits undesirable changes to the perovskite structure and stoichiometry during atomic layer deposition (ALD) of SnO 2 . This protection enables ALD growth of SnO 2 electron contacts on top of the perovskite without an organic transport layer (e.g., C 60 ), resulting in a solar cell with a power conversion efficiency of 5.8%. This result is a marked improvement over devices with ALD SnO 2 grown directly on the perovskite without a PbS overlayer, which produce no power output. Furthermore, the interface characterization and device results in this study highlight some of the key challenges associated with ALD metal oxide growth on perovskite materials and can help inform the future design of inorganic contact layer deposition in solar photovoltaic technologies.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Surface Oxygen Depletion of Layered Transition Metal Oxides in Li-Ion Batteries Studied by Operando Ambient Pressure X-ray Photoelectron Spectroscopy

A new operando spectro-electrochemical setup was developed to study oxygen depletion from the surface of layered transition metal oxide particles at high degrees of delithiation. An NCM111 working electrode was paired with a chemically delithiated LiFePO 4 counter electrode in a fuel cell-inspired membrane electrode assembly (MEA). A propylene carbonate-soaked Li-ion conducting ionomer served as an electrolyte, providing both good electrochemical performance and direct probing of the NCM111 particles during cycling by ambient pressure X-ray photoelectron spectroscopy. The irreversible emergence of an oxygen-depleted phase in the O 1s spectra of the layered oxide particles was observed upon the first delithiation to high state-of-charge, which is in excellent agreement with oxygen release analysis via mass spectrometry analysis of such MEAs. By comparing the metal oxide-based O 1s spectral features to the Ni 2p 3/2 intensity, we can calculate the transition metal-to-oxygen ratio of the metal oxide close to the particle surface, which shows good agreement with the formation of a spinel-like stoichiometry as an oxygen-depleted phase. This new setup enables a deeper understanding of interfacial changes of layered oxide-based cathode active materials for Li-ion batteries upon cycling.

25 ENERGY STORAGE↗
DOE OSTI2026

Photoelectron Spectroscopic Determination of the Interfacial Energetics of Metal Oxide Protection Layers on p-InP Photocathodes

The interfacial energetics between p-type InP and a series of metal oxides, including TiO 2 , Nb 2 O 5 , Ta 2 O 5 , and HfO 2 , were evaluated using X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and optical absorption spectroscopy. The energy of the conduction-band minimum ( E cb ) of TiO 2 and Nb 2 O 5 was more negative (i.e., further from the vacuum level) than the conduction-band minimum at the surface of InP ( E cb,s ), whereas E cb for Ta 2 O 5 and HfO 2 was more positive than E cb,s for InP. The data are consistent with the electrochemical behavior of p-InP coated with various metal oxide candidate protection layers, with TiO 2 and Nb 2 O 5 facilitating interfacial transfer of photogenerated minority-carrier electrons in p-InP photocathodes, and Ta 2 O 5 and HfO 2 blocking photogenerated electrons in p-InP from readily transferring across the oxide-coated photocathodes. The energy of the valence-band maximum ( E vb ) for all of the oxides was much more negative than E vb,s for InP, consistent with observations that these protection layers effectively block hole transport and consequently suppress oxidative degradation of the underlying p-InP photocathodes.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2025

Review of Layered Transition Metal Oxide Materials for Cathodes in Sodium-Ion Batteries

The growing interest in sodium-ion batteries (SIBs) is driven by scarcity and the rising costs of lithium, coupled with the urgent need for scalable and sustainable energy storage solutions. Among various cathode materials, layered transition metal oxides have emerged as promising candidates due to their structural similarity to lithium-ion battery (LIB) counterparts and their potential to deliver high energy density at reduced costs. However, significant challenges remain, including limited capacity at high charge/discharge rates and structural instability during extended cycling. Addressing these issues is critical for advancing SIB technology toward industrial applications, particularly for large-scale energy storage systems. This review provides a comprehensive analysis of layered sodium transition metal oxides, focusing on their structural properties, electrochemical performance, and degradation mechanisms. Special attention is given to the intrinsic and extrinsic factors contributing to their instability, such as structural phase transitions, and cationic/anionic redox behavior. Additionally, recent advancements in material design strategies, including doping, surface modifications, and composite formation, are discussed to highlight the progress toward enhancing the stability and performance of these materials. This work aims to bridge the knowledge gaps and inspire further innovations in the development of high-performance cathodes for sodium-ion batteries.

Ahangari, Mehdi (ORCID:0000000345803969)↗
DOE OSTI2022

Techno-economic analysis of the use of atomic layer deposited transition metal oxides in silicon heterojunction solar cells

The industry for producing silicon solar cells and modules has grown remarkably over the past decades, with more than a 100-fold reduction in price over the past 45?years. The main solar cell fabrication technology has shifted over that time and is currently dominated by the passivated emitter and rear cell (PERC). Other technologies are expected to increase in market share, including tunnel-oxide passivated contact (TOPCon) and heterojunction technology (HJT). In this paper, we examine the cost potential for using atomic layer deposition (ALD) to form transition metal oxide (TMO) layers (MoO x , TiO x and aluminium-doped zinc oxide [AZO]) to use as lower cost alternatives of the p-doped, n-doped and indium tin oxide (ITO) layers, respectively, the layers normally used in HJT solar cells. Using a bottom-up cost and uncertainty model with equipment cost data and process experience in the lab, we find that the production cost of these variations will likely be lower per wafer than standard HJT, with the main cost drivers being the cost of the ALD precursors at high-volume production. We then considered what efficiency is required for these sequences to be cost effective in $/W and discuss whether these targets are technically feasible. This work motivates further work in developing these ALD TMO processes to increase their efficiency towards their theoretical limits to take advantage of the processing cost advantage.

14 SOLAR ENERGY↗
DOE OSTI2020

Intrinsic Kinetic Limitations in Substituted Lithium-Layered Transition-Metal Oxide Electrodes

Substituted Li-layered transition-metal oxide (LTMO) electrodes such as Li x Ni y Mn z Co 1-y-z O 2 (NMC) and Li x Ni y Co 1-y-z Al z O 2 (NCA) show reduced first cycle Coulombic efficiency (90-87% under standard cycling conditions) in comparison with the archetypal Li x CoO 2 (LCO; similar to 98% efficiency). Focusing on Li x Ni 0.8 Co 0.15 Al 0.0.5 O 2 as a model compound, we use operando synchrotron X-ray diffraction (XRD) and nuclear magnetic resonance (NMR) spectroscopy to demonstrate that the apparent first-cycle capacity loss is a kinetic effect linked to limited Li mobility at x > 0.88, with near full capacity recovered during a potentiostatic hold following the galvanostatic charge- discharge cycle. This kinetic capacity loss, unlike many capacity losses in LTMOs, is independent of the cutoff voltage during delithiation and it is a reversible process. The kinetic limitation manifests not only as the kinetic capacity loss during discharge but as a subtle bimodal compositional distribution early in charge and, also, a dramatic increase of the charge-discharge voltage hysteresis at x > 0.88. 7 Li NMR measurements indicate that the kinetic limitation reflects limited Li transport at x > 0.86. Electrochemical measurements on a wider range of LTMOs including Li x (Ni,Fe) y Co 1-y O 2 suggest that 5% substitution is sufficient to induce the kinetic limitation and that the effect is not limited to Ni substitution. In this paper, we outline how, in addition to a reduction in the number of Li vacancies and shrinkage of the Li-layer size, the intrinsic charge storage mechanism (two-phase vs solid-solution) and localization of charge give rise to additional kinetic barriers in NCA and nonmetallic LTMOs in general.

25 ENERGY STORAGE↗