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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

In situ ambient pressure XPS study of Pt/Cu(111) single-atom alloy in catalytically relevant reaction conditions

The presence of multiple reactant gases as well as reaction intermediates in a heterogeneous catalytic reaction results in a complex interaction between different components of the catalyst with each gas, which can alter the surface and chemical state of the catalyst differently than in the presence of an individual gas alone. In this study, we used in situ ambient pressure x-ray photoelectron spectroscopy to study the surface state of Pt/Cu(111) single-atom alloy model system in two catalytically relevant reaction conditions: CO 2 hydrogenation and CO oxidation. We found that the activation of CO 2 results in the formation of CO, which adsorbs on Pt sites at up to 400 K. In the presence of CO 2 and H 2 , Pt catalyzes the reverse water–gas shift reaction, which produces more CO and further stabilizes surface Pt atoms at 450 K. On the other hand, in CO oxidation condition, the presence of O 2 results in the formation of a thick Cu 2 O layer at higher temperatures, and Pt atoms are no longer detected in the surface and subsurface layers. When O 2 is introduced to the sample before CO, the formation of a complete Cu 2 O layer that covers all Pt atoms occurs immediately at room temperature. Finally, however, when CO is introduced at room temperature before O 2 , the presence of adsorbed CO on Pt sites stabilizes the surface Pt atoms and prevents the formation of a complete Cu 2 O layer, thus exposing the Pt atoms in 'holes' in the Cu 2 O layer.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Global gyro-kinetic ion temperature gradient and trapped electron mode turbulence modelling in X -point geometry in negative and positive triangularity

Comparative modelling of ion temperature gradient (ITG)/trapped electron mode (TEM) turbulence in negative (NT) and positive (PT) triangularity plasma shapes was done using the nonlinear global full-f gyrokinetic particle code JOREK-GK in the realistic X-point tokamak geometry including the Scrape Off Layer (SOL) for TCV and DIII-D parameters. A comparison of JOREK-GK code with the gyrokinetic codes GS2 and GENE was done using NT/PT triangularity TCV L-modes parameters showing good agreement between codes in linear growth rates and clear beneficial effect of NT as compared to PT. Global non-linear modelling of the ITG/TEM saturated turbulence for realistic DIII-D NT pulses was done and compared with numerically constructed PT equilibrium with the same plasma profiles. Existence of longer correlation length of density fluctuations in PT compared to NT was demonstrated. Stronger and more sheared zonal flows are generated via Reynolds stress in NT compared to PT. These factors are stabilizing for TEM/ITG turbulence in NT and lead to smaller heat fluxes and heat conductivities in NT compared to PT configuration. Weak dependence of plasma confinement on collisionality and plasma rotation was found in modelling of DIII-D NT shots similar to the experiment. The confinement scaling with normalized ion gyro-radius ρ* was estimated both for NT and PT. Bohm-like scaling was obtained in both configurations, however with better confinement for NT compared to PT which could be favourable factor for reactor size machines.

ITG↗
DOE OSTI2023

Do Melamine and Melamine-Formaldehyde Surface Modifiers Improve Fuel Cell Activity and Durability?

Precious group metal-based catalysts based on Pt- and Pt-alloys are currently used as catalysts for the kinetically sluggish Oxygen Reduction Reaction (ORR) on the cathode of fuel cells. The activity of Pt or Pt-alloy catalysts towards ORR is severely compromised by the adsorption of spectator-species such as sulfonate anions from perfluorosulfonic acid (PFSA) ionomer or Pt-O(H) ad via water activation. Considering recent evidence pointing to the improvement in ORR activity via the use of melamine organic molecule or melamine-formaldehyde copolymeric additives as surface blocking agents for the prevention of sulfonate or Pt-OH ad adsorption, we evaluated these additives in fuel cells. The catalysts were modified with either of these additives and characterized using ex situ and in situ methods to verify successful adsorption and eventual performance in fuel cells. These surface modifying agents were found to suppress Pt-OH ad formation as well as suppress ORR activity. There was no evidence to point out that these additives improved ORR activity and H 2 /air polarization performance in a fuel cell MEA on supported, polycrystalline Pt catalyst.

08 HYDROGEN↗
DOE OSTI2020

Meso-Structured Polymer Electrolyte Fuel Cell Electrode

Increasing the utilization of Pt and Pt alloy catalysts in polymer electrolyte fuel cell cathodes is critical to improving the high power density operation, particularly at low Pt loadings. State of the art electrodes are fabricated in an ink deposition process that leads to uncontrolled electrode architecture with random aggregates of functional domains (catalyst, ionomer, and pore volume) (1). The randomness in the domains induces high tortuosity transport pathways for ions and fluids, which cause severe transport resistance during high current density operation. Thin ionomer films cause additional transport resistance and poisoning of the Pt catalyst, which becomes more significant at low Pt loadings. Reducing the amount of ionomer in the catalyst domain without affecting the ionic transport resistance is key to improving the utilization of the Pt and reducing the transport resistance at low Pt loading. Rational design of the electrode structure with controlled low tortuous ionic transport pathways could improve performance. The introduction of the ionomer pathways could also enable reduction of the ionomer volume in the catalyst domain, reducing the transport resistance. Middelmen et al. proposed electrode structures consisting of aligned components in a low tortuosity configuration to improve performance (2). In this work, we present an alternative electrode structure based on a vertically aligned array of Nafion pillars in the cathode catalyst layer, as shown in Figure 1a. Figure 1b shows the SEM image of the Nafion pillars. Furthermore, Pt supported on carbon catalyst was deposited on the Nafion pillars to fabricate a meso-structured electrode. Nafion pillars provide high conductive and low tortuous pathways for protons, reducing the effective transport distance, and enabling reduction of the ionomer binder in the catalyst domain.

25 ENERGY STORAGE↗
DOE OSTI2026

Reactive Oxygen Ion Beam-Induced Deposition for Concurrent Purification of Platinum Nanostructures

Oxygen-focused ion beam induced deposition (O-FIBID) enables the direct-write fabrication of Pt nanostructures while simultaneously enhancing purity concurrently through reactive oxygen–deposit interactions. By systematically varying the dwell time, accelerating voltage, and precursor pressure, the Pt content and conductivity can be controlled. Under optimum conditions, the Pt content reached 63 at.%. Across the dwell-time range used for resistivity measurements, the Pt content increased from 20 to 33 at.%, while the resistivity decreased from 2.9 × 10 4 μΩ·cm to 1.2 × 10 3 μΩ·cm, which is consistent with enhanced percolation through Pt grains and the lower intrinsic resistivity of the purer Pt deposit. The simulation results support a purification mechanism driven by the beam-induced activation of implanted oxygen balanced against the preferential sputtering of Pt. These results demonstrate O-FIBID as a viable method for the nanoscale direct write of conductive Pt without post-processing, and some deviations from conventional FIBID wisdom are observed. These results serve as a foundation for exploring nascent, reactive focused ion beam-induced deposition processes.

deposit purification↗
DOE OSTI2025

Data for: Climatic Imprint on Interfacially-Controlled Platinum-Palladium Resources

Data package for manuscript "Climatic Imprint on Interfacially-Controlled Platinum-Palladium Resources" by Emily G. Wright, Ivey Wang, Yihang Fang, Elaine D. Flynn, and Jeffrey G. Catalano. This dataset contains adsorption results from experiments designed to investigate the effect of chloride on Pd(II) adsorption to goethite and Pt(II) adsorption to hematite and goethite, including lab experiments, X-ray absorption fine structure spectroscopy, and models of retention within a laterite. See the associated manuscript for full methods information. The file "Wright2025_PtAds_data.csv" contains the target starting Pt concentration (uM), final aqueous Pt and associated error (in uM), calculated adsorbed Pt and associated error (in umol/m2), target and measured aqueous chloride (mM), target aqueous nitrate (mM), final pH, and mineral concentration/loading (g/L). Associated mineral-free controls (mineral loading = 0 g/L) are included; the aqueous Pd error was not calculated and chloride was not measured in every sample. These data appear in Figures 1, S3, S4, S5, S20, and S22 in the associated manuscript. The file "Wright2025_PdAds_data.csv" contains the target starting Pd concentration (uM), final aqueous Pd and associated error (in uM), calculated adsorbed Pd and associated error (in umol/m2), target and measured aqueous chloride (mM), and mineral concentration/loading (g/L). Associated mineral-free controls (mineral loading = 0 g/L) are included; the aqueous Pd error was not calculated and chloride was not measured in every sample. These data appear in Figures 1, S3, S4, S5, and S20 in the associated manuscript. The file "Wright2025_MineralBatches_data.csv" contains the mineral identity and BET specific surface area (m2/g) for every mineral batch synthesized and used in experiments. The annealing time used is listed for hydrothermally annealed goethite. These data appear in Table S2 in the associated manuscript. The file "Wright2025_XRD_data.csv" contains the XRD patterns for every mineral batch synthesized as the counts as a function of two theta (in degrees). See "Wright2025_MineralBatches_data.csv" for more details on specific mineral batches. These data appear in Figure S2 in the associated manuscript. The file "Wright 2025_ZetaPotential_data.csv" contains the measured zeta potentials for samples of goethite (batch G2) at pH 4 the presence of varying amounts of sodium chloride. These data appear in Table S3 in the associated manuscript. The file "Wright2025_XAFSSamples_data.csv" contains the specific mineral batch, measured final aqueous Pd or Pt (uM), measured final aqueous chloride (mM), and estimated adsorbed Pd or Pt (umol/m2) of all XAFS samples. These data appear in Tables S4, S7, S8, and S10 in the associated manuscript. The files "Wright2025_PdXAFS_data.csv" and "Wright2025_PtXAFS_data.csv" contain the normalized spectra of Pd and Pt, respectively, adsorbed to minerals at varying chloride concentrations. See "Wright2025_XAFSSamples_data.csv" for a guide to sample names. Note that "05" in a sample name is equivalent to "0.5". These data appear in Figures 2, S6, S7, S8, S12, S13, and S14 in the associated manuscript. The file "Wright2025_LateriteProfileProfileModelParameters_data.csv" include the ratio of hematite to hematite and goethite in two synthetic, modeled profiles, as well as the modeled surface areas of goethite and hematite as a function of relative depth within the modeled weathering zone. These data were used, in conjunction with equations presented in the paper, to calculate the theoretical concentrations of Pd and Pt (and the resulting Pt/Pd ratio) within the profiles. These data appear in Figure 3 in the associated manuscript. The file "Wright2025_Imagery_data.zip" is a zipped folder containing the TEM and STEM images appear in Figures S18 and S19. Individual files are labeled as either STEM (Fig. S18) or TEM (Fig. S19) with a letter representing the part of the multipart figure.

58 GEOSCIENCES↗
NASA NTRS2005

Thermodynamic Effect of Platinum Addition to beta-NiAl: An Initial Investigation

An initial investigation was conducted to determine the effect of platinum addition on the activities of aluminum and nickel in beta-NiAl(Pt) over the temperature range 1354 to 1692 K. These measurements were made with a multiple effusion-cell configured mass spectrometer (multi-cell KEMS). The results of this study show that Pt additions act to decreased alpha(Al) and increased the alpha(Ni) in beta-NiAl(Pt) for constant X(sub Ni)/X(sub Al) approx. = 1.13, while at constant X(sub Al) the affect of Pt on Al is greatly reduced. The measured partial enthalpies of mixing indicate Al-atoms have a strong self interaction while Ni- and Pt-atoms in have similar interactions with Al-atoms. Conversely the binding of Ni-atoms in beta-NiAl decreases with Pt addition independent of Al concentration. These initial results prove the technique can be applied to the Ni-Al-Pt system but more activity measurements are required to fully understand the thermodynamics of this system and how Pt additions improved the scaling behavior of nickel-based superalloys. In addition, with the choice of a suitable oxide material for the effusion-cell, the "closed" isothermal nature of the effusion-cell allows the direct investigation of an alloy-oxide equilibrium which resembles the "local-equilibrium" description of the metal-scale interface observed during high temperature oxidation. It is proposed that with an Al(l) + Al2O3(s) experimental reference state together with the route measurement of the relative partial-pressures of Al(g) and Al2O(g) allows the activities of O and Al2O3 to be determined along with the activities of Ni and Al. These measurements provide a direct method of investigating the thermodynamics of the metal-scale interface of a TGO-scale.

Source record↗
NASA NTRS2005

Characterization of Ternary NiTiPt High-Temperature Shape Memory Alloys

Pt additions substituted for Ni in NiTi alloys are known to increase the transformation temperature of the alloy but only at fairly high Pt levels. However, until now only ternary compositions with a very specific stoichiometry, Ni50-xPtxTi50, have been investigated and then only to very limited extent. In order to learn about this potential high-temperature shape memory alloy system, a series of over twenty alloys along and on either side of a line of constant stoichiometry between NiTi and TiPt were arc melted, homogenized, and characterized in terms of their microstructure, transformation temperatures, and hardness. The resulting microstructures were examined by scanning electron microscopy and the phase compositions quantified by energy dispersive spectroscopy."Stoichiometric" compositions along a line of constant stoichiometry between NiTi to TiPt were essentially single phase but by any deviations from a stoichiometry of (Ni,Pt)50Ti50 resulted in the presence of at least two different intermetallic phases, depending on the overall composition of the alloy. Essentially all alloys, whether single or two-phase, still under went a martensitic transformation. It was found that the transformation temperatures were depressed with initial Pt additions but at levels greater than 10 at.% the transformation temperature increased linearly with Pt content. Also, the transformation temperatures were relatively insensitive to alloy stoichiometry within the range of alloys examined. Finally, the dependence of hardness on Pt content for a series of Ni50-xPtxTi50 alloys showed solution softening at low Pt levels, while hardening was observed in ternary alloys containing more than about 10 at.% Pt. On either side of these "stoichiometric" compositions, hardness was also found to increase significantly.

Rios, Orlando↗
NASA NTRS2007

Partitioning of Pd Between Fe-S-C and Mantle Liquids at High Pressure and Temperature: Implications for Core Formation

One of the most elusive geochemical aspects of the early Earth has been explaining the near chondritic relative abundances of the highly siderophile elements (HSE; Au, Re and the platinum group elements) in Earth's primitive upper mantle (PUM). Perhaps they were delivered to the Earth after core formation, by late addition of carbonaceous chondrite material. However, the recognition that many moderately siderophile elements can be explained by high pressure and temperature (PT) metal-silicate equilibrium, leads to the question whether high PT equilibrium can also explain the HSE concentrations. Answers to this question have been slowed by experimental difficulties (nugget effect and very low solubilities). But two different perspectives have emerged from recent studies. One perspective is that D(M/S) for HSE at high PT are not low enough to explain terrestrial mantle depletions of these elements (for Pd and Pt). A second perspective is D(M/S) are reduced substantially at high PT and even low enough to explain terrestrial mantle depletions (for Au and Pt). Issues complicating interpretation of all experiments include use of MgO- and FeO-free silicate melts, and S-free and FeNi metal-free systems. In addition, conclusions for Pt rest on an interpretation that the tiny metallic nuggets plaguing many such experiments, were formed upon quench. There is not agreement on this issue, and the general question of HSE solubility at high PT remains unresolved

Righter, K.↗
NASA NTRS2007

Crystal Field Effects and Siderophile Element Partitioning: Implications for Mars HSE Geochemistry

Analyses of martian (SNC) meteorites indicate that Pt abundances do not vary much compared to other highly siderophile elements (HSE). Therefore, Jones et al. [1] inferred that D(Pt) during basalt petrogenesis was of order unity. This inference was at odds with previously published experiments that gave a D(sub ol/liq) for Pt of approx. 0.01 [2]. Because olivine is likely to be an important constituent of any reasonable martian mantle, the implication of these findings is that minor minerals must have D(Pt) much greater than 1, which seemed improbable. However, not only did the SNC evidence point to a D(sub ol/liq) approx. equal to 1, but so did plots of D(sub ol/liq) vs. ionic radius (Onuma diagram). The ionic radius of Pt(2+) suggested that D(sub ol/liq) for Pt was of order unity, in agreement with the inferences from SNC meteorites. New experiments have failed to detect measurable Pt in olivine, even at high oxygen fugacities [3]. Therefore, some other parameter, other than ionic charge and radius, must hold sway during olivine liquid partitioning of Pt.

Jones, John H.↗
DOE OSTI2024

Enhancing the Carbon Monoxide Oxidation Performance through Surface Defect Enrichment of Ceria-Based Supports for Platinum Catalyst

Effective synthesis and application of single-atom catalysts on supports lacking enough defects remain a significant challenge in environmental catalysis. Herein, we present a universal defect-enrichment strategy to increase the surface defects of CeO 2 -based supports through H 2 reduction pretreatment. The Pt catalysts supported by defective CeO 2 -based supports, including CeO 2 , CeZrO x , and CeO 2 /Al 2 O 3 (CA), exhibit much higher Pt dispersion and CO oxidation activity upon reduction activation compared to their counterpart catalysts without defect enrichment. Specifically, Pt is present as embedded single atoms on the CA support with enriched surface defects (CA-HD) based on which the highly active catalyst showing embedded Pt clusters (Pt C ) with the bottom layer of Pt atoms substituting the Ce cations in the CeO 2 surface lattice can be obtained through reduction activation. Embedded PtC can better facilitate CO adsorption and promote O 2 activation at Pt C –CeO 2 interfaces, thereby contributing to the superior low-temperature CO oxidation activity of the Pt/CA-HD catalyst after activation.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Structural and Valence State Modification of Cobalt in CoPt Nanocatalysts in Redox Conditions

Platinum is the primary catalyst for many chemical reactions in the field of heterogeneous catalysis. However, platinum is both expensive and rare. Therefore, it is advantageous to combine Pt with another metal to reduce cost while also enhancing stability. To that end, Pt is often combined with Co to form Co-Pt nanocrystals. However, dynamical restructuring effects that occur during reaction in Co-Pt ensembles can impact catalytic properties. In this study, model Co 2 Pt 3 nanoparticles supported on carbon were characterized during a redox cycle with two in situ approaches, namely X-ray absorption spectroscopy (XAS) and scanning transmission electron microscopy (STEM) using a multimodal microreactor. The sample was exposed to temperatures up to 500 °C under H 2 , and then to O 2 at 300 °C. Irreversible segregation of Co in the Co-Pt particles was seen during redox cycling and substantial changes of the oxidation state of Co were observed. After the H 2 treatment, a fraction of Co could not be fully reduced and incorporated into a mixed Co-Pt phase. Re-oxidation of the sample increased Co segregation, and the segregated material had a different valence state than in the fresh, oxidized sample. Furthermore, this in situ study describes dynamical restructuring effects in CoPt nano-catalysts at the atomic scale that are crucial to understand to improve the design of catalysts used in major chemical processes.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on P2Pt5 by Materials Project

Pt5P2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Pt2- sites. In the first Pt2- site, Pt2- is bonded in a distorted water-like geometry to four equivalent Pt2- and two equivalent P5+ atoms. There are a spread of Pt–Pt bond distances ranging from 2.86–2.89 Å. There are one shorter (2.35 Å) and one longer (2.40 Å) Pt–P bond lengths. In the second Pt2- site, Pt2- is bonded in a 3-coordinate geometry to seven Pt2- and three equivalent P5+ atoms. There are a spread of Pt–Pt bond distances ranging from 2.80–2.92 Å. There are a spread of Pt–P bond distances ranging from 2.33–2.62 Å. In the third Pt2- site, Pt2- is bonded in a distorted L-shaped geometry to four equivalent Pt2- and two equivalent P5+ atoms. Both Pt–P bond lengths are 2.35 Å. P5+ is bonded in a 6-coordinate geometry to six Pt2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2AlPt by Materials Project

Li2PtAl crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded to four equivalent Li, six equivalent Pt, and four equivalent Al atoms to form distorted LiLi4Al4Pt6 tetrahedra that share corners with eighteen LiLi4Pt4 tetrahedra and faces with sixteen LiLi4Al4Pt6 tetrahedra. All Li–Li bond lengths are 2.62 Å. All Li–Pt bond lengths are 3.03 Å. All Li–Al bond lengths are 2.62 Å. In the second Li site, Li is bonded to four equivalent Li and four equivalent Pt atoms to form distorted LiLi4Pt4 tetrahedra that share corners with twelve equivalent LiLi4Al4Pt6 tetrahedra, edges with twelve equivalent LiLi4Pt4 tetrahedra, and faces with four equivalent LiLi4Al4Pt6 tetrahedra. All Li–Pt bond lengths are 2.62 Å. Pt is bonded in a distorted body-centered cubic geometry to ten Li and four equivalent Al atoms. All Pt–Al bond lengths are 2.62 Å. Al is bonded in a distorted body-centered cubic geometry to four equivalent Li and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sn3Pt2 by Materials Project

Pt2Sn3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pt is bonded in a distorted body-centered cubic geometry to one Pt and seven Sn atoms. The Pt–Pt bond length is 2.82 Å. There are a spread of Pt–Sn bond distances ranging from 2.72–2.91 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded to four equivalent Pt atoms to form a mixture of distorted edge and corner-sharing SnPt4 tetrahedra. In the second Sn site, Sn is bonded in a 6-coordinate geometry to six equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TiPt8 by Materials Project

Pt8Ti crystallizes in the tetragonal I4/mmm space group. The structure is one-dimensional and consists of two Pt8Ti ribbons oriented in the (0, 0, 1) direction. Ti4+ is bonded to twelve Pt+0.50- atoms to form face-sharing TiPt12 cuboctahedra. There are eight shorter (2.76 Å) and four longer (2.77 Å) Ti–Pt bond lengths. There are two inequivalent Pt+0.50- sites. In the first Pt+0.50- site, Pt+0.50- is bonded in a distorted L-shaped geometry to two equivalent Ti4+ atoms. In the second Pt+0.50- site, Pt+0.50- is bonded in a distorted single-bond geometry to one Ti4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2SbPt by Materials Project

Li2PtSb is Zintl Phase-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded to four equivalent Pt and six equivalent Sb atoms to form distorted LiSb6Pt4 tetrahedra that share corners with six equivalent LiSb6Pt4 tetrahedra, edges with twelve equivalent LiSb4Pt6 tetrahedra, and faces with sixteen LiSb6Pt4 tetrahedra. All Li–Pt bond lengths are 2.76 Å. All Li–Sb bond lengths are 3.18 Å. In the second Li site, Li is bonded to six equivalent Pt and four equivalent Sb atoms to form distorted LiSb4Pt6 tetrahedra that share corners with six equivalent LiSb4Pt6 tetrahedra, edges with twelve equivalent LiSb6Pt4 tetrahedra, and faces with sixteen LiSb6Pt4 tetrahedra. All Li–Pt bond lengths are 3.18 Å. All Li–Sb bond lengths are 2.76 Å. Pt is bonded in a 8-coordinate geometry to ten Li and four equivalent Sb atoms. All Pt–Sb bond lengths are 2.76 Å. Sb is bonded in a 8-coordinate geometry to ten Li and four equivalent Pt atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2PtO3 by Materials Project

Li2PtO3 is Caswellsilverite-like structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are eleven inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six LiO6 octahedra, edges with six LiO6 octahedra, and edges with six PtO6 octahedra. The corner-sharing octahedra tilt angles range from 5–6°. There are four shorter (2.15 Å) and two longer (2.16 Å) Li–O bond lengths. In the second Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.14–2.22 Å. In the third Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.14–2.22 Å. In the fourth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.11–2.22 Å. In the fifth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six LiO6 octahedra, edges with six LiO6 octahedra, and edges with six PtO6 octahedra. The corner-sharing octahedra tilt angles range from 5–6°. There are four shorter (2.15 Å) and two longer (2.16 Å) Li–O bond lengths. In the sixth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.14–2.22 Å. In the seventh Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are a spread of Li–O bond distances ranging from 2.11–2.22 Å. In the eighth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two LiO6 octahedra, corners with four PtO6 octahedra, edges with four PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.14–2.22 Å. In the ninth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six LiO6 octahedra, edges with six LiO6 octahedra, and edges with six equivalent PtO6 octahedra. The corner-sharing octahedra tilt angles range from 5–6°. There are four shorter (2.15 Å) and two longer (2.16 Å) Li–O bond lengths. In the tenth Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent PtO6 octahedra, edges with four equivalent PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–6°. There are a spread of Li–O bond distances ranging from 2.14–2.22 Å. In the eleventh Li1+ site, Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with two equivalent LiO6 octahedra, corners with four equivalent PtO6 octahedra, edges with four equivalent PtO6 octahedra, and edges with eight LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are two shorter (2.11 Å) and four longer (2.21 Å) Li–O bond lengths. There are five inequivalent Pt4+ sites. In the first Pt4+ site, Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent PtO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are two shorter (2.05 Å) and four longer (2.06 Å) Pt–O bond lengths. In the second Pt4+ site, Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent PtO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. All Pt–O bond lengths are 2.06 Å. In the third Pt4+ site, Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent PtO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are two shorter (2.05 Å) and four longer (2.06 Å) Pt–O bond lengths. In the fourth Pt4+ site, Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent PtO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. All Pt–O bond lengths are 2.06 Å. In the fifth Pt4+ site, Pt4+ is bonded to six O2- atoms to form PtO6 octahedra that share corners with six LiO6 octahedra, edges with three equivalent PtO6 octahedra, and edges with nine LiO6 octahedra. The corner-sharing octahedra tilt angles range from 4–5°. There are two shorter (2.05 Å) and four longer (2.06 Å) Pt–O bond lengths. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fourth O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fifth O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the sixth O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the seventh O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the eighth O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the ninth O2- site, O2- is bonded to four Li1+ and two Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the tenth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the eleventh O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the twelfth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the thirteenth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fourteenth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. In the fifteenth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–5°. The O–Li bond length is 2.15 Å. There are one shorter (2.05 Å) and one longer (2.06 Å) O–Pt bond lengths. In the sixteenth O2- site, O2- is bonded to four Li1+ and two equivalent Pt4+ atoms to form a mixture of edge and corner-sharing OLi4Pt2 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. The O–Li bond length is 2.16 Å. Both O–Pt bond lengths are 2.06 Å.

36 MATERIALS SCIENCE↗