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Materials Data on CuH14C4(NO2)4 by Materials Project

Cu(HCOO)2(CO(NH2)2)2(H2O)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of four hydrazinocarbinol molecules; four water molecules; and one Cu(HCOO)2 sheet oriented in the (0, 0, 1) direction. In the Cu(HCOO)2 sheet, Cu2+ is bonded in a distorted square co-planar geometry to four O2- atoms. There is two shorter (1.98 Å) and two longer (2.00 Å) Cu–O bond length. C3+ is bonded in a trigonal planar geometry to one H1+ and two O2- atoms. The C–H bond length is 1.10 Å. There is one shorter (1.27 Å) and one longer (1.28 Å) C–O bond length. H1+ is bonded in a single-bond geometry to one C3+ atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu2+ and one C3+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cu2+ and one C3+ atom.

36 MATERIALS SCIENCE↗

Copper Tantalate by a Sodium-Driven Flux-Mediated Synthesis for Photoelectrochemical CO 2 Reduction

Copper-tantalate, Cu 2 Ta 4 O 11 (CTO), shows significant promise as an efficient photocathode for multi-carbon compounds (C 2+ ) production through photoelectrochemical (PEC) CO 2 reduction, owing to its suitable energy bands and catalytic surface. However, synthesizing CTO poses a significant challenge due to its metastable nature and thermal instability. In this study, this challenge is addressed by employing a flux-mediated synthesis technique using a sodium-based flux to create sodium-doped CTO (Na-CTO) thin films, providing enhanced nucleation and stabilization for the CTO phase. To evaluate the PEC performance and catalytic properties of the films, copper(II) oxide (CuO) at the Na-CTO surface is selectively etched. The etched Na-CTO shows a lower dark current, with decreased contribution from photocorrosion, unlike the non-etched Na-CTO which has remaining CuO on the surface. Furthermore, Na-CTO exhibits 7.3-fold ethylene selectivity over hydrogen, thus highlighting its promising potential as a photocathode for C 2+ production through PEC CO 2 reduction.

copper tantalate↗

Production of C 2 /C 3 Oxygenates from Planar Copper Nitride-Derived Mesoporous Copper via Electrochemical Reduction of CO 2

Electrochemical reduction of CO 2 provides an opportunity to produce fuels and chemicals in a carbon-neutral manner, assuming that CO 2 can be captured from the atmosphere. To do so requires efficient, selective, and stable catalysts. In this study, we report a highly mesoporous metallic Cu catalyst prepared by electrochemical reduction of thermally nitrided Cu foil. Under aqueous saturated CO 2 reduction conditions, the Cu 3 N-derived Cu electrocatalyst produces virtually no CH 4 , very little CO, and exhibits a faradaic efficiency of 68% in C 2+ products (C 2 H 4 , C 2 H 5 OH, and C 3 H 7 OH) at a current density of ~18.5 mA cm –2 and a cathode potential of -1.0 V versus the reversible hydrogen electrode. Under these conditions, the catalyst produces more oxygenated products than hydrocarbons. We show that surface roughness is a good descriptor of catalytic performance. The roughest surface reached 98% CO utilization efficiency for C 2+ product formation from CO 2 reduction and the ratio of oxygenated to hydrocarbon products correlates with the degree of surface roughness. These effects of surface roughness are attributed to the high population of undercoordinated sites as well as a high pH environment within the mesopores and adjacent to the surface of the catalyst.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Constructing a square-like copper cluster to boost C–C coupling for CO 2 electroreduction to ethylene

The CO 2 electroreduction reaction (CO 2 ER) to ethylene (C 2 H 4 ) offers the dual promise of lowering CO 2 emission while storing energy from renewable electricity, for which the development of highly efficient electrocatalysts is of great significance. Herein, by means of density functional theory (DFT) computations, we designed an electrocatalyst for CO 2 -to-C 2 H 4 conversion by anchoring a Cu 5 cluster supported on a MoS 2 monolayer with an S monovacancy (Cu 5 @MoS 2 ). Our results revealed that one Cu atom of the Cu 5 cluster was embedded into the framework of the defective MoS 2 monolayer, while the other four Cu atoms form a square-like island over the substrate surface. Interestingly, the C–C coupling between two *CO species can easily occur on the unique square-like active site with a low kinetic barrier of 0.56 eV to form the key *C 2 O 2 intermediate, which can then be hydrogenated to the C 2 H 4 product with a very low limiting potential (–0.32 eV). Significantly, alkaline conditions (pH = 13) are beneficial to further promote C 2 H 4 synthesis. Finally, our work may offer a new avenue to precisely modulate the structures of Cu clusters for converting CO 2 into high-value target products.

30 DIRECT ENERGY CONVERSION↗

Highly Selective Electrocatalytic Reduction of CO 2 into Methane on Cu–Bi Nanoalloys

Methane (CH 4 ), the main component of natural gas, is one of the most valuable products facilitating energy storage via electricity conversion. However, the poor selectivity and high overpotential for CH 4 formation with metallic Cu catalysts prevent realistic applications. Introducing a second element to tune the electronic state of Cu has been widely used as an effective method to improve catalytic performance, but achieving high selectivity and activity toward CH 4 remains challenging. Here, we successfully synthesized Cu–Bi NPs, which exhibit a CH 4 Faradaic efficiency (FE) as high as 70.6% at -1.2 V versus reversible hydrogen electrode (RHE). The FE of Cu–Bi NPs has increased by approximately 25-fold compared with that of Cu NPs. DFT calculations showed that alloying Cu with Bi significantly decreases the formation energy of *COH formation, the rate-determining step, which explains the improved performance. Further analysis showed that Cu that has been partially oxidized because of electron withdrawal by Bi is the most possible active site.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Fundamental Interactions of Bimetallic Cu x Pd y ( x + y = 4) Clusters Supported on the α-WC(0001) Surface and Their Performance for CO 2 Adsorption and Dissociation

The tungsten carbide α-WC(0001) surface, an active system for the activation of H 2 and important hydrogenation processes involving unsaturated hydrocarbons, can serve as a support of bimetallic clusters to produce materials with unique catalytic properties, opening routes for a wide range of technical applications. In particular, Cu x Pd y clusters are of particular interest because they combine metals with different properties. A stochastic method was applied to obtain the geometry of Cu x Pd y (x + y = 4) bare clusters, evaluating thousands of possibilities to obtain stable structures, yielding one isomer for Cu 4 , Cu 2 Pd 2 , Cu 1 Pd 3 , and Pd 4 and two isomers for Cu 3 Pd 1 . These clusters were supported on C and W terminations of the tungsten carbide (0001) surface, exploring all of the binding possibilities. The adsorption energies on the C and W terminations are in the ranges from −2.51 to −3.02 eV and from −2.26 to −3.30 eV, respectively. The strongest and weakest binding was seen for monometallic Cu 4 and Pd 4 clusters on both C and W terminations, while the Cu-Pd bimetallics have intermediate adsorption energies but lack a clear trend in terms of composition. The location of Cu x Pd y clusters over the (0001) surface induces a decrease in the work function relative to the pristine surface, while the cluster-surface Bader charge transfer and variations in the partial density of states point to changes in the electronic structure of the carbide atoms upon binding of the metallic clusters. The d-band center of the Cu x Pd y deposited on WC(0001) indicates an intermediate reactivity among Cu(111) and Pd(111) surfaces, modulating the reactivity with small numbers of Cu and Pd atoms, i.e., atom economy in catalyst design. The likelihood of existence of the most stable Cu x Pd y (x + y = 4) clusters in the temperature range of 298-400 K is 100%. The composite Cu x Pd y /α-WC(0001) (x + y = 4), is a nontrivial system since 22 isomers are needed to completely describe its structural properties. Among the isomers, seven structures are necessary to represent Cu 3 Pd 1 /α-WC(0001), five for Pd 4 /α-WC(0001), two for Cu 4 /α-WC(0001), and four for Cu 2 Pd 2 /α-WC(0001) and Cu 1 Pd 3 /α-WC(0001). The large number of cluster isomers supported on the tungsten carbide surface opens the door for several applications in the heterogeneous catalysis of the Cu x Pd y /α-WC(0001) composite, with the possibility of modulating the geometric, electronic, and chemical properties according to a desired application. Test studies for the adsorption of CO 2 indicate that the Cu x Pd y /α-WC(0001) composites are highly active for the adsorption and decomposition of the molecule, with bimetallic and admetal-carbide interactions playing a key role in the binding performance. In conclusion, this high activity indicates that these systems should be useful as catalysts for the conversion of CO 2 to oxygenates or light alkanes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Sticking Coefficients of Fusion Reactor Impurities from Molecular Dynamics Simulations for the Design of Cryopumps

A cryopump can be utilized as an impurity removal component of a direct internal recirculation (DIR) system for the fusion fuel cycle. The DIR facilitates a low fuel inventory by continuously pumping unburnt fuel while removing impurities from the fusion exhaust stream. A cryopump can target multiple impurity species by maintaining a temperature lower than the gas triple-point temperature that promotes desublimation. The desublimation/condensation of gases in cryopumps can be characterized by the sticking coefficient, which is defined as the probability for a gas particle to stick to a (cryo-)surface upon collision. The sticking coefficient is one of the important design/operation parameters for cryopumps, and it depends on a variety of surface and gas properties. Here, in this study, molecular dynamics simulations were utilized to estimate the sticking coefficients of typical fusion gas impurity species N 2 , CO 2 , and CH 4 over a Cu surface for a range of gas temperatures and surface coverages. The molecular dynamics study showed that the sticking coefficients for gases decrease with an increase in gas temperature. The presence of a single full monolayer of condensate on the metallic surface showed an adverse effect on the sticking of gases; however the sticking improved with two full monolayers of condensate on the surface. The sticking of gases over the mixed condensate on a surface was more favorable than the condensate of the same species for N 2 and CH 4 , with an exception for CO 2 , which showed a decrease in sticking over the mixed condensate.

cryopump↗

Accurate Prediction of Voltage of Battery Electrode Materials Using Attention-Based Graph Neural Networks

Performing first-principles calculations to discover electrodes’ properties in the large chemical space is a challenging task. While machine learning (ML) has been applied to effectively accelerate those discoveries, most of the applied methods ignore the materials’ spatial information and only use predefined features: based only on chemical compositions. Here, we propose two attention-based graph convolutional neural network techniques to learn the average voltage of electrodes. Our proposed methods, which combine both atomic composition and atomic coordinates in 3D-space, improve the accuracy in voltage prediction significantly when compared to composition-based ML models. The first model directly learns the chemical reaction of electrodes and metal ions to predict their average voltage, whereas the second model combines electrodes’ ML predicted formation energy (E form ) to compute their average voltage. Our E form -based model demonstrates improved accuracy in transferability from our subset of learned Li ions to Na ions. Moreover, we predicted the theoretical voltage of 10 Na x MPO 4 F (M = Ti, Cr, Fe, Cu, Mn, Co, and Ni) fluorophosphate battery frameworks, which are unavailable in the Material Project database. It could be shown that we can expect average voltages higher than 3.1 V from those Na battery frameworks except from the NaTiPO 4 F and TiPO 4 F pair of electrodes, which offer an average voltage of 1.32 V.

25 ENERGY STORAGE↗

A Facile Potential Hold Method for Fostering an Inorganic Solid‐Electrolyte Interphase for Anode‐Free Lithium‐Metal Batteries

Abstract Anode‐free lithium batteries are regarded as an ultimate form of high‐energy‐density lithium‐ion batteries. Unfortunately, irreversible lithium loss during cycling plays a major role in degrading the overall cell performance in the anode‐free configuration. To alleviate the deterioration, building a robust solid‐electrolyte interface on an anode current collector is an indispensable requirement. Here, we present a facile in‐situ electrochemical method of a potential hold during the first charge to guide more salt‐derived (less solvent‐derived) decomposition on the anode interface. We show the distinctive decomposition potential of lithium salts and ether/carbonate solvents, where the Li‐solvation structures with salt contact‐ion‐pairs preferentially decompose to form LiF‐rich and less organic components, leading to enhanced lithium Coulombic efficiency in Li||Cu cells as well as mitigating the capacity fade of Cu||LiFePO 4 and Cu||LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells.

Shin, Woochul↗

A Facile Potential Hold Method for Fostering an Inorganic Solid-Electrolyte Interphase for Anode-Free Lithium-Metal Batteries

Anode-free lithium batteries are regarded as an ultimate form of high-energy-density lithium-ion batteries. Unfortunately, irreversible lithium loss during cycling plays a major role in degrading the overall cell performance in the anode-free configuration. To alleviate the deterioration, building a robust solid-electrolyte interface on an anode current collector is an indispensable requirement. Here, we present a facile in-situ electrochemical method of a potential hold during the first charge to guide more salt-derived (less solvent-derived) decomposition on the anode interface. Here we show the distinctive decomposition potential of lithium salts and ether/carbonate solvents, where the Li-solvation structures with salt contact-ion-pairs preferentially decompose to form LiF-rich and less organic components, leading to enhanced lithium Coulombic efficiency in Li||Cu cells as well as mitigating the capacity fade of Cu||LiFePO 4 and Cu||LiNi 0.8 Mn 0.1 Co 0.1 O 2 cells.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Magnetic Texture in Insulating Single Crystal High Entropy Oxide Spinel Films

Magnetic insulators are important materials for a range of next-generation memory and spintronic applications. Structural constraints in this class of devices generally require a clean heterointerface that allows effective magnetic coupling between the insulating layer and the conducting layer. However, there are relatively few examples of magnetic insulators that can be synthesized with surface qualities that would allow these smooth interfaces and precisely tuned interfacial magnetic exchange coupling, which might be applicable at room temperature. In this work, we demonstrate an example of how the configurational complexity in the magnetic insulator layer can be used to realize these properties. The entropy-assisted synthesis is used to create single-crystal (Mg 0.2 Ni 0.2 Fe 0.2 Co 0.2 Cu 0.2 )Fe 2 O 4 films on substrates spanning a range of strain states. These films show smooth surfaces, high resistivity, and strong magnetic responses at room temperature. Furthermore, local and global magnetic measurements further demonstrate how strain can be used to manipulate the magnetic texture and anisotropy. These findings provide insight into how precise magnetic responses can be designed using compositionally complex materials that may find application in next-generation magnetic devices.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

First-Principles Calculations of the Structural, Electronic, Optical, and Mechanical Properties of 21 Pyrophosphate Crystals

Pyrophosphate crystals have a wide array of applications in industrial and biomedical fields. However, fundamental understanding of their electronic structure, optical, and mechanical properties is still scattered and incomplete. In the present research, we report a comprehensive theoretical investigation of 21 pyrophosphates A 2 M (H 2 P 2 O 7 ) 2 •2H 2 O with either triclinic or orthorhombic crystal structure. The molecule H 2 P 2 O 7 is the dominant molecular unit, whereas A = (K, Rb, NH 4 , Tl), M = (Zn, Cu, Mg, Ni, Co, Mn), and H 2 O stand for the cation elements, transition metals, and the water molecules, respectively. The electronic structure, interatomic bonding, partial charge distribution, optical properties, and mechanical properties are investigated by first-principles calculations based on density functional theory (DFT). Most of these 21 crystals are theoretically investigated for the first time. The calculated results show a complex interplay between A, M, H 2 P 2 O 7 , and H 2 O, resulting in either metallic, half-metallic, or semi-conducting characteristics. The novel concept of total bond order density (TBOD) is used as a single quantum mechanical metric to characterize the internal cohesion of these crystals to correlate with the calculated properties, especially the mechanical properties. This work provides a large database for pyrophosphate crystals and a road map for potential applications of a wider variety of phosphates.

36 MATERIALS SCIENCE↗

Sub-Nanometer Nanoclusters of Copper Atop Single-Atom Copper Moieties toward Electrochemical CO 2 Hydrogenation to Methane

The electrochemical CO 2 reduction (eCO 2 R) offers a compelling route for converting CO 2 into value-added fuels and chemicals. Among CO 2 -derived products, methane (CH 4 ) occupies a distinct position, serving both as a key intermediate for emerging cascade electro-oxidation to oxygenates and as a strategically important extraterrestrial fuel that can be generated in situ from off-planet CO 2 resources. Although Cu-based catalysts capable of selectively producing CH 4 have been reported, they seldom sustain high selectivity at practically relevant current densities. Here, we created a single-step co-pyrolysis strategy toward generating and anchoring Cu sub-nanometer clusters (Cu SNC ) atop Cu-N x single-atom (SA) motifs embedded within N-doped carbon (NC), with controllable nanostructures through tuning of the synthesis parameters. Complementary spectroscopic analyses and density functional theory (DFT) calculations help reveal a structure−activity correlation that could guide the catalyst design. The Cu SNC @NC sample synthesized at 550 °C pyrolysis temperature (best described and modeled as Cu 3 -CuN 4 domains) represents the most effective combination of cluster size, metal-nitrogen coordination, and adsorption energetics needed to selectively promote CH 4 generation versus other eCO 2 R products. Incorporating pulsed electrolysis and hydrophobicity-modulated transport tuning at the triple-phase boundary (TPB) further enhanced CH 4 production achieving a partial CH 4 current density of ∼321 mA cm −2 , 53% Faradaic efficiency (FECH 4 ), and less than 4% combined FE for other eCO 2 R products, simplifying downstream CH 4 purification or upgrading. This work establishes generalizable principles for controlling Cu cluster atomicity and metal−nitrogen coordination, both of which are recognized determinants of CH 4 -efficient eCO 2 R.

CH4 production↗

Materials Data on Al7CoCu2 by Materials Project

Al7CoCu2 crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. Co is bonded in a 9-coordinate geometry to nine Al atoms. There are a spread of Co–Al bond distances ranging from 2.44–2.49 Å. Cu is bonded in a 10-coordinate geometry to two equivalent Cu and eight Al atoms. Both Cu–Cu bond lengths are 2.55 Å. There are a spread of Cu–Al bond distances ranging from 2.54–2.66 Å. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 1-coordinate geometry to one Co and four equivalent Cu atoms. In the second Al site, Al is bonded in a 2-coordinate geometry to two equivalent Co atoms. In the third Al site, Al is bonded in a 4-coordinate geometry to one Co and three equivalent Cu atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ba4Sr4Co3(CuO4)5 by Materials Project

Ba4Sr4Co3(CuO4)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are sixteen inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.50 Å. The Ba–Cu bond length is 2.57 Å. There are a spread of Ba–O bond distances ranging from 2.43–3.08 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to two Cu+2.40+ and seven O2- atoms. There are one shorter (2.37 Å) and one longer (2.53 Å) Ba–Cu bond lengths. There are a spread of Ba–O bond distances ranging from 2.30–3.18 Å. In the third Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.46 Å. The Ba–Cu bond length is 2.55 Å. There are a spread of Ba–O bond distances ranging from 2.40–3.06 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.53 Å. The Ba–Cu bond length is 2.49 Å. There are a spread of Ba–O bond distances ranging from 2.48–3.12 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.51 Å. The Ba–Cu bond length is 2.53 Å. There are a spread of Ba–O bond distances ranging from 2.44–3.08 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 1-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.47 Å. The Ba–Cu bond length is 2.52 Å. There are a spread of Ba–O bond distances ranging from 2.27–3.11 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.36 Å. The Ba–Cu bond length is 2.57 Å. There are a spread of Ba–O bond distances ranging from 2.33–3.10 Å. In the eighth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.44 Å. The Ba–Cu bond length is 2.51 Å. There are a spread of Ba–O bond distances ranging from 2.36–3.17 Å. In the ninth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.56 Å. The Ba–Cu bond length is 2.54 Å. There are a spread of Ba–O bond distances ranging from 2.44–3.22 Å. In the tenth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.46 Å. The Ba–Cu bond length is 2.59 Å. There are a spread of Ba–O bond distances ranging from 2.41–3.12 Å. In the eleventh Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to two Cu+2.40+ and seven O2- atoms. There are one shorter (2.46 Å) and one longer (2.55 Å) Ba–Cu bond lengths. There are a spread of Ba–O bond distances ranging from 2.46–3.13 Å. In the twelfth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.55 Å. The Ba–Cu bond length is 2.51 Å. There are a spread of Ba–O bond distances ranging from 2.45–3.15 Å. In the thirteenth Ba2+ site, Ba2+ is bonded in a 1-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Ba–Co bond length is 2.47 Å. The Ba–Cu bond length is 2.48 Å. There are a spread of Ba–O bond distances ranging from 2.27–3.01 Å. In the fourteenth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.43 Å. The Ba–Cu bond length is 2.53 Å. There are a spread of Ba–O bond distances ranging from 2.38–3.10 Å. In the fifteenth Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Ba–Co bond length is 2.44 Å. The Ba–Cu bond length is 2.48 Å. There are a spread of Ba–O bond distances ranging from 2.30–3.08 Å. In the sixteenth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Ba–Co bond length is 2.39 Å. The Ba–Cu bond length is 2.48 Å. There are a spread of Ba–O bond distances ranging from 2.37–3.09 Å. There are sixteen inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to two Cu+2.40+ and seven O2- atoms. There are one shorter (2.37 Å) and one longer (2.48 Å) Sr–Cu bond lengths. There are a spread of Sr–O bond distances ranging from 2.17–2.97 Å. In the second Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to one Cu+2.40+ and five O2- atoms. The Sr–Cu bond length is 2.44 Å. There are a spread of Sr–O bond distances ranging from 2.13–2.53 Å. In the third Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Sr–Co bond length is 2.36 Å. The Sr–Cu bond length is 2.52 Å. There are a spread of Sr–O bond distances ranging from 2.14–2.99 Å. In the fourth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to one Co4+, one Cu+2.40+, and five O2- atoms. The Sr–Co bond length is 2.38 Å. The Sr–Cu bond length is 2.51 Å. There are a spread of Sr–O bond distances ranging from 2.14–2.67 Å. In the fifth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Sr–Co bond length is 2.35 Å. The Sr–Cu bond length is 2.58 Å. There are a spread of Sr–O bond distances ranging from 2.23–3.15 Å. In the sixth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to two Cu+2.40+ and seven O2- atoms. There are one shorter (2.40 Å) and one longer (2.54 Å) Sr–Cu bond lengths. There are a spread of Sr–O bond distances ranging from 2.20–3.15 Å. In the seventh Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to one Cu+2.40+ and four O2- atoms. The Sr–Cu bond length is 2.51 Å. There are a spread of Sr–O bond distances ranging from 2.14–2.60 Å. In the eighth Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Sr–Co bond length is 2.34 Å. The Sr–Cu bond length is 2.56 Å. There are a spread of Sr–O bond distances ranging from 2.26–3.03 Å. In the ninth Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to one Co4+, one Cu+2.40+, and seven O2- atoms. The Sr–Co bond length is 2.35 Å. The Sr–Cu bond length is 2.52 Å. There are a spread of Sr–O bond distances ranging from 2.14–3.07 Å. In the tenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Sr–Co bond length is 2.33 Å. The Sr–Cu bond length is 2.56 Å. There are a spread of Sr–O bond distances ranging from 2.21–3.03 Å. In the eleventh Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to two Cu+2.40+ and seven O2- atoms. There are one shorter (2.37 Å) and one longer (2.49 Å) Sr–Cu bond lengths. There are a spread of Sr–O bond distances ranging from 2.15–3.13 Å. In the twelfth Sr2+ site, Sr2+ is bonded in a 1-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Sr–Co bond length is 2.35 Å. The Sr–Cu bond length is 2.52 Å. There are a spread of Sr–O bond distances ranging from 2.12–3.00 Å. In the thirteenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to one Cu+2.40+ and four O2- atoms. The Sr–Cu bond length is 2.58 Å. There are a spread of Sr–O bond distances ranging from 2.11–2.58 Å. In the fourteenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to one Co4+, one Cu+2.40+, and six O2- atoms. The Sr–Co bond length is 2.40 Å. The Sr–Cu bond length is 2.62 Å. There are a spread of Sr–O bond distances ranging from 2.20–3.00 Å. In the fifteenth Sr2+ site, Sr2+ is bonded in a 8-coordinate geometry to two Cu+2.40+ and six O2- atoms. There are one shorter (2.37 Å) and one longer (2.53 Å) Sr–Cu bond lengths. There are a spread of Sr–O bond distances ranging from 2.14–2.99 Å. In the sixteenth Sr2+ site, Sr2+ is bonded in a 7-coordinate geometry to two Cu+2.40+ and five O2- atoms. There are one shorter (2.32 Å) and one longer (2.63 Å) Sr–Cu bond lengths. There are a spread of Sr–O bond distances ranging from 2.22–2.91 Å. There are twelve inequivalent Co4+ sites. In the first Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and five O2- atoms. There are a spread of Co–O bond distances ranging from 1.82–2.59 Å. In the second Co4+ site, Co4+ is bonded in a 3-coordinate geometry to two Ba2+ and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.83–2.30 Å. In the third Co4+ site, Co4+ is bonded in a 4-coordinate geometry to two Ba2+ and five O2- atoms. There are a spread of Co–O bond distances ranging from 1.81–2.54 Å. In the fourth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Ba2+ and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.80–2.20 Å. In the fifth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and five O2- atoms. There are a spread of Co–O bond distances ranging from 1.80–2.54 Å. In the sixth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to two Sr2+ and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.76–2.19 Å. In the seventh Co4+ site, Co4+ is bonded in a 4-coordinate geometry to two Ba2+ and five O2- atoms. There are a spread of Co–O bond distances ranging from 1.77–2.52 Å. In the eighth Co4+ site, Co4+ is bonded in a 3-coordinate geometry to one Ba2+, one Sr2+, and five O2- atoms. There are a spread of Co–O bond distances ranging from 1.77–2.46 Å. In the ninth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.73–2.15 Å. In the tenth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Sr2+ and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.78–2.22 Å. In the eleventh Co4+ site, Co4+ is bonded in a 4-coordinate geometry to two Ba2+ and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.81–2.14 Å. In the twelfth Co4+ site, Co4+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Co–O bond distances ranging from 1.80–2.25 Å. There are twenty inequivalent Cu+2.40+ sites. In the first Cu+2.40+ site, Cu+2.40+ is bonded in a 4-coordinate geometry to one Ba2+ and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–2.13 Å. In the second Cu+2.40+ site, Cu+2.40+ is bonded in a 4-coordinate geometry to two Sr2+ and six O2- atoms. There are a spread of Cu–O bond distances ranging from 1.98–2.61 Å. In the third Cu+2.40+ site, Cu+2.40+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.97–2.11 Å. In the fourth Cu+2.40+ site, Cu+2.40+ is bonded in a distorted square co-planar geometry to two Sr2+ and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–2.12 Å. In the fifth Cu+2.40+ site, Cu+2.40+ is bonded in a 6-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.89–2.27 Å. In the sixth Cu+2.40+ site, Cu+2.40+ is bonded in a 6-coordinate geometry to two Sr2+ and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.94–2.24 Å. In the seventh Cu+2.40+ site, Cu+2.40+ is bonded in a 2-coordinate geometry to two Ba2+ and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.85–2.27 Å. In the eighth Cu+2.40+ site, Cu+2.40+ is bonded in a 2-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.75–2.35 Å. In the ninth Cu+2.40+ site, Cu+2.40+ is bonded in a 6-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.90–2.25 Å. In the tenth Cu+2.40+ site, Cu+2.40+ is bonded in a 4-coordinate geometry to one Ba2+, one Sr2+, and four O2- atoms. There are a spread of Cu–O bond distances ranging from 1.99–2.29 Å. In the eleventh Cu+2.40+ site,

36 MATERIALS SCIENCE↗

Design guidance for ferrites: Insights from density functional theory on magnetic properties

A grand challenge in materials research is identifying the relationship between composition and performance. Herein, we explore this relationship for magnetic properties, specifically magnetic saturation (M s ) and magnetocrystalline anisotropy energy (K) of ferrites. Ferrites are materials derived from magnetite (chemical formula = Fe 3 O 4 ) that comprise metallic elements such as Fe, Mn, Ni, Co, Cu and Zn. Experimentally, synthesizing and characterizing ferrites is time consuming. Further, selection of compositions to achieve particular magnetic properties currently relies on intuition. To address this, in this work, density functional theory (DFT) is used to predict M s and K for 571 ferrite structures. These structures are primarily double-substituted non-stoichiometric ferrites with formulae M1 x M2 y Fe 3–x–y O 4 , where M1 and M2 can be Mn, Ni, Co, Cu and/or Zn and 0 ≤ x ≤ 1 and y = 1–x. Calculated magnetic properties for the structures in this study vary from 0.04 × 10 5 to 9.6 × 10 5 A m −1 for M s and from 0.02 × 10 5 to 14.08 × 10 5 J m −3 for K. All structures are made publicly available in a FAIR database.

36 MATERIALS SCIENCE↗

An AFM study of Zn/MnO 2 Co-deposition (ORISE Internship Report)

With the growing demand for rechargeable batteries, the aqueous Zn-ion battery has shown promise as a cheaper and safer alternative to modern Li-ion batteries. Meanwhile, for developing batteries with optimal charge transfer, electrodes with interpenetrating geometries have been explored to minimize the distance traveled by ions in the electrolyte. Creating a Zn-ion battery with interpenetrating electrodes may allow for more efficient cycling, but requires the co-deposition of anode and cathode materials. Because of the highly sensitive nature of electrodeposition, the presence of additional ions may have an impact on the success and homogeneity of cathode/anode deposition, possibly preventing the proper function of an interpenetrating Zn battery. This study examined the effects of added ions on Zn deposition through in situ Atomic Force Microscopy with the goal of determining whether the co-deposition of Zn and MnO 2 is a viable option for electrodes with interpenetrating geometries. Solutions of 1M ZnSO 4 and 1M ZnSO 4 + 0.1M C 4 H 6 MnO 4 were made to simulate normal and co-deposition conditions. Layers of Zn were electrodeposited onto a Cu microelectrode at a current density of 10mA cm -2 with intermittent AFM imaging after 50 deposited monolayers. The presence of manganese acetate (C 4 H 6 MnO 4 ) was found to decrease Zn nucleation size on the Cu UME, suggesting the presence of C 4 H 6 MnO 4 would not negatively impact the co-deposition of Zn and MnO 2 .

25 ENERGY STORAGE↗

Materials Data on BaSr7Co4(CuO6)4 by Materials Project

BaSr7Co4(CuO6)4 is (Cubic) Perovskite-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ba is bonded to twelve O atoms to form BaO12 cuboctahedra that share corners with twelve equivalent SrO12 cuboctahedra, faces with six equivalent SrO12 cuboctahedra, faces with four CoO6 octahedra, and faces with four CuO6 octahedra. There are three shorter (2.81 Å) and nine longer (2.82 Å) Ba–O bond lengths. There are three inequivalent Sr sites. In the first Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with twelve SrO12 cuboctahedra, faces with two equivalent BaO12 cuboctahedra, faces with four equivalent SrO12 cuboctahedra, faces with four CoO6 octahedra, and faces with four CuO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.74–2.78 Å. In the second Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with four equivalent BaO12 cuboctahedra, corners with eight equivalent SrO12 cuboctahedra, faces with six SrO12 cuboctahedra, faces with four CoO6 octahedra, and faces with four CuO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.66–2.78 Å. In the third Sr site, Sr is bonded to twelve O atoms to form SrO12 cuboctahedra that share corners with twelve equivalent SrO12 cuboctahedra, faces with six equivalent SrO12 cuboctahedra, faces with four CoO6 octahedra, and faces with four CuO6 octahedra. There are a spread of Sr–O bond distances ranging from 2.72–2.76 Å. There are two inequivalent Co sites. In the first Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with two equivalent CoO6 octahedra, corners with four equivalent CuO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Co–O bond distances ranging from 1.91–1.99 Å. In the second Co site, Co is bonded to six O atoms to form CoO6 octahedra that share corners with six equivalent CoO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 0–3°. There is three shorter (1.90 Å) and three longer (1.92 Å) Co–O bond length. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded to six O atoms to form CuO6 octahedra that share corners with six equivalent CuO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–4°. There is three shorter (1.95 Å) and three longer (1.96 Å) Cu–O bond length. In the second Cu site, Cu is bonded to six O atoms to form CuO6 octahedra that share corners with two equivalent CuO6 octahedra, corners with four equivalent CoO6 octahedra, a faceface with one BaO12 cuboctahedra, and faces with seven SrO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Cu–O bond distances ranging from 1.94–1.99 Å. There are six inequivalent O sites. In the first O site, O is bonded to one Ba, three Sr, and two Cu atoms to form distorted OBaSr3Cu2 octahedra that share corners with fourteen OBaSr3CoCu octahedra, edges with four equivalent OBaSr3CoCu octahedra, and faces with six OBaSr3Cu2 octahedra. The corner-sharing octahedra tilt angles range from 1–61°. In the second O site, O is bonded to one Ba, three Sr, one Co, and one Cu atom to form a mixture of distorted edge, corner, and face-sharing OBaSr3CoCu octahedra. The corner-sharing octahedra tilt angles range from 2–63°. In the third O site, O is bonded to one Ba, three Sr, and two Co atoms to form distorted OBaSr3Co2 octahedra that share corners with sixteen OBaSr3Cu2 octahedra, edges with four equivalent OBaSr3CoCu octahedra, and faces with four OBaSr3CoCu octahedra. The corner-sharing octahedra tilt angles range from 1–63°. In the fourth O site, O is bonded to four Sr and two Cu atoms to form a mixture of distorted corner and face-sharing OSr4Cu2 octahedra. The corner-sharing octahedra tilt angles range from 2–60°. In the fifth O site, O is bonded in a distorted linear geometry to four Sr, one Co, and one Cu atom. In the sixth O site, O is bonded in a distorted linear geometry to four Sr and two Co atoms.

36 MATERIALS SCIENCE↗