bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screening Ruddlesden-Popper (n=1) Oxide Materials for Thermochemical Water Splitting By Density Functional Theory
Authors: Wilson George E. , Seymour Ieuan , Cavallaro Andrea , Skinner Stephen , Aguadero Ainara 
Published: July 2022

Thermochemical redox reactors store concentrated solar power by thermally inducing an oxygen deficiency within a metal oxide structure. The metal oxide’s affinity for reoxidation allows it to facilitate the splitting of H2O or CO2 to produce H2 or CO for syngas formation.[1] Typically, high temperatures (>1400 °C) are used to drive the reduction of the benchmark material, CeO2, [2] however there is motivation to lower this temperature and investigate new metal oxides capable of larger fuel productions. Perovskite materials have been thoroughly investigated due to their crystallographic stability and ability to accommodate relatively large oxygen deficiencies. Emery et al. [3] conducted a wide computational screening of this family of materials based on a few simple thermodynamic parameters originally proposed by Meredig and Wolverton. [4]
Herein, we extend these previous studies and investigate the A2BO4 Ruddlesden-Popper (RP) oxides family [5], layered perovskites, that have previously demonstrated fast redox kinetics and large oxygen storage as solid oxide fuel cell cathodes.[6] A combination of screening parameters based on charge neutrality, Goldschmidt tolerance and computed defect formation energy, identified 38 possible RP candidate materials. One of which - Ca2MnO4-δ – was taken forward to experimental testing due to its Earth abundant elements. The powder was synthesized via a modified Pechini method and thermal analysis experiments demonstrated thermally driven oxygen evolution from 800 to 1200 °C equating to a non-stoichiometry of δ=0.18. High-temperature X-ray diffraction alluded to the formation of a CaMn2O4 secondary phase above 1075 °C, therefore consequent thermochemical water splitting cycles were carried out at a maximum of 1000 °C. Oxidation under steam at 800 °C demonstrated good hydrogen production volumes, although gas production on further cycles was limited by particle sintering observed by scanning electron microscopy. Further investigations aim to understand and improve the cyclability and kinetics under different reaction temperatures and humidity. This study outlines, with experimental validation, how computational screening can be used to find future suitable RP candidates for thermochemical water splitting whose performance can be further improved with doping strategies and morphological adaptation.

References

[1] Scheffe J. R. and Steinfeld A., Materials Today, (2014), 17, 341-348
[2] Chueh W. C., et al., Science, (2010), 330, 1797–1801
[3] Emery A., et al., Chem. Mater. (2016), 28, 5621−5634
[4] Meredig B. and Wolverton C., Phys. Rev. B: Condens. Mater. Phys. (2009), 80, 245119.
[5] Ruddlesden S. N. and Popper P., Acta Crystallogr., (1957), 10, 538-539
[6] Ghorbani-Moghadam T., et al, Ceram. Int., (2018), 44, 21238–21248
Tandem Electrochemical Conversion of CO2 to Liquid Fuels and Chemical Feedstocks
Authors: Kang Mavis , Kolb Manuel , Calle-Vallejo Federico , Yeo Boon Siang Jason 
Published: July 2022

Increasing demand for energy has led to a high dependence on fossil fuels, which are limited and have been closely associated with major environmental issues such as groundwater pollution and imbalances in the carbon cycle. A more sustainable and cleaner method of producing chemicals and fuels is the electrochemical CO2 reduction reaction (CO2RR). When coupled with renewable electricity, CO2 can be converted to high energy density fuels and commodity chemicals, such as ethanol, propanol, and ethylene, in an environmentally friendly way.
Recently, the use of CO feedstocks, instead of CO2, was shown to enhance the selectivity toward multi-carbon products on copper-based electrocatalysts. Technoeconomic analyses have also demonstrated that CO can be produced from CO2RR cost-effectively. This has led to increased efforts in developing tandem electrocatalytic systems. However, state-of-the-art CO2-to-CO electrocatalysts are based on expensive noble metals such as Ag and Au, while earth-abundant Zn displays relatively poorer selectivity and activity. Herein, we show that oxide-derived Zn with high surface area can reduce CO2 to CO with a Faradaic efficiency of 86% and a partial current density (j
CO) of −201 mA cm-2. While oxygen vacancies were previously implicated for CO2RR to CO, we pinpointed by detailed experiments and density functional theory calculations that highly undercoordinated Zn sites provide even higher activity, in view of their nearly optimal *COOH adsorption energies. These findings indicate that suitably engineered ZnO-derived materials can potentially be an alternative to the more costly Ag and Au electrocatalysts, and that the main guideline for their design is to increase the undercoordination of the catalytic sites.
We also investigate the electrochemical CO reduction reaction (CORR) to liquid fuels and industrial feedstocks on copper-based and mixed copper-silver catalysts. To further enhance the CORR activity and product selectivities, a systematic optimization of the experimental environment, such as the use of various supports, catalyst binder and electrolytes, was done. We develop a set of experimental conditions for optimal CORR performance to value-added products.
Electro-Chemical-Mechanical Coupled Modeling of Oxygen Electrodes in Solid Oxide Electrolyzer Cells
Authors: Jin Xinfang , Jayapragasam Puvikkarasan , Wen Yeting , Huang Kevin 
Published: July 2022

Solid oxide electrolyzer cell (SOECs), which is an electrochemical device to split water with electricity to generate hydrogen, have received widespread attention for multi-day or seasonal energy storage to integrate variable renewable energy (VRE) into the grid [1]. Even though there have been tremendous material development and performance improvement of the technology in the past decade [2], challenges remain in understanding its degradation mechanism, especially the delamination of oxygen electrode/electrolyte interface [3-5]. Developing new oxygen electrodes which could decelerate the degradation and extend the stack lifetime beyond 60,000 hours at 1.5A/cm2 would significantly drive the stack price down to $100/kW and hydrogen cost down to $2/kg [6].
In the state-of-the-art SOECs, pure ionic conductor 8 mol% Y2O3 doped ZrO2 (YSZ) and Gadolinium-doped Ceria (GDC) are usually used as the dense electrolyte and the buffer layer; mixed electronic and ionic conductor (MIEC) La1-xSrxCo1-yFeyO3-d (LSCF) is widely used as the oxygen electrode [7]. Such cells still suffer from short lifetimes with current densities over 1A/cm2. To overcome the challenge, a bilayer oxygen electrode structure, consisting of a commercial LSCF-GDC porous backbone coated by a thin SrCo0.9Ta0.1O3-
d (SCT10) film (denoted as LSCF-SCT bilayer design), has been proposed and demonstrated with much higher performance compared to traditional LSCF electrode (single layer design) [8]. The new oxygen electrode has an inherently fast oxygen evolution reaction (OER) electrokinetics (or high oxygen evolution rate) and can mitigate the delamination problem by minimizing the accumulation of oxygen in oxygen evoluation reaction (OER) electrode lattice and thus chemical stresses.
In this study, based upon an Electro-Chemical-Mechanical coupled model, we will correlate the crack length at the oxygen electrode/electrolyte interface with the electrochemical performance of the cell, specifically the voltage-current curve (Fig.1a). We will use J-integral (Fig.1b) as the fracture criteria to evaluate the crack growth rate under different current densities and with different oxygen electrode designs. LSCF single layer design is the baseline of the study. The long-term performance improvement of LSCF-SCT bilayer design will be compared against the baseline and its degradation mechanism will be investigated. The model will also be validated by long-term overpotential testing data as a function of time under 1A/cm2. It will be used as an optimization tool to mitigate delamination and extend the cell lifetime under higher current densities.

Key Words: Electrolysis, Oxygen Electrode (OE), Delamination, Chemical Expansion, J integral, Crack Growth Rate

Figure 1
(Invited, Digital Presentation) Yet Another Symmetry Breaking in Electromechanical Materials
Authors: Pryds Nini 
Published: July 2022

The wide range of fascinating properties observed in complex oxide continue to attract great interest such as ferro-, piezo- and pyroelectricity. Several strategies have been employed to break the lattice symmetry and expand the range of functionalities. Electrostriction is a general property of all dielectrics and occurred when the deformation of a dielectric material is proportional to the square of the applied electric field. Recently, Gd2O3-doped CeO2 (CGO) has emerged as a new family of electrostriction materials with the maximum stress exceeding 500 MPa. To date, various efforts have been made to improve the strain output, such as stimulate by electric field, varying the temperature and aging the defects. However, materials that simultaneously satisfy the requirements of fast response, large strain and high energy density are still very rare. The development of materials with large dielectric breakdown strength, high dielectric constant and low elastic modulus is still challenging.
Heterostructure interfaces plays an important role by contributing to its unique structural and physical properties which result in symmetry breaking, electronic and/or atomic reconstruction(s) as well as strain gradients from which a wealth of new intriguing properties can emerge. Such richness arises from a strong interaction between the charge, orbital, spin, and lattice degrees of freedom.
Here, I will show how symmetry breaking offers extraordinary opportunities such as stabilizing phases which are otherwise not stable using highly coherent interfaces and enhancing the electromechanics with interfaces or inducing piezoelectricity in otherwise centrosymmetric system. In one example I will show the results obtained with a stack of ultrathin defective oxide single-crystal layers with stable phases and electrostriction properties exceeding any known system. Alternating layers of Gd2O3-doped CeO2 (CGO) and Er2O3-stabilized δ-Bi2O3 (ESB) were deposited on NdGaO3 substrates. The measured electrostriction coefficients found to follow a linear increase with the decrease of the number of interfaces. We have observed the highest electrostriction coefficient which surpasses any known electrostrictive materials, including the commercial relaxor ferroelectrics, such as PMN-PT. In another examples I will show our recent discovery illustrating the possibility to induce a large piezoelectric response in centrosymmetric oxides, i.e., in cubic fluorite oxides, Gd-doped CeO2-x. Surprisingly, the results show the generation of large low-frequency piezoelectric responses (d33 ~ 100,000 pm/V). Such a high piezoelectric response from intrinsically nonpiezoelectric materials has not been observed before in centrosymmetric materials.
This collection of possibilities offers unique opportunities for a wide range of rich world and new functionality of complex oxide and their interfaces.
(Invited) Operando Measurement of Heterogeneities in All-Solid-State Li Battery Electrodes
Authors: Gallaway Joshua W 
Published: July 2022

All-solid-state Li batteries are under intense research and development due to their potential to (a) replace flammable organic liquid electrolytes with solid materials, and (b) increase energy density by allowing Li metal anodes and resulting in a more compact battery.[1]Several types of Li+-conducting solid electrolytes are being studied, e.g. sulfides, oxides, phosphates, polymers, and various composites of these.[2] While polymers are very processable, they have low conductivities, generally <10-4 S/cm. Sulfides have high conductivities, >10-2 S/cm, but are unstable materials and require cells to be under high compression to get good cycling results.[3] Oxides and phosphates have good conductivity, but are hard and brittle, forming poor interfaces with electrode active materials. The ideal combination of solid electrolyte and active material remains elusive, but work continues.
An additional challenge looms for the design of all-solid-state electrodes, as reaction distributions in battery electrodes are often heterogeneous, resulting in uneven utilization of active materials.[4] Uneven reaction distributions are generally the result of an imbalance between electronic and ionic transport in the cell, but can also be caused by other resistances such as those introduced by insulating layers surrounding active materials. In this talk I will report our experimental results measuring heterogeneous phenomena in all-solid-state batteries. We have employed electrochemical impedance spectroscopy (EIS) as well as energy dispersive X-ray diffraction (EDXRD). EDXRD is a high-energy synchrotron technique that allows the interiors of batteries to be profiled in a tomographic way during battery operation. We use this to directly observe heterogeneous lithiation gradients across the thickness of cathodes in all-solid-state batteries. We will focus on cells with sulfide electrolytes, such as Li6PS5Cl and Li6.6Ge0.6Sb0.4S5I. Heterogeneous structural stability of the electrolyte itself will also be discussed.[5]

Acknowledgments

We acknowledge financial support from the National Science Foundation under Award Number CBET-ES-1924534.

References

[1] J. Janek and W. G. Zeier, "A solid future for battery development," Nat Energy, vol. 1, no. 9, pp. 1-4, 2016.
[2] J. C. Bachman et al., "Inorganic solid-state electrolytes for lithium batteries: mechanisms and properties governing ion conduction," Chem Rev, vol. 116, no. 1, pp. 140-162, 2016.
[3] Y. Kato et al., "High-power all-solid-state batteries using sulfide superionic conductors," (in English), Nat Energy, vol. 1, Mar 21 2016.
[4] J. S. Newman and C. W. Tobias, "Theoretical Analysis of Current Distribution in Porous Electrodes," J Electrochem Soc, vol. 109, no. 8, pp. C193-C193, 1962.
[5] X. Sun et al., "Operando EDXRD Study of All‐Solid‐State Lithium Batteries Coupling Thioantimonate Superionic Conductors with Metal Sulfide," Advanced Energy Materials, vol. 11, no. 3, p. 2002861, 2021.
One-Pot Synthesis of MnO2/Reduced Graphene Oxide Via Hydrothermal Routes for Supercapacitor Applications
Authors: Lee Hyejin Jin , Noor Navid , Gumeci Cenk , Higgins Drew 
Published: July 2022

Manganese dioxide (MnO2) is a promising supercapacitor electrode material due to its high theoretical capacitance, low cost and environmental compatibility. However, the electrochemical performance of MnO2 is often limited by low electrical conductivity of MnO2. The MnO2/carbon composites have been successfully demonstrated as an effective way to improve overall electrical conductivity of MnO2 based materials.
In this study, we report MnO2/reduced graphene oxide (rGO) composites for high performance supercapacitor applications. The MnO2/rGO composites exhibited 381F/g at a charge/discharge current density of 5 A/g, which was significantly higher as compared to that of pure MnO2 (140 F/g at a charge/discharge current density of 5 A/g). This result indicates that improved capacitance of the MnO2/rGO composites benefited from the incorporated rGO properties, such as high electrical conductivity and large surface area.
Facet-Dependent Selectivity of Cuprous Oxide/Silver Tandem Catalysts for Promoting C2H4 Production from Electrochemical CO2 Reduction
Authors: Geng Dongsheng , Dong Gang 
Published: July 2022

The over-exploitation of fossil fuels and the consequent increase of atmospheric CO2 concentration have aroused people's attention to energy and environmental issues.(1) In terms of reducing CO2 content, the electrocatalytic CO2 reduction reaction (CO2RR) can effectively solidify CO2 and convert it into high value-added chemicals. There are many CO2RR reduction products, including CO, HCOOH, C2H5OH, CH4,C2H4, etc.(2) However, in the CO2RR process, the hydrogen evolution reaction (HER) in the water phase has a lower reduction potential, making the CO2RR products less selective, which has become the most important problem restricting its practical application. Therefore, improving the selectivity and activity of CO2RR products has important research significance and practical application value.
In this work, a series of Cu2O/Ag nanocrystals (NCs) with different crystal faces were prepared by hydrothermal method. Specifically, cubic Cu2O (c-Cu2O) enclosed with {100} facets, rhombic dodecahedral Cu2O (d-Cu2O) enclosed with {110} facets, and octahedral Cu2O (o-Cu2O) enclosed with {111} facets, are mixed with Ag nanospheres to form c-Cu2O/Ag, d-Cu2O/Ag, and o-Cu2O/Ag bimetallic tandem catalysts. The catalysts can improve the high activity and selectivity of CO2RR to produce C2H4 product by adjusting different crystal faces. We can find from Figure 1 that o-Cu2O/Ag tandem catalyst exhibits an impressive Faradaic efficiency (66.8%) and partial current density (17.8 mA cm-2) for C2H4 product at -1.2 VRHE. This result provides a new strategy for improving the selectivity of CO2RR to produce C2+ products by adjusting the crystal facet engineering.

Figure 1. (a) SEM images of o-Cu2O/Ag, (b) LSV curves of three Cu2O/Ag catalysts in Ar and CO2-saturated 0.5 M KHCO3 solutions, (c) Partial current density of C2H4 formation on the three Cu2O/Ag catalysts at -1.2 V, (d) Faradaic efficiencies of C2H4 on the three Cu2O/Ag NCs.

Reference

[1] P. De Luna, C. Hahn, D. Higgins, S. A. Jaffer, T. F. Jaramillo and E. H. Sargent, Science, 364 (2019).
[2]Y. Zheng, A. Vasileff, X. Zhou, Y. Jiao, M. Jaroniec and S. Z. Qiao, J Am Chem Soc, 141, 7646 (2019).

Figure 1
Water-Assisted Electrochemical Ammonia Synthesis on Electrospun Cobalt-Molybdenum Carbide Composite
Authors: Chung Sunki , Ju Hyungkuk , Lee Jaeyoung 
Published: July 2022

The electrochemical synthesis of ammonia under ambient condition has attracted significant attention as an alternative route for green ammonia production. However, competing hydrogen evolution reaction (HER) hinders selective ammonia synthesis through electrochemical nitrogen reduction reaction (NRR). For the broad adoption of such technology in industries, it is essential to overcome poor selectivity of NRR by developing effective electrocatalysts and controlling the reactant at the interface between electrode and electrolyte.[1,2] In this study, we prepared cobalt-molybdenum carbide-carbon nanofiber via electrospinning method as a selective NRR catalyst. Furthermore, we reveal the relationship between water adsorption ability and NRR selectivity on biphasic catalyst using isotopic-labeling and in-situ analyses.

Reference

[1] Journal of Electroanalytical Chemistry
2021, 896, 115157.
[2] Journal of Energy Chemistry
2022, 67, 474–482.
Ex-Situ Investigation of Membrane Swelling in an Electrolyzer Using X-Ray Tomography
Authors: Hoppe Eugen , Holtwerth Sebastian , Müller Martin , Lehnert Werner 
Published: July 2022

In this contribution, we focus on the membrane swelling of a catalyst coated Nafion© 212 in the compound of a polymer electrolyte membrane electrolyzer. So far, the swelling of the catalyst coated membrane (CCM) is mostly investigated isolated from the surrounding components as porous transport layers (PTL) and the flow field plates[1-4]. To explore the swelling, ex-situ tests were carried out, using a special device [5] to control contact pressure and compression and computer tomography. This allowed the swelling of the CCM to be studied at different positions in the structure and at different compression pressures as well as the interaction of the different components. Figure 1 shows a comparison of the dry (a) and (c) and flooded (b) and (d) state of the CCM. The black lines indicate the surface of the CCM. In the flooded state, the thickness of the CCM increases by 20 % from about 50 µm to 60 µm, while the distance of the expanded metal sheets stays constant. This means, that the thickness increase of the CCM results in a decrease of at least one PTL thickness. One main goal of the experiment was to show, whether the swelling of the membrane is dependent or independent of the compression pressure and therefore may cause a different water uptake, which might give an explanation of the decreasing high frequency resistance with increasing pressure [4, 6].
[1] Ito, H., Maeda, T., Nakano, A., & Takenaka, H. (2011). Properties of Nafion membranes under PEM water electrolysis conditions. International journal of hydrogen energy, 36(17), 10527-10540
[2] Budinski, M. K., & Cook, A. (2010). Osmotic pressure of water in Nafion®. Tsinghua Science & Technology, 15(4), 385-390
[3] Kusoglu, A., Kienitz, B. L., & Weber, A. Z. (2011). Understanding the effects of compression and constraints on water uptake of fuel-cell membranes. Journal of the Electrochemical Society, 158(12), B1504
[4] Borgardt, E., Giesenberg, L., Reska, M., Müller, M., Wippermann, K., Langemann, M., Lehnert, W., & Stolten, D. (2019). Impact of clamping pressure and stress relaxation on the performance of different polymer electrolyte membrane water electrolysis cell designs. International journal of hydrogen energy, 44(42), 23556-23567
[5] Hoppe, E., Janßen, H., Müller, M., & Lehnert, W. (2021). The impact of flow field plate misalignment on the gas diffusion layer intrusion and performance of a high-temperature polymer electrolyte fuel cell. Journal of Power Sources, 501, 230036
[6] Stähler, M., Stähler, A., Scheepers, F., Carmo, M., Lehnert, W., & Stolten, D. (2020). Impact of porous transport layer compression on hydrogen permeation in PEM water electrolysis. International journal of hydrogen energy, 45(7), 4008-4014

Figure 1