bluuebunny/crossref_metadata_2025 huggingface dataset:
Charge Transfer Donor-Acceptor Guests Confined within Metal-Organic Framework Crystals
Authors: Shivanna Mohana , Allendorf Mark D. , Abou Taka Ali , Schrader Paul E , Ramasesha Krupa , McCaslin Laura M , Stavila Vitalie
Published: December 2024

Organic donor-acceptor (D-A) co-crystals have emerged as a promising class of semiconductors for photovoltaic applications.1,2 These co-crystals, which are packed through π-stacking interactions, can form charge transfer (CT) excitons within donor-acceptor pairs. These materials can exhibit unique and rare properties such as ambipolar charge transport, room-temperature ferroelectricity, and non-linear optical properties. Confinement of such D-A pairs within crystalline porous host materials such as metal-organic materials (MOFs)3 has rarely been studied. This approach can improve energy and charge transfer interactions by constraining their interaction and minimizing nonradiative energy transfer. Additionally, the formation of D-A pairs as dimers or a polymeric phase without altering the CT interactions can be controlled; band gap tunability is also possible. We hypothesize that confining D-A pairs within a porous network will also enhance the exciton lifetime compared to its dimer state in a crystal or in solution. In 2014, we reported an example of successful confinement of dihexyl-sexithiophene (acceptor) and [6,6]-phenyl-C61-butyric acid methyl ester (donor) molecules within the pores of MOF-177.4 In the present work, we focused on different sets of D-A pairs to provide direct structural insights, such as the location within the pore, host-guest interactions, and guest-guest orientation. For this purpose, we dissolved naphthalene-TCNQ or pyrene-TCNQ in dichloromethane (DCM) at a 1:1 ratio and soaked MOF-177 crystals in the solution for 3 days. UV-Vis spectroscopy reveals the difference in the absorption bands of the isolated molecules vs. D-A pairs in MOF pores. To confirm the presence of guest species inside the MOF and to determine the donor vs. acceptor ratio we obtained nuclear magnetic resonance (NMR) spectra. Interestingly, our preliminary results confirm that both naphthalene-TCNQ and pyrene-TCNQ pairs were accommodated inside the MOF but in different stoichiometric ratios. We also collected single crystal X-ray diffraction of the MOF crystals after being soaked after infiltration with D-A pairs. Structural refinement is underway to determine their position and interactions. Our approach provides new mechanistic insights and also produces new benchmark materials with long exciton lifetimes, which can be utilized to advance current photonic technologies.

References

Abou Taka, J. E. Reynolds Iii, N. C. Cole-Filipiak, M. Shivanna, C. J. Yu, P. L. Feng, et al. Phys. Chem. Chem. Phys.
2023, 25, 27065.

Sun, Y. Wang, F. Yang, X. Zhang and W. Hu. Adv. Mater.
2019, 31, 1902328.

Shivanna, Q.-Y. Yang, A. Bajpai, E. Patyk-Kazmierczak and M. J. Zaworotko, Nat. Commun. 2018, 9, 3080.

K. Leong, M. E. Foster, B. M. Wong, E. D. Spoerke, D. Van Gough, J. C. Deaton, et al.
J. Mat. Chem. A
2014, 2, 3389.
High-Performance Electrochromic Devices Composed of Niobium Tungsten Oxide Films
Authors: Kang Kwang-Mo , Nah Yoon-Chae
Published: December 2024

Electrochromic technology plays a pivotal role in various industries, offering significant benefits in energy efficiency and sustainability. By efficiently modulating sunlight, it reduces dependence on traditional climate control systems, thus decreasing overall energy consumption. Among electrochromic materials, tungsten oxide (WO3) is highly favored for its outstanding stability and superior optical modulation amplitude. However, the escalating demands of commercial applications necessitate enhancements in electrochromic performance, achievable through doping or composite designs. This study investigates the electrochromic characteristics of novel niobium tungsten oxide (Nb18W16O93) thin films, employing a gel electrolyte and examining their structural, optical, and electrochemical attributes. Compared to pure WO3, the Nb18W16O93-based electrochromic device exhibited a significant optical modulation of 55.1% in the visible spectrum and 31.3% in the near-infrared region. The gel-based device not only provides safety benefits over liquid electrolytes by mitigating leakage risks but also features rapid switching response times, with a coloration duration of 3.9 s and a bleaching interval of 3.6 s. Moreover, the device showcases exceptional long-term stability, retaining a ΔT of nearly 72% after 10,000 cycles.
A Library of High-Entropy-Alloy Nanocrystals with Controlled Facets for Catalysis
Authors: Yang Tung-Han
Published: December 2024

High-entropy-alloy (HEA) nanocrystals consisting of a minimum of five elements have recently emerged as a versatile family of catalysts due to immense chemical space and tunability. However, there are no effective strategies for synthesizing libraries of HEA nanocrystals with controlled surface atomic structures of exposed facets for boosting catalytic performance. Due to the distinct nucleation and growth kinetics of constituent metals and their distinctive crystal structures, it is incredibly challenging to confine five or more different metal species situated on the nanocrystal surface with a specific arrangement but also in a high-entropy random mixing state. Here we present a straightforward strategy to craft a library of facet-controlled HEA nanocrystals with up to ten dissimilar metallic elements by solution-phase layer-by-layer epitaxial growth, enabling the design of 638 distinct catalysts with 5 to 10 elements in equimolar ratios. The subnanometer-thick solid-solution HEA atomic layers can be deposited epitaxially on nanocrystal seeds with {100} and {111} facets, thus achieving HEA shells with square and hexagonal atomic arrangements, respectively. The hollow HEA nanocages with ultrathin walls along a specific direction can be further fabricated via post-synthetic chemical etching. Three facet-dependent catalytic actives of HEA nanocrystals are discovered in electrocatalysis and photocatalysis, and their catalytic facets with real active sites are also identified by in situ synchrotron X-ray absorption spectroscopy and density-functional theory calculations. Our work enables facet engineering in the multi-elemental space and unveils the critical needs for their future development toward catalysis.
Ionic Transport Mechanism of All-Solid-State Lithium Batteries with Barium Titanate Nanofillers
Authors: Lai Chi-Yen , Huang Yu-Yao , Yeh Che-Ning
Published: December 2024

Liquid electrolytes are widely used in rechargeable batteries but face challenges such as flammability, leakage, and limited ability to suppress dendrite formation. In contrast, solid-state electrolytes offer higher safety and better dendrite suppression capability, mitigating risks associated with liquid electrolytes. The materials that are commonly used for solid-state electrolytes include ceramics and polymers. Although ceramic electrolytes exhibit higher ionic conductivity with excellent dendrite suppression ability, their interfacial contact with electrodes is poor. In contrast, polymer electrolytes exhibit excellent interfacial contact with electrodes but suffer from lower ionic conductivity. Therefore, combining polymers as the matrix and ceramics as the fillers to form composite polymer electrolytes (CPEs) shows promise in enhancing their electrochemical properties.

Ferroelectric materials, known for their ferroelectricity and high dielectric constant, have shown their potential as fillers to enhance ion transport and lithium salt dissolution in solid-state electrolytes. In this work, we choose BaTiO3 (BTO) as the filler due to its high dielectric constant and induced electric field under an applied electric field. The dielectric constant and ionic conductivity of CPEs is affected by the amount of added fillers, with an optimal content for conductivity and cycling performance. To date, few studies have explored the relationship and mechanism between the dielectric constant of ferroelectric material fillers and their electrochemical properties. We aim to investigate this relationship by adjusting grain size, morphology, and doping content of fillers to modify their dielectric constants, thereby deepening our understanding of this material system.
Pt Ternary Alloy with Rare Earth Metal - Pt5Ce-Co Intermetallic Nanoparticles as Highly Active Catalyst for Oxygen Reduction Reaction in PEMFCs
Authors: Zhang Hannah , Jeon Sungho , Vander Pas Brooke E. , Bai Jianming , Zhang Hong , Zhu Guangqi , Behzadnia Mohammad , Filippelli Gabriel M. , WANG Feng , Liu Ping , Stach Eric A. , Xie Jian
Published: December 2024

Platinum-based alloy catalysts have been extensively studied for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) because their superior enhancement in activity and durability. Alloying with rare earth (RE) elements is an important direction of exploring in Pt-based alloy design, due to its electronic configurations that can provide additional pathways for tailoring the electronic structures of active elements through alloying. Pt-RE alloys show more negative formation enthalpy than the widely applied late transition metal-based Pt alloys, which makes them thermodynamically and kinetically stable. The recently developed solid-phase synthesis strategy makes the nanoscale RE-based alloys more applicable. Here we reported a ternary intermetallic alloy of Pt5CeCo/C synthesized by two step-reduction method, annealing in diluted H2 under high temperature. Due to the unique 4f orbital of Lanthanoids Ce and the contraction effect, the electronic valence state of Pt alloys was modified, thus, optimizing the adsorption energy of the the reaction intermediates over the catalyst active sites, and effectively improving the electrocatalytic performance of the catalysts. It appears that the introduction of Ce greatly improves the ORR activity and fuel cell performance of Pt5CeCo/C, which achieved 2.8 A∙mgPt
-1 of mass activity and 78.1 m2∙gPt
-1 of ECSA using rotating disk electrode (RDE), while it is only 0.62 A∙mgPt
-1 and 75.2 m2∙gPt
-1 for Pt3Co/C, respectively. After 30k of accelerated stress test (AST) on RDE, Pt5CeCo/C can maintain 1.4 A∙mgPt
-1 of mass activity, far exceeding Pt3Co/C and commercial Pt/C. For membrane electrode assembly (MEA) test, Pt5CeCo/C shows an initial mass activity of 724 mA∙mgPt
-1, and a current density of 1876 mA∙cm-2 at 0.7 V under heavy-duty vehicle (HDV) testing conditions, while it still remains 1400 mA∙cm-2 at 0.7 V after 30k AST. This work provides an avenue to design advanced PGM ternary alloys by incorporating rare-earth metals to promote the catalyst performance.
Surface Engineering of Cobalt Nano Cube by Enhanced Nitrogen Content in Surface Carbon Shell for Efficient Hydrogen Evolution Reaction in Anion Exchange Membrane Water Electrolysis
Authors: Kang Byeong Guk , Lee Ru Li , Kim Tae Hong , Kang Bong Kyun
Published: December 2024

To address the pressing concerns of fossil fuel depletion and environmental degradation, extensive research is underway on hydrogen production via water electrolysis. The formidable energy barrier inherent in electrochemical water decomposition significantly impedes efficient hydrogen generation, thus necessitating the development of highly effective electrocatalysts.

Surface modifications of transition metals offer a promising avenue for reducing the energy barrier associated with the hydrogen evolution reaction (HER), as well as the hybrid structure with carbon materials can augment electrical conductivity and structural resilience. Furthermore, surface engineering through nitrogen doping on carbon shells can furnish electrochemically active catalytic sites.

In this study, we present the synthesis of Cobalt-Iron nano cubes encapsulated within a nitrogen-doped carbon shell. The N-doped carbon shell was obtained through the calcination of a polymer layer coated on a Co-Fe Prussian blue analogue precursor. Additionally, the nano cubes were further encapsulated in a melamine layer to enhance the nitrogen dopant content, thus optimizing the electrocatalytic performance.

The optimized CoFe@highly n-doped shell exhibits a low overpotential (98.2 mV) than CoFe@n-doped shell (133.2 mV) at 10 mA cm-2 on alkaline HER performance, and the exhibited performances were stable after 3,000 CV cycles. To commercialize electrocatalyst for hydrogen production, the CoFe@highly n-doped shell was applicated on anion exchange membrane (AEM) device. The CoFe@highly n-doped shell as cathode catalyst in AEM water electrolyzer shows low cell voltage of 1.808 V to achieve current density of 0.5 A cm-2.
Molecular Characterization of PFSA Ionomer Dispersions and Their Aggregated Structures
Authors: Shin Jaeman J
Published: December 2024

Perflurosulfonic acid (PFSA) ionomers are widely used in numerous polymer electrolyte-based electrochemical devices including fuel cells and water electrolyzers. The majority of the state-of-the-art PFSA ionomers consist of chemically robust hydrophobic perfluorocarbon backbone and vinyl ether side chains terminated with hydrophilic sulfonic acid groups, which are highly incompatible. Therefore, such architecture allows hydrophobic-hydrophilic microphase-separated morphologies in a membrane to induce fast proton conduction. However, dispersion-cast ionomers cannot necessarily offer good performance over long periods, and thus it is important to understand the ionomer dispersion in molecular scale as well as aggregated state to correlate the dispersion characteristic with the performance of final dispersion-cast membrane film. Here, we investigate the physical characteristics of PFSA ionomer dispersions, with a particular focus on the molecular weight of ionomers. A series of commercial ionomers with various compositions were obtained and characterized in terms of equivalent weight (EW) and melt flow index (MFI). Ionomer dispersion was produced by screening various aqueous/alcohol and polar solvents with varying concentrations dispersing temperature, to achieve nanodispersion with an aggregate diameter being smaller than 20 nm, as confirmed by the light scattering measurement. Furthermore, size-exclusion chromatography (SEC) of ionomers was performed to determine the molar mass distribution of ionomers, in addition to providing information on the aggregation number of ionomer chains in the dispersion state. Additional characterization of the ionomer dispersion with multiangle light scattering (MALS) provided an estimate of the absolute molar mass of the ionomers, which implements the possible inaccuracy of the molecular weight obtained from SEC arising from the ionomer-column interaction. Combining these results allows correlation between the hydrodynamic radius of ionomer dispersion as a function of molecular weight (or MFI) values. Moreover, ionomer nanodispersion was cast into membrane film for rheological and morphological characterization to further establish the correlate between the physical properties of ionomer dispersion and membrane.
Unraveling Chemical Degradation in PEM Water Electrolyzers: Factors, Stressors, and Membrane-Level Solutions for Enhanced System Lifespan
Authors: Chen Yingying , Setzler Erin , Barrett Brian , Agapov Alexander
Published: December 2024

Proton Exchange Membrane (PEM) water electrolyzers stand at the forefront of sustainable energy generation, offering a promising pathway toward carbon-neutral fuel production. Commercial systems require operation times > 50,000 hours. However, chemical degradation of PEMs remain a critical challenge affecting the longevity of the systems. One expected mode of degradation is that hydrogen peroxide is formed at the cathode in PEM water electrolyzers due to the low potentials and presence of platinum, hydrogen, and crossover oxygen. The hydrogen peroxide can participate in Fenton’s reactions to produce radicals that attack vulnerable sites of the ionomer. The radicals may be formed in the membrane or the electrodes and degrade the ionomer in both locations. Furthermore, the impact of degradation products, like short-chain ionomer fragments or hydrogen fluoride, on other system components is unknown. Overall, the underlying mechanisms and the key impact factors involved are not yet fully understood.

Moreover, new product development for PEMs face the challenge to deliver robust products within shorter development timelines than the actual system operation allows. Consequently, there’s a pressing need for accelerated stress testing (AST) to evaluate new materials and assess mitigation effectiveness against specific membrane failure modes. Understanding the factors that accelerate chemical degradation and deconvoluting sources of performance loss is necessary for developing AST protocols.

In this study, we intended to elucidate the intricate mechanisms underlying chemical degradation in PEM water electrolyzers. Chemical degradation is monitored through the loss of fluoride ions and post-mortem characterizations like SEM and FTIR. We explore the impact of various environment and operating parameters on degradation rate, such as water quality/contamination, water flow rate, operating temperature and pressure, and current density / voltage. These factors are explored in a flow-through system where concentration of water is needed for a detectable fluoride signal. Methods for concentrating water will be discussed.

By elucidating the factors impacting chemical degradation and identifying key stressors, insights from this study can be used to develop informative AST protocols, essential for accelerating the evaluation of materials with improved conductance-crossover-durability tradeoff, and therefore enabling more robust and efficient PEM water electrolyzer systems.
Overcoming Challenges in Ion-Pair Membrane Technology: Advancements in Fuel Cells and Electrochemical Hydrogen Pumps
Authors: Chhetri Manjeet , Kim Youngkwang , Maurya Sandip , Park Hyounmyung , De Castro Emory S. , Kim Yu Seung
Published: December 2024

The Membrane Electrode Assembly (MEA) stands as the pivotal element in electrochemical devices such as fuel cells and electrochemical hydrogen pumps (EHP). Notably, ion-pair High-Temperature Proton Exchange Membrane Fuel Cells (HT-PEMFCs) with reduced phosphoric acid concentrations within the MEA have been innovatively designed, allowing for the integration of diverse ion-conducting binders, known as ionomers, into both the cathode and anode electrodes [1]. This study delineates initial distinctions in MEA configurations among different device types (HT-Fuel cell and EHP, conducting a comprehensive analysis of performance disparities between traditional polybenzimidazole-based systems and various ion-pair proton exchange membranes [2].

Subsequently, a detailed exploration unfolds, focusing on the utilization of ion-pair membranes and different ionomer types for the three aforementioned devices. This comprehensive examination offers a unified comparative analysis encompassing ionomer type, membrane thickness, catalyst:ionomer ratio, and phosphoric acid doping levels, particularly in the context of performance at intermediate temperatures (160℃). Conclusions are drawn based on results derived from both half-cell and single-cell evaluations. Finally, overarching guidelines are presented to inform the formulation of high-performance MEA configurations tailored for ion-pair HT-PEMFCs and EHPs.

References:

[1] Lim, K. H.; Lee, A. S.; Atanasov, V.; Kerres, J.; Park, E. J.; Adhikari, S.; Maurya, S.; Manriquez, L. D.; Jung, J.; Fujimoto, C.; Matanovic, I.; Jankovic, J.; Hu, Z.; Jia, H.; Kim, Y. S. Protonated phosphonic acid electrodes for high power heavy-duty vehicle fuel cells, Nature Energy, 7, 248 (2022).

[2] Lim, K, H; Matanovic, I; Maurya, S; Kim Y; De Castro E. S; Jang, J-H; Park, H; Kim, Y.S. High Temperature Polymer Electrolyte Membrane Fuel Cells with High Phosphoric Acid Retention. ACS Energy Lett., 8, 1, 529–536 (2023).
High-Performance Bipolar Membranes for Direct Seawater Electrolysis
Authors: Song Hyeon-Bee , Kang Moon-Sung
Published: December 2024

Hydrogen (H2) is an important energy carrier for the development and maintenance of a low-carbon economy through sustainable energy generation. Direct seawater electrolysis (DSWE), which produces hydrogen using seawater, an infinite resource, as an electrolyte, is a very promising process. However, hydroxide ions generated from the hydrogen evolution reaction at the cathode cause precipitation of multi-valent cations contained in seawater, which blocks the active sites of the catalyst and induces high cell voltage. In this study, a high-performance bipolar membrane (BPM) was developed to effectively prevent the formation of inorganic deposits in the direct seawater electrolysis process. BPM has a structure in which a cation-exchange layer and an anion-exchange layer are superimposed and the characteristic of generating H+ and OH- ions by decomposing water molecules under reverse bias conditions. Therefore, the BPM has been actively used to produce acids and bases from salts, and its use has recently been expanding in energy conversion processes such as a fuel cell. In this study, a high-performance BPM was fabricated using woven fabric support and a specially designed transition metal-based catalyst that can significantly improve water decomposition performance. The prepared membrane had an efficient water-splitting catalyst and a 3D bipolar interface, showing excellent water-splitting capability and interfacial stability. In addition, it was confirmed that using the prepared BPM greatly contributes to stable hydrogen production when applied to the DSWE process. This work was supported in part by the NRF grants (NRF-2022M3H4A4097521) as well as by the framework of the research and development program of the KIER (No. C2-2473).
When Wetting Spills into Formation: Using Acoustics to Probe Electrolyte Dynamics in Lithium Ion Batteries
Authors: Thorsteinsson Gunnar , Steingart Daniel A.
Published: December 2024

Wetting is a critical step of lithium-ion battery manufacturing. Following electrolyte filling and sealing, the electrolyte percolates through the porous matrix of the electrodes to encapsulate and penetrate the active particles. This impregnation facilitates necessary ionic conductivity and passivation on formation, resulting in maximum capacity retention during cycling. Unfortunately, incumbent electrochemical techniques fail to fully elucidate this process, particularly in multilayered cells. In this work, we leverage acoustics to demonstrate that the wetting process is not simply a function of thermotemporal conditions but invariably continues into the formation cycles. In particular, transmitted acoustic signal energy is shown to be a function of wetting and a predictor for subsequent cycling performance. The spatial extent of wetting is probed using a purpose-built acoustic scanning apparatus, and a high-throughput fixed-location jig yields a statistical distribution for multiple cells under various wetting and formation conditions. These insights indicate that the two-step pre-cycling conditions should not be considered two separate processes but rather intimately entangled.
Is High Current Density Necessarily Unfavorable for the Cycling of Zn-Ion Batteries? An in Situ XRD Investigation
Authors: Ma Yifan , Pepas Jakub , Zhang Guangxing , Kang Minju , Carsley John , Chen Hailong
Published: December 2024

High rate (i.e., high current density) cycling has always been discouraged in the practice of Li-ion and Na-ion batteries because the charging/discharging high current can expedite the electromechanical degradation of the cathodes and result in dendrites formation on the anodes. But is this a universal rule of thumb for all rechargeable batteries? Our recent research on Zinc-ion batteries (ZIBs) shows that this might not be the case. ZIBs employing aqueous electrolytes show great promise for large-scale energy storage due to their affordability, environment-friendliness, and safety. ZIBs also suffer from the formation of harmful zinc dendrites. Conventionally, it was believed that high current density exacerbates dendrite growth, as seen in the electrodeposition of metals like Li. Yet, our recent research indicates that high-current deposition in metallic zinc anodes yields a dense, even layer with a specific (002) texture, thus enhancing cycling lifespan. Conversely, low-current deposition leads to porous, dendritic structures and reduced cycling longevity. Leveraging advanced synchrotron-based in situ X-ray diffraction, we have systematically investigated zinc deposition under varied conditions, unveiling a novel mechanism behind texture formation. These insights inform the development of new cycling protocols to extend the durability of ZIBs significantly.
Revealing Structure-Property Correlations in New Solid Electrolyte Materials for All-Solid-State-Batteries Using Synchrotron X-Ray Analysis
Authors: Han Da-Seul , Nam Kyung-Wan
Published: December 2024

There have been enormously increasing demands for developing next-generation Li-ion batteries with enhanced energy & power density and safety features compared with the current state-of-the-art LIB technology. Such advances necessitate the successful development and implementation of the new cathode, anode, and (solid)electrolyte materials. In this regard, understanding the structure-property correlation of advanced battery materials has now become a central aspect of battery research. Synchrotron-based x-ray techniques such as x-ray diffraction (XRD) and x-ray absorption spectroscopy (XAS) have been identified as ideal and powerful tools for in situ studies of lithium-ion battery materials. This presentation will discuss how such advanced characterization tools can be employed in the diagnostic study of battery materials to reveal the working and failure mechanism. I will present the application of various synchrotron x-ray tools, including pair distribution function (PDF) analysis and tender x-ray absorption spectroscopy, to investigate sulfide and halide-based solid-electrolyte materials. The correlation between local atomic structure changes and ionic conductivity will be discussed.
Surface Wetting Properties of Lithium Anode Characterized Using Laser Scanning Confocal Microscopy
Authors: Yakovleva Marina , Xia Jian , Fitch Brian
Published: December 2024

Surface wettability between the lithium metal anode and liquid electrolyte is a critical performance characteristic. Poor wettability can result in nonuniform stripping and deposition of lithium metal, nonuniform SEI formation, formation of dead lithium and; thus, shorter cycle life. Imaging techniques such as laser-induced fluorescence imaging using laser scanning confocal microscopy (LSCM), have become a valuable tool for investigating the surface properties of lithium metal anodes.1 Laser scanning confocal microscopy is an advanced microscopy technique that allows improved depth resolution relative to traditional optical microscopy.

Arcadium Lithium Corporation has developed LIOVIX®printable lithium technology, a formulation that can be printed, at industrial speed, on most common substrates, such as Cu foil to produce thin lithium metal foil with thickness in the range of 5 µm to 50 µm with no limitation in width.2 LIOVIX®-based lithium film has a different microstructure when compared to a commercial foil (Figures 1a and 1b). LIOVIX-based thin foil retains rheology modifiers used in the formulation that serve as a 3D skeleton. This unique structure can change lithium metal surface plating behavior. Therefore, the 3D structure might mitigate the growth of dendritic lithium, reduce mechanical degradation, and improve safety and cycle life of the battery.

LSCM was used for in-situ, in operando observations of the difference in surface properties and wettability properties of commercial lithium foil and LIOVIX-based lithium foil (Figures 1c and 1d). Lithium metal surface is dynamic and prone to forming various structures and compounds, depending on the conditions it is exposed to. The results showed that LIOVIX-based foil lithium activity is more homogenous and had a shallower interaction when compared to the commercial lithium foil. This potentially signifies more uniformity to the lithium activity in LIOVIX-based foil vs. commercial lithium foil; thus, more uniform surface activity within a battery system.

Reference

Nishikawa et al., 2010 J. Electrochem. Soc. 157 A1212

Yakovleva et al., Battery utilizing printable lithium, U.S. Patent 11, 824, 182, B2, Nov. 21, 2023

Figure 1. Microscope image of A) LIOVIX® -based lithium foil (20um), B) commercial lithium foil (20um); and 3D Confocal microscope images of C) LIOVIX®-based lithium foil (20um) and D) commercial lithium foil (20um).

Figure 1
Development of in Operando Technique for Modification TiO2 Based Li-Ion Anode Materials Application
Authors: Shen Yu-Min , Ho Cheng-Hsun , Chong Zhen , Yang Chih-Lung , Chang Chia-Chin , Huang Jow-Lay
Published: December 2024

TiO2 has emerged as a focus in the research of new anode electrode materials for lithium-ion batteries due to its exceptional stability, cycling performance, and environmental friendliness. However, the fatal issue of TiO2 series anode electrode materials is their relatively low specific capacity (335 mAh/g). In response to this challenge, our research team has proposed surface modification methods to enhance their capacity, such as SnO2@TiO2 and MoOx@TiO2. This study found that the initial delithiation capacity of TiO2 modified with Tin Dioxide and MoOx at rate of 0.1C reached 440 and1273 mAh/g, respectively, with lithiation capacity of 706 and 780 mAh/g, respectively. The capacity retention can remain at 80% after 100 cycles for both of the samples. While successful surface modification of TiO2 negative electrode materials has been achieved in this study, mechanisms of sustaining high capacity and enhancing initial Coulombic efficiency remain crucial topics for discussion. We will employ in-situ analysis techniques to investigate the phase changes of lithium ions during charge and discharge processes and identify key factors for improving initial Coulombic efficiency.

In evaluating the influence of lithium-ion insertion/extraction, our team utilized in-situ XRD analysis as the field technique. The XRD results revealed that besides the irreversible formation of Li0.55TiO2 during charge and discharge processes leading to reduced discharge capacity, SnO2 exhibited reversible behavior during lithium-ion insertion/extraction, while in the MoOx series, overall phase transitions occurred as MoO2 and MoO3. Subsequently, our research team will conduct further computational analysis on the lithiation amount of SnO2 and MoOx. Addressing the issue of initial Coulombic efficiency, our team initially employed in-situ thermal analysis techniques to understand the heat absorption/release phenomena in the plateau region of surface-modified TiO2 and applied pre-lithiation techniques at different potentials. Through this approach, it was observed that pre-lithiation of surface-modified SnO2 at specific potential improved the initial Coulombic efficiency from 60% to 90%; while the pre-lithiated MoOx remained the initial Coulombic efficiency at 70%

By in-situ techniques, our research team aims not only to effectively enhance various properties of surface-modified TiO2 materials but also to establish their commercial viability in the future.

Keyword: modification TiO2 anode, in situ XRD, in situ thermal analysis, pre-lithiation
Observing the Nanoaggregates in the Electrolytes by Small-Angle X-Ray Scattering
Authors: Li Tao
Published: December 2024

The solution solvation structure of the liquid electrolyte directly affects transport properties, which ultimately determines the performance of batteries. It has been predicted that the nanoscale units such as clusters and aggregates in the liquid electrolytes, especially as the salt concentrations increase. However, more is needed to know about these structures due to the limitations of the traditional methods. Currently, there are no direct methods that can be used to investigate the cluster or nanoaggregates in the electrolytes. Herein, we demonstrate that small-angle X-ray scattering-wide angle X-ray scattering (SAXS-WAXS), and even ultra-small-angle X-ray scattering (USAXS) could be applied to capture these larger aggregates in the electrolytes, including conventional organic electrolytes, high concentration electrolytes, water-in-slat electrolytes, and redox-active electrolytes. Raman, neutron scattering, IR, and molecular dynamics (MD) simulations further support the proposed structures. This work highlights the fundamental structure analysis in the nanoscale, which will prompt better electrolytes in the future.
Computational Discovery of Optimal Dopants for Electrode to Enhance Sea Water Splitting
Authors: Jung Hyeonjung , Song Jihyeon , Lee Yechan , Jung Han Sol , Park Sung Il , Kim Minseong , Park Sangmin , Han Jeong Woo
Published: December 2024

A strategic approach has been proposed for designing robust, high-performing oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) catalysts tailored for saline/sea water splitting. By employing a density functional theory (DFT)-based computational screening process, a set of promising dopants were identified from a range of twenty-six 3d to 5d transition metals, with the aim of enhancing the activity and saline water resilience of the catalysts. The screening methodology was threefold, encompassing evaluations of OER / HER energetics, chlorine evolution reaction (ClER) energetics, and chloride-corrosion energetics. The screening led to the promising dopants, which substantially elevated the performance of each of the host catalysts. This study contributes to the understanding of alkaline ClER and chloride-corrosion mechanisms, providing insights into catalyst behavior in saline/sea conditions.
Computational Fluid Dynamics Analysis of Gas Crossover in an Alkaline Electrolyzer Using a Multifluid Model
Authors: Martinho Diogo Loureiro , Abdollahzadehsangroudi Mohammadmahdi , Berning Torsten
Published: December 2024

Green hydrogen has emerged as a key solution for high-intensity energy storage, with various technologies introduced to facilitate its production, including alkaline electrolyzers (AWE), proton exchange membrane electrolyzers, and solid oxide electrolyzers. While each of these technologies presents unique strengths and weaknesses, alkaline electrolyzers are particularly noted for their cost-effectiveness and robust structure in hydrogen production. However, a comprehensive understanding of the internal dynamics of the electrolyzer during operation requires detailed modeling.

This study aims to delve into the dynamics of AWE, optimizing operational parameters and cell design to enable higher current operation without increasing voltage losses, thereby enhancing overall efficiency. Computational fluid dynamic modeling is employed to achieve this goal, focusing on gas bubble behavior within the electrolyzer, their impact on cell performance, and the dynamics of mass transfer between different phases.

One drawback of alkaline electrolyzers is the crossover of hydrogen and oxygen through the membrane, resulting in reduced hydrogen purity and increased hydrogen loss. The preset study investigates the effect of electrolyte saturation levels on crossover, highlighting its significance. Additionally, a parametric study is conducted, varying bubble diameter across simulations to further understand its implications.

Figure 1
Proton Incorporation and Electrical Leakage in BaZrO3 and BaCeO3
Authors: Varley Joel , Ogitsu Tadashi , Li Meng , Rowberg Andrew
Published: December 2024

Molecular hydrogen (H2) is a vital next-generation energy carrier, due to its high energy density, universal abundance, and ability to produce electricity in a fuel cell without greenhouse gas emissions. Critical to the adoption of hydrogen energy is the ability to produce H2 cleanly via the electrolysis of water. Solid oxide electrolyzer cells (SOECs) are attractive technologies to achieve this goal, as they can use excess thermal energy or other renewable energy sources to convert water into H2. However, the fundamental physics that determines the performance of SOECs—including sources of performance loss and degradation—is relatively poorly understood.

Here, we describe first-principles calculations based on hybrid density functional theory (DFT) aimed at studying efficiency loss in proton-conducting SOECs based on the oxide electrolytes BaZrO3 (BZO) and BaCeO3 (BCO). These materials are acceptor-doped with a trivalent element such as yttrium to introduce protons; however, such doping can also increase electrical leakage in devices, which limits their Faradaic efficiency. Our calculations describe the properties of localized polarons in BZO and BCO: hole polarons form favorably in both materials, while electron polarons are only stabile in BCO and in Ce-containing alloys. Under typical operating conditions, large concentrations of hole polarons may be present; therefore, to limit the risk of p-type electrical leakage, it is advantageous to avoid extreme oxygen-rich conditions and high dopant concentrations [1].

High ionic conductivity also requires large proton concentrations. We examine avenues to achieve this requirement by calculating the formation energy of protons and their concentrations under various conditions. Proton concentrations will be highest under wet conditions, with oxygen vacancies becoming more dominant under drier conditions. Encouragingly, higher protonation levels correlate with lower concentrations of hole polarons, implying lower electrical leakage with higher hydration levels. In addition to traditional protonation pathways, we also explore a novel hydrogenation mechanism via hydroxyl incorporation, which does not require acceptor doping. However, this process is unfavorable except under extremely wet conditions [2].

These results provide crucial insights for understanding the complex behavior of these materials in situ. Determining how to promote ionic conductivity at the expense of electrical leakage is critical to optimizing their performance in SOECs and related devices.

This work was performed under the auspices of the U.S. DOE by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

[1] A. J. E. Rowberg, M. Li, T. Ogitsu, J. B. Varley, Phys. Rev. Mater. 7, 015402 (2023).

[2] A. J. E. Rowberg, M. Li, T. Ogitsu, J. B. Varley, Mater. Adv. 4, 6233-6243 (2023).
Influence of Morphology and Surface Chemistry on Ni-Exsolved Perovskite Oxides for Direct Ammonia Solid Oxide Fuel Cells
Authors: Kim Keejung , Joh Dong Woo , Kim Hye-Sung , Lee Seung-Bok , Lim Tak-Hyoung , Park Seok-Joo , Song Rak-Hyun , Hong Jong-Eun
Published: December 2024

Ni-YSZ as an anode material for solid oxide fuel cells (SOFCs) has shown excellent catalytic, electrical, and thermal properties. However, when applied to direct ammonia (DA) fed SOFCs, Ni coarsening and microstructural degradation caused by Ni nitrification resulted in a decrease in the electrode reactivity and an increase in contact resistance, thereby reducing the performance of DA-SOFCs. Nano-size metal exsolved perovskite oxides have been intensively investigated as an alternative anode due to superior catalytic activity and anti-coarsening under various fuel conditions. In this study, Ni exsolution behavior, ammonia decomposition, and surface chemistry on Ni substituted (La,Sr)0.8TiO3-
δ oxides were analyzed. Then it was applied to the anode of DA-SOFCs to evaluate cell performance and durability. Ni exsoluted oxides were efficient to decompose ammonia at reduced temperatures due to enlarged catalytic sites and electronic donation. The cell using Ni exsoluted perovskite anode indicated a significant improvement of durability for excellent catalyst stability while the cell performance was comparable with that of Ni-YSZ based DA-SOFC.
Fluoride Ion Conductivity and Crystal Structure Analysis of Ba4Bi3F17 with Fluorite-Type Units
Authors: Hirakawa Saya , Shimoda Keiji , Kawaguchi Shogo , Orikasa Yuki , Zhong Chengchao
Published: December 2024

All-solid-state fluoride ion batteries are attracting attention as an innovative next-generation battery that can replace lithium-ion batteries due to their high energy density. For fluoride ion conductor, three main types of crystal structures have been reported: fluorite-type, tysonite-type, and perovskite-type. Among these, fluoride ionic conductors with fluorite-type structure show the best conductivity. In fluorite-type BaF2, 4-coordinated fluoride ions are difficult to move within the crystal structure, and it has been reported that the addition of La3+ with different valence improves conductivity by inserting fluoride ions into interstitial sites within certain solid solution regions.[1] The addition of Bi3+ results in the formation of a cation-ordered structure Ba4Bi3F17 in certain solid solution regions, which has fluorite-type structural units derived from BaF2 in the structure. Reports on Ba4Bi3F17 are limited to its crystal structure[2] and there are no studies on it as an ionic conductor. In this study, the fluoride ion conductivity and fluoride ion conduction pathway of Ba4Bi3F17 was evaluated and compared with those of BaF2 with fluorite-type structure.

To synthesise Ba4Bi3F17, BaF2 and BiF3 were weighed in an Ar atmosphere, mixed for 10 min. After pressing into a φ10 pellet, it was wrapped in a Ta container and sealed in a quartz tube, following by calcining at 773 K for 24 hours. Samples were identified by powder X-ray diffraction and AC impedance measurements were performed to assess their conductivity.

Powder X-ray diffraction results showed that Ba4Bi3F17 was successfully synthesized and exhibited Fluoride ion conductor of 1.63 × 10−6 S cm−1 at 473 K. Further analysis of the fluoride ion conductor pathways showed that fluoride ions in Ba4Bi3F17 conduct in a four-coordinate to four-coordinate conduction pathway, which is different from the conventional four-coordinate to six-coordinate conduction pathway in BaF2 with fluorite-type structure. These results indicate that even the same structural unit can change fluoride ion conductor pathways depending on the surrounding environment.

[1] Kazuhiro Mori et. al., ACS Appl. Energy Mater., 2020, 3, 2873-2880

[2] E.N. Dommbrovski et. al., Solid State Chemistry, 2004, 177, 312-318
Sustainable Desalination Waste Brine Management through Electrochemically Supported CO2 mineralization and Multiple Product Recovery
Authors: Tu Weihan , Zhao Ya , Chan Wei Ping , Lisak Grzegorz
Published: December 2024

Seawater reverse osmosis desalination (SWRO) is a vital technology for low cost and energy requirement water production to ensure regional water security and continued economic development. However, the state-of-the-art technology typically exhibits a recovery rate of around 42% converting in 58% of the seawater input into desalination waste brine which are largely discharged into the sea1. Significant works on brine utilization have shown that SWRO desalination brine can be converted into usable feed for chlor-alkali process with simultaneous carbon capture capabilities2,3,4. In this work, the desalination effect of electrochemistry for simultaneous utilization and treatment of desalination brine (56.0 ± 2.1 g/L) into seawater level (32.0 ± 1.4 g/L) was explored. The results demonstrate chemical self-sufficiency for desalination brine treatment (removing Mg2+ and Ca2+ to below ppm level), electrochemically recovering chlorine (95% – 99% selectivity, and hydrogen gas (92% – 97% selectivity), and conversion of desalination brine into reclaimed seawater discharge (RSD). The RSD is further chemically dechlorinated and neutralised to pH 7.3 to be safe to discharge into the sea. The excess alkali brine is used to capture additional CO2 in the form of bicarbonates achieving net abatement in climate change impact (9.90 CO2 e/m3) after product carbon abatements are accounted.

1 Jones, E.; Qadir, M.; van Vliet, M. T. H.; Smakhtin, V.; Kang, S. The State of Desalination and Brine Production: A Global Outlook. Science of The Total Environment
2019, 657, 1343–1356.

2 Melián-Martel, N.; Sadhwani, J. J.; Ovidio Pérez Báez, S. Saline Waste Disposal Reuse for Desalination Plants for the Chlor-Alkali Industry: The Particular Case of Pozo Izquierdo SWRO Desalination Plant. Desalination
2011, 281, 35–41.

3 Du, F.; Warsinger, D. M.; Urmi, T. I.; Thiel, G. P.; Kumar, A.; Lienhard V, J. H. Sodium Hydroxide Production from Seawater Desalination Brine: Process Design and Energy Efficiency. Sci. Technol.
2018, 52 (10), 5949–5958.

4 Choi, W. Y.; Aravena, C.; Park, J.; Kang, D.; Yoo, Y. Performance Prediction and Evaluation of CO2 Utilization with Conjoined Electrolysis and Carbonation Using Desalinated Rejected Seawater Brine. Desalination
2021, 509, 115068.

Figure 1
Desalination-Coupled (photo)Electrocatalysis for Production of Value-Added Chemicals
Authors: Park Hyunwoong
Published: December 2024

Water and energy are the most essential elements for a sustainable human society. They are strongly interdependent because energy production requires a significant amount of water, while the production, processing, distribution, and end-use of water requires large energy inputs. Several water-energy nexus technologies have emerged, including PV-electrolysis and microbial desalination. Herein, we propose a hybrid process that is driven by sunlight and boosted by electrodialysis. A sunlit inorganic photoanode initiates the desalination of saline water in the middle cell. As the chloride in the middle cell moves to the anode cell, the wastewater (WW) treatment is boosted by reactive chlorine species (RCS) generated via the reaction with photogenerated holes. An increase in the electrical conductivity in the anode cell further enhances the photoelectrocatalytic (PEC) WW treatment. Upon a potential bias, various value-added chemicals (H2 via water reduction, H2O2 via O2 reduction, and HCOOH via CO2 reduction) are produced in the cathode cell, and the production of the chemical is enhanced as the desalination proceeds because of sodium enrichment (i.e., conductivity increase). The uniqueness and advantages of this hybrid process include its broad range of operating conditions (virtually the entire pH range) and the wide variety of inorganic and organic substrates that can be treated (i.e., aquatic pollutants), while desalination boosts the overall operation and chloride catalyzes the anodic reaction, which in turn facilitates the desalination. Although tested as a proof-of-concept, the present technology opens up a novel field involving a sunlight-water-energy nexus, promising high efficiency desalination and the desalination-boosted remediation of water with simultaneous production of value-added chemicals.