bluuebunny/crossref_metadata_2025 huggingface dataset:
In-Operand Analysis of the Oxidative Stress of E. coli in Contact ZIF-67 by Electrochemical Detection of Hydrogen Peroxide
Authors: Martin Martinez Maria , Alvarez-Contreras Lorena , España Sanchez Beatriz Liliana , Arjona Walter Noe Velazquez
Published: December 2024

Detection of oxidative stress plays a crucial role in understanding bacterial damage, with the aim of developing effective antimicrobial strategies. Oxidative stress is a common consequence of various stressors, including antibiotic exposure, environmental toxins, and host immune responses. By detecting oxidative stress, researchers can gain insights which how bacteria respond to and resist these stressors, leading to a better understanding of the early stage of bacterial damage. Among these, Zeolitic Imidazolate Frameworks (ZIFs) emerge as promising antimicrobials characterized by their high surface area-to-volume ratios, rendering them well-suited for detecting bacterial damage and reactive oxygen species. In particular, ZIF-67 distinguished by its structure containing a cobalt ion and an organic ligand, exhibits unique properties, including antibacterial activity, and electrochemical sensing ability for detecting hydrogen peroxide. These attributes position it as an excellent candidate for bacterial inhibition and eradication. This study focuses on electrochemical detection of oxidative stress in E. coli bacteria triggered by hydrogen peroxide overproduction upon contact with Zeolitic Imidazolate Frameworks (ZIFs). For this purpose, ZIF-67 was synthesized via the solvothermal method as an antibacterial agent, while for detection purposes, the material was supported on carbon nanotubes (N-CNTs). Antibacterial activity assessments revealed an efficiency of 99.9% at concentrations ranging from 0.5 mg/ml after 3 and 24 hours, with lower concentrations exhibiting 72% efficiency, indicating promising suitability for antibacterial applications. Furthermore, ZIF-67/N-CNTs demonstrated notable sensitivity within the range of 20 - 100 ppm range, suggesting significant potential for electrochemical detection of hydrogen peroxide. Voltammetry cyclic and LSV were employed to evaluate the generation of peroxide due to oxidative stress induced upon contact between ZIF-67 and E. coli. The inclusion of these materials highlights the potential capacity to assess induced oxidative stress using electrochemical techniques for hydrogen peroxide detection.
(Invited) Improving Low-Temperature Lithium-Ion Battery Performance through 3D Structure-Controlled Anodes with Optimized Charge Storage Mechanisms
Authors: Lee Michael J , Lee Kyungbin , Ryu Kun , Lee Seung Woo
Published: December 2024

The performance of lithium (Li)-ion batteries (LIBs) significantly decreases at low temperatures, primarily due to the slow diffusion of Li ions within the graphite anode. This issue often necessitates the use of complex thermal control systems to safeguard the batteries, enhancing their cost, mass, and volume, especially under extreme conditions. Here, we introduce both structure-controlled graphene and graphite composite anodes, which employ controlled charge storage mechanisms to accelerate Li-ion charge storage kinetics and maintain structural stability under low-temperature conditions. [1-3] By transitioning from layered graphite to crumpled graphene or expanded graphite (composite), we effectively utilize diffusion- and surface-controlled charge storage mechanisms. These structure-controlled anodes exhibit superior rate capability and exceptional performance at temperatures as low as -50 °C. Through comprehensive low-temperature analyses, this research provides a detailed understanding of the relationships between anode structure, charge storage mechanisms, and performance under low-temperature conditions. Our findings offer valuable insights for the development of advanced energy storage devices optimized for low-temperature operation.

References

[1] K. Lee†, M. J. Lee†, J. Lim, K. Ryu, M. Li, S. Noda, S. J. Kwon*, S. W. Lee*, Controlled Nitrogen Doping in Crumpled Graphene for Improved Alkali Metal-Ion Storage under Low-Temperature Conditions. Advanced Functional Materials, 33, 2209775, 2023.

[2] K. Ryu†, M. J. Lee†, K. Lee, S. W. Lee*, ZnO-Embedded Expanded Graphite Composite Anodes with Controlled Charge Storage Mechanism Enabling Operation of Lithium-Ion Batteries at Ultra-Low Temperatures. Energy & Environmental Materials, 0, e12662, 2023.

[3] M. J. Lee, K. Lee, J. Lim, M. Li, S. Noda, S. J. Kwon, B. DeMattia, B. Lee*, S. W. Lee*, Outstanding Low-Temperature Performance of Structure-Controlled Graphene Anode Based on Surface-Controlled Charge Storage Mechanism. Advanced Functional Materials, 31, 2009397, 2021.
Experimental Extraction of Carbon-Binder-Domain Characteristic for Simulation Purposes
Authors: Pinilla Sergio , Zanotto Franco , Dominguez Diana Zapata , Rodríguez Tomás , A. Franco Alejandro
Published: December 2024

In the last years, there has been a substantial push in the lithium ion battery field to develop accurate electrochemical models that are capable of reproducing the response of experimental electrodes. There are myriad applications and uses of these models that range from material design to cell integration, providing means for a rational design of electrodes and cells, as well as diagnosis and prognosis tools during its life.1

Among all the models, electrode scale 3D mesoscopic electrochemical modeling approaches have gained substantial relevance due to the possibility of linking the electrochemical model with manufacturing models, creating a unique simulation pipeline that gathers all information from slurry to cell. 2

These 3D mesoscopic models count with an additional advantage compared to simpler models such as the p2D approaches, and it is the fact they account better for the microstructure, which is known to be very determinant in the electrode performance.3 These models usually consider three main domains inside the electrode, the active material, the carbon-binder domain and the pores. While the active material and its pore network have been better studied and can be more easily obtained by tomography, the carbon-binder domain and its distribution in the microstructure is harder to study 4 but extremely determinant in the properties of the electrodes.5 The carbon binder domain properties, such as its conductivity, porosity and tortuosity factor will determine the heterogeneity of the reactions happening in the electrodes. 5 However, until now, there is a lack of experimental approaches able to characterize the porosity and tortuosity factor of the carbon binder domain, and this is precisely the topic of this work. We propose a methodology to extract the characteristics of the carbon binder domain, namely its porosity and tortuosity factor, by combining electrode manufacturing, characterization and computational simulations.

Our methodology is based on the study of electrochemical impedance data over a wide matrix of cases in a systematic way using, as a proof of concept, well-characterized NMC electrodes and relating it with electrode-level simulation results.

The proposed methodology is completely general and independent of the cell chemistry, and not only provides a tool to better understand and simulate the behaviour of the carbon binder domain, but it is also demonstrated how it can be used to obtain experimental data that was not easily available before.

A. A. Franco et al., Chem.
Rev., 119, 4569–4627 (2019).

C. Liu, T. Lombardo, J. Xu, A. C. Ngandjong, and A. A. Franco, Energy Storage Materials, 54, 156–163 (2023).

T.-T. Nguyen et al., npj Comput Mater, 6, 123 (2020).

J. Landesfeind, M. Ebner, A. Eldiven, V. Wood, and H. A. Gasteiger, J. Electrochem. Soc., 165, A469–A476 (2018).

M. Chouchane and A. A. Franco, Energy Storage Materials, 47, 649–655 (2022).
Structural Evolution of Mn-Based Disordered Rock Salt Cathodes
Authors: Li Tianyu , Geraci Tullio Salvatore , Koirala Krishna Prasad , Wang Chongmin , Navrotsky Alexandra , Clement Raphaele J
Published: December 2024

Manganese-based disordered rock salt (DRX) oxides are promising new generation lithium-ion cathode materials due to the low costs and the high theoretical capacities. Recent research has revealed that DRX compounds with high manganese content, denoted as Li1+xMnyM1-x-yO2 (where y>0.5 and M represents hypervalent d0 ions such as Ti4+ and Nb5+), undergo a gradual capacity increase over initial charge-discharge cycles. This phenomenon coincides with the development of localized domains exhibiting a spinel-like cation arrangement within the overall disordered structure, termed the "δ phase."

In my presentation, I will detail our effort on systematically investigating the structural changes occurring in manganese-based DRX compounds at various levels of lithium removal through heating. Analysis using synchrotron X-ray, neutron diffraction and 7Li solid state NMR reveals that , during the structural relaxation of delithiated DRX, lithium and manganese/titanium cations selectively migrate to different crystallographic sites within the rock salt structure, driving the observed structural rearrangements. We confirm that the structural evolution is the major factor contributing to the capacity enhancement. Furthermore, our research shows that both manganese-rich and manganese-poor DRX oxides can undergo thermal relaxation into the δ phase at delithiated states. However, the relaxation processes in DRX with different Mn content result in distinct domain structures. Calorimetry measurements and in-situ heating XRD experiments suggest that the structural relaxation exhibits a stronger thermodynamic driving force and lower activation energy for manganese-rich DRX compounds compared to manganese-poor systems. This difference explains why the observed structural evolution occurs predominantly in the former category during battery cycling.

Figure 1
(Invited) Nanostructured Positive Electrode Materials for Li-Ion Battery Applications
Authors: Yabuuchi Naoaki
Published: December 2024

Ni-enriched layered materials are used as electrode materials of Li-ion batteries for electric vehicle applications. Stoichiometric LiNiO2 with cationic Ni3+/Ni4+ redox is the ideal electrode material, but the gradual loss of capacity at the high voltage region, associated with Ni ion migration, hinders its use for practical applications.1 Recently, the importance of non-stoichiometry and anti-site defects is discussed for LiNiO2, and highly reversible pure Ni-based layered materials without metal substitution is successfully developed through defects engineering.1

Another important target is the development of a practical and high-energy Co-/Ni-free Mn-based positive electrode material, which is necessary for the economical electric vehicles. Nanostructured Mn-based electrode materials are proposed as emerging materials for this purpose.2 However, these materials are generally synthesized by high-energy milling, which cannot be adopted for mass production. Recently, nanostructured LiMnO2 with high-energy density (~800 Wh kg–1) is successfully synthesized by using a conventional calcination reaction, which is potentially used for economical electric vehicle applications.3

To develop safe and high-energy Li-ion batteries, the use of solid electrolyte is an important strategy. Nevertheless, inevitable volume changes of electrode materials on cycling lead to the difficulty to maintain the stable interface between electrode materials and electrolyte. Recently, a nanostructured cation-disordered rocksalt oxide with a dimensionally invariable character is developed. Indeed, the excellent reversibility with solid electrolyte is achieved.5

From these results, the importance of nano-structured lithium insertion materials for practical Li-ion battery applications is discussed.

References

1) Konuma et al., and N. Yabuuchi, Energy Storage Materials, 66, 103200 (2024).

2) Kanno et al., and N. Yabuuchi, ACS Energy Letters, 8, 2753 (2023).

3) Miyaoka et al., and N. Yabuuchi, submitted

4) R. Fukuma et al., and N. Yabuuchi, ACS Central Science, 8, 775 (2022).

5) I. Konuma et al., and N. Yabuuchi, Nature Materials, 22, 225 (2023).
Novel Flame-Retarding Electrolyte for High-Energy and Safe Lithium Metal Battery
Authors: Vu Dung Tien Tuan , Lee Jiin , Kwak Sehyun , Tran Yen Hai Thi , An Kihun , Song Seung-Wan
Published: December 2024

Lithium metal battery (LMB) is a potential next-generation battery for higher energy storage device than state-of-the-art lithium-ion batteries. To obtain a high energy density of LMB, high mass loading of high-capacity cathode such as high-nickel LiNixCoyMnzO2 (NCM, x ≥ 0.8) and/or high-voltage operation (> 4.2 V) are needed. The inherent issues of LMBs at high-voltage are interface and thermal instability and structural degradation of NCM cathode. Moreover, the uncontrollable growth of lithium (Li) dendrites at Li anode often occur when using traditional carbonate-based flammable liquid electrolyte, resulting in the risk of battery safety. A suggested solution to mitigate those issues is the development of a less flammable liquid electrolyte that also forms stable solid electrolyte interphase (SEI) at the surface of cathode and anode. Herein, we report a flame-retarding electrolyte approach that enables the stable operation of a high-nickel NCM-based LMB under high voltage and high temperature.
Phase-Regulatable Ru-Based Nanocages with Near-Zero Overpotentials Toward Alkaline Hydrogen Evolution
Authors: Zhao Ming , Jiang Wenbin
Published: December 2024

Regulating the crystal phase of metal nanomaterials is crucial for heterogeneous catalysis, which, however, remains a grand challenge owing to the thermodynamic instability of unconventional crystal phases. Here, we report an one-pot synthesis of CuPd@Ru core-shell nanostructures with regulatable Ru phases from conventional hexagonal closed-packed (hcp) to unconventional face-centered cubic (fcc). By selectively removing the core via chemical etching, Ru nanocages with ultrathin walls were produced, with their crystal phases being well-preserved. Moreover, this method is robust for additional doping of metal atoms into Ru nanocages, offering further optimization of the catalytic properties of Ru nanocages. Advanced structure characterization and theoretical simulation show Pt is dispersed in the form of single atoms in Ru nanocages, which effectively tunes the electronic structure of Ru. When used as catalysts for alkaline hydrogen evolution reaction (HER), Pt-doped fcc Ru nanocages (Pt-Rufcc) exhibit excellent alkaline HER performance, with a near-zero overpotential at current density of 10 mA cm−2 and a low Tafel slope, outperforming most of the reported nanocatalysts. Further tests in the anion exchange membrane water electrolyzer confirm the superior performance of Pt-Rufcc to the commercial Pt/C. This work offers a versatile strategy to produce phase-regulatable nanocages toward green H2 production.
Unraveling the Role of Cu+3 in Oxygen Evolution Activity of Copper-Oxides
Authors: Basera Pooja , Bajdich Michal
Published: December 2024

Significant progress is currently being made in understanding the behavior of copper oxide (CuO) at positive potentials, approximately 1.7 V, under electrochemical conditions. While it is assumed to be hydrated Cu2O3 at this potential with ∆G = 208.5 kJ/mol, this hypothesis awaits validation. However, our calculations show that bulk CuOOH has ∆G ~209.5 kJ/mol, indicating Cu+3 possibly in the form of bulk CuOOH. To verify this, we employ a combination of density functional theory (DFT) electronic structure calculations and simulated Raman spectra. This approach allows us to examine the electrocatalytic activity of CuOOH polymorphs, including Cmc21 (β-CuOOH), Pmn21 (γ-CuOOH), and C2/m (δ-CuOOH), for the OER at this potential. Our calculations indicate a presence of stable square planar, non-magnetic γ/δ-CuOOH phase, and the calculated volume Pourbaix diagram highlights γ/δ-CuOOH as the newly discovered active phase governing the OER in alkaline media. This finding is further supported by simulated Raman spectroscopy, revealing distinct features corresponding to Cu3+ species at 552 and 573 cm-1, closely matching experimental data peak at 587 cm-1 only present under highly oxidizing conditions. Next, we compare the theoretical overpotentials of all CuOOH surfaces with O and OH-vacancy at the bridge site as the active site, and the surface-adsorbed OH* on a CuO surface. We find that the (021) surface of CuOOH and the (002) surface of CuOOH are the most active, characterized by an overpotential ranging from 0.36V to 0.50 V. Lastly, we demonstrate that the overpotential of the CuOOH (021) surface can be improved further by surface substitution of Cu by Fe. This finding could explain the experimentally observed enhancement in the OER activity of FeyCu1−yOOH thin films with increasing Fe content. This work expands our knowledge in understanding the active phases governing OER in alkaline media but also paves the way for the development of more efficient electrocatalysts for renewable energy applications.

Figure 1
Electrochemical Investigations of Chlorpyrifos-Induced Toxicity Effects in Astrocytic Glutamate Regulation
Authors: Xu Kaixuan , Neely M. Diana , Guel Camilla , Cliffel David E.
Published: December 2024

Glutamate is a major excitatory neurotransmitter in the central nervous system, and its homeostasis is critically regulated by astrocytic glutamate transporters. Dysregulation of astrocyte function has been implicated in the pathogenesis of various neurodegenerative diseases. The organophosphate pesticide chlorpyrifos (CPF) has raised significant public health concerns due to its documented neurotoxic effects, but the specific impacts of CPF on glutamate neurotransmission and metabolism within astrocytes remain poorly understood.

Here we designed and modified an electrochemical sensor to detect changes in glutamate levels following acute CPF exposure in astrocyte cultures. Our microclinical analyzer (µCA) paired with screen-printed electrodes (SPE) offers an automated sensing system that enables high-resolution monitoring of extracellular glutamate dynamics, providing insights into the effects of CPF on astrocytic glutamate regulation. Immobilized glutamate oxidase on electrode surfaces provided selective and sensitive glutamate detection. The temperature modification of electrodes through incubation (37°C) led to a nearly four-fold improvement in sensitivity (0.84±0.04 nA/µM), with low limits of detection (2.8±0.1 µM), and quantitation (9.3±0.5 µM). Our SPE detected glutamate from 1 to 600 µM which comprehends the physiological range in the brain region. These sensors were used to assess the glutamate uptake efficiency via challenging escalating concentrations of glutamate (10-200 µM) in astrocytes. Glutamate uptake was most efficient when astrocytes were exposed to 50 µM glutamate for 30min (50% net uptake). Efficiencies of glutamate uptake after 24-hour 100 µM CPF exposure were significantly diminished compared with the DMSO control.

The results shed light on the potential mechanisms by which CPF-induced disruption of astrocytic glutamate homeostasis may contribute to neurological damage and dysfunction. This work demonstrates the utility of electrochemical biosensing techniques for investigating the neurotoxicological impacts of environmental toxicants on specific cell types and neurochemical pathways. Further development of these analytical tools may aid in elucidating the complex relationships between astrocyte dysregulation, excitotoxicity, and neurodegenerative processes.
Developing Carbon Particles and WS2 Platelets Modified Gce Towards the Sensitive Electrochemical Detection of the Anticancer Drug Flutamide
Authors: Luo Yiran , Palanisamy Rupa Kasturi , Dempsey Eithne , Breslin Carmel B
Published: December 2024

The development of electrochemical sensors capable of detecting Flutamide is of great importance in biomedical research, environmental monitoring, and drug quality control. 1,2 In this study, a composite material consisting of Actinidia-derived Carbon Particles (CPs) and Tungsten Disulfide (WS2) was utilized to modify a glassy carbon electrode (GCE) and create a highly sensitive and reliable sensor for Flutamide. This was facilitated by the electrochemical reduction of Flutamide as shown in Scheme 1.

Scheme 1. Reduction of Flutamide

The Hydrothermally derived CPs are entwinned with hydroxyl, carbonyl, and amino groups, providing excellent support for the WS2 nanoparticles. Therefore, WS2/CPs nanocomposite acts as an efficient electroactive material on the GCE surface, thereby enhancing the sensitivity. The WS2/CPs electrochemical sensor exhibits outstanding selectivity and stability towards Flutamide detection, with a linear range of 1 nM to 104 µM, enabling the accurate detection of different Flutamide concentrations with high sensitivity. Moreover, the sensor has a low Limit of Detection (LOD) of 0.89 nM, indicating its ability to detect even trace amounts of Flutamide, further emphasizing its sensitivity.

The integration of CPs and WS2 provides an impressive sensor, with high stability, reproducibility, selectivity and a wide linear range, making it a reliable tool for various applications in biomedical research, environmental monitoring, and drug quality control. These advancements contribute significantly to the field of sensors and sensing technology.

Figure 1
Dissolution and Electrodeposition of Rare Earth Oxides within Acidic Eutectic Solvents
Authors: Khokhar Vaishali , Coskun Oguz Kagan , Gurkan Burcu E
Published: December 2024

The dissolution and separation of rare earth metals from their oxides represent a global demand due to the multifunctional applications of rare earths across various fields, necessitating expedited research in their extraction and recovery. The development of functional solvents such as ionic liquids and deep eutectic solvents solubilizing these metal oxides has gained interest in the recent years. In this study, various carboxylic acids as the active component in eutectic solvents are investigated in terms of the solubilization and electrodeposition of rare earths. Specifically, the solubility of lanthanum oxide reaching up to 0.38 M was achieved, as determined by the ICP-OES. A higher selectivity towards the lighter lanthanum oxide as compared to the heavier neodymium oxide was obtained, thus presenting a significant opportunity for selective dissolutions. Spectroscopic techniques including UV-vis molecular absorbance, ATR-FTIR, and NMR were employed to elucidate the speciation of the dissolved metal oxides and the solvation environment. Further, the electrodeposition of the solubilized rare earths directly in these media was studied on Cu to assess the ability to electrodeposit metals under benign conditions. This presentation will highlight electrolyte development for selective separation and direct utilization of the solubilized rare earths as elecrodeposits.
Mechanistic Insights into Hydrogen Transport through Metal Oxides Using Optical Microscopy
Authors: Thakkar Shreya , Sharifi Abdar Payman , Wilmer Christopher , McKone James
Published: December 2024

Catalytic materials that are also capable of hydrogen storage are attractive because they enable unique integrated reactor architectures for electroreduction processes. Redox-active transition metal oxides are a class of compounds that can be used for this purpose. For example, tungsten oxides undergo hydrogen insertion under negative applied potential to form tungsten oxide hydrogen bronzes, which in turn drive reductive hydrogen transfer reactions. Under these conditions, bulk hydrogen insertion sites react stoichiometrically while surface sites behave catalytically. For the design of better reactive hydrogen sorbents, it is imperative to understand the underlying mechanism of hydrogen insertion and transport through these materials. We are employing optical microscopy and molecular dynamics simulations to develop these insights.

We have designed a transparent electrochemical cell using commercial microscope slides, where one slide is coated with a thin WO3 film and two gold pads—one pad acts as the source of electrons for the tungsten oxide, which is the working electrode, and the other acts as the counter electrode. The reference electrode is placed outside the sandwich cell region with connection via a flowing electrolyte bridge. This sandwich cell is placed under the microscope to directly observe the formation of a coloration front in the WO3 films from greenish yellow to dark blue that indicates the formation of the HxWO3 (0 < x < 0.625) bronze. The color change is observed immediately at the point of contact between the film and the gold and progresses along the film with time. The use of a variable-wavelength monochromatic light source and an electron-counting camera enable us to quantify with high precision the optical density, which relates directly to the degree of (local) hydrogen insertion. Thus, the time-dependent movement of the coloration front can be measured experimentally and fit to a model to obtain physical parameters associated with a complex sequence of reaction-diffusion processes.

We are also working to extend these studies to other metal oxides and identify conditions under which the rates of hydrogen insertion and transport within the film are maximized. To aid in this process, we are leveraging molecular dynamics techniques to simulate H-transport through bulk oxides under varying conditions. The resulting insights are relevant for the design of advanced oxides that can activate, store, and deliver hydrogen to a wide variety of industrially relevant hydrogenation targets.
Shift in Electrochemical Pathway Under Forced Periodic Operation of Potential Applied Due to Catalytic Resonance Effect
Authors: Chandra Kanth Sidhanth , Rebrov Evgeny V
Published: December 2024

Sabatier's law is central to our understanding of catalysis. It states that the reactants will form reaction intermediates on the catalytic surface for a given catalytic reaction. Crucially, these intermediates must have an intermediate level of stability. If they are too stable, they will fail to decompose to form the product, and if they are too unstable, the catalyst will fail to activate the reaction1. The traditional strategy to design a catalyst for a reaction system is achieved by tuning the d-band filling of the catalyst (by making alloys, bimetallic, etc.) or by changing surface structure. Instead, this work demonstrates a constructive approach to shifting reaction pathways using the same catalyst. In the photo- and electrocatalysis, the shift in the reaction pathways (and selectivity) can also be achieved by operating the catalytic reactor using periodic modulation of one or multiple parameters around the steady state point2.

This study considers the electrochemical oxidation of formic acid over a Pt catalyst. This reaction follows a triple pathway: direct, indirect, and formate3. The indirect pathway forms CO as an intermediate, which strongly interacts with the catalyst surface. To further oxidise CO, an OH species needs to be adsorbed to form CO2, which requires a potential above 0.8 V vs RHE. Therefore in a steady-state galvanostatic operation, the reaction shows self-oscillation within a specific current range3.

This study uses a clean-electrolytic cell consisting of flame-annealed platinum wire as working and platinum mesh as a counter electrode with RHE as the reference electrode. The electrolytic cell is purged continuously with nitrogen, and gas is analysed using a gas analyser. The electrolyte consists of Suprapur 0.5 M H2SO4 and 0.2 M HCOOH. A sinusoidal voltage with a DC offset of 0.64 V vs RHE and amplitude of 0.26 V vs RHE was applied by varying frequency from 0 to 800 Hz. An enhancement in reaction rate by 1.94 times was observed at 800 Hz compared to steady-state operation at 0.9 V vs RHE. The I-V curve shows a qualitative enhancement towards the formate pathway compared to the indirect pathway above 600 Hz. The shift from indirect to formate pathway with a change in frequency above 600 Hz is further explained by the results from Electrochemical in situ Surface-enhanced attenuated total internal reflection infrared spectroscopy.

Reference

Chorkendorff, I. & Niemantsverdriet, J. W. Concepts of Modern Catalysis and Kinetics. Concepts Mod. Catal. Kinet. (2003). doi:10.1002/3527602658

Ellwood, Th., Živković, L., Denissenko Petr, Abiev, R.Sh., Rebrov E.V., Menka Petkovska, Processes 2021, 9(11), 2046; /doi.org/10.3390/pr9112046

Calderón-Cárdenas, A., Hartl, F. W., Gallas, J. A. C. & Varela, H. Modeling the triple-path electro-oxidation of formic acid on platinum: Cyclic voltammetry and oscillations. Catal. Today (2019). doi:10.1016/j.cattod.2019.04.054
Multi-Shell Copper Catalysts for Selective Electroreduction of CO2 to Multicarbon Chemicals
Authors: Xiao Yukun , Wang Lei , Chen Wei
Published: December 2024

Electrocatalytic CO2 reduction (CO2R) coupled with renewable electricity has been considered as a promising route for the sustainability transition of energy and chemical industries. However, the unsatisfactory yield of desired products, particularly multicarbon (C2+) products, has hindered the implementation of this technology. This work describes a strategy to enhance the yield of C2+ products formation in CO2R by utilizing spatial confinement effects. Our finite element simulation results suggest that increasing the number of shells in the catalyst will lead to a high local concentration of *CO and promote the formation of C2+ products. Inspired by this, we synthesize Cu nanoparticles with desired hollow multi-shell structures. The CO2 reduction results confirmed that as the number of shells increased, the hollow multi-shelled copper catalysts exhibited improved selectivity towards C2+ products. Specifically, Cu catalyst with 4.4-shell achieved a high selectivity of over 80% towards C2+ at a current density of 900 mA cm−2. Evidence from in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy unveils that multi-shelled Cu catalyst exhibits an enhanced *COatop coverage and the stronger interaction with *COatop compared to commercial Cu, confirming our simulation results. Overall, our work promises an effective approach for boosting CO2R selectivity towards value-added chemicals.
Exploring on Stainless Steel Based Electrodes for Oxygen Evolution Reaction Under Alkaline Electrolyte
Authors: Choi Yong-Wook
Published: December 2024

The clean energy, namely hydrogen, has been spotted lighted as a promising means for tackling down the problem of climate change. Alkaline Water Electrolysis (AWE) is identified as the representative method for obtaining hydrogen through sustainable way, because it needs only water and electricity (supplied from renewable energy sources such as solar light and wind). Especially, cheaper electrode materials like transition metal (Nickel) could be employed for both cathode and anode, whereas the other method (PEM-WE) should use only more expensive Pt-group materials.

Herein, we explored the possibility of stainless steel (SS) for anode under alkaline environment. SS based electrodes showed steady performance over the versatile range of current densities (from 10 mA/cm2 to 100 mA/cm2). These novel results would provide subsequent research with how to design for alternative electrode materials.

Figure 1
Enhancing Oxygen Evolution Reaction Performance Via Surface Fe Enrichment in Nife Oxalate Catalysts with KF
Authors: Ha Seungjoon , Kim Youngji , Lee Seunghwa
Published: December 2024

Enhancing the oxygen evolution reaction (OER) performance is essential for efficient hydrogen production from water using renewable electricity sources. In this study, we report the controlled synthesis of NiFe oxalate nanorods, facilitated by addition of potassium fluoride (KF) in the synthetic process. KF plays a crucial role, notably increasing the surface distribution of Fe (>80 at*) compared to syntheses conducted without KF. The optimal synthesis conditions, determined by OER activity, involved using 10 mM KF in an oxalic acid solution. This led to iron-rich NiFe oxalate-derived oxyhydroxides, which exhibited an overpotential of 226 mV at a current density of 10 mA cm-2. Operando Raman spectroscopy analysis was employed to probe the nature of active phases and reveal the origin of the improved OER activity.
MOF-Derived High Entropy Alloy Electrocatalyst with Low Amount of Noble Metal for Alkaline HER
Authors: Lim Seongje , Park Jong Hyeok
Published: December 2024

Although numerous researches for electrochemical hydrogen generation reactions have been conducted, they have the limitation of requiring the use of large amounts of several noble metal elements such as Pt, Ru, and Ir for hydrogen evolution electrocatalysts. In addition, there are increasing researches of high-entropy alloy electrocatalysts, which has many advantages for electrocatalysis like high stability, tunability of element composition and ratio, various active sites, etc., while their synthesis methods usually require harsh consition. In this research, we introduce CoNiCuMnRu/C high entropy alloy electrocatalyst for alkaline hydrogen evolution reaction, synthesized by using metal-organic frame work template as a precursor, followed by ion exchange method and pyrolysis. CoNiCuMnRu/C shows very low HER overpotential of only 19 mV at 10 mA cm-2 and high mass activity of 1.21 A mgRu
-1 at -0.07 V vs. RHE, succeeding commercial Ru/C and Pt/C. PDOS calculation shows Ni and Co sites act as active sites of water adsorption and ICOHP indicates insertion of low amount of Ru changes hydrogen adsorption feature of the high-entropy alloy electrocatalyst.
(Digital Presentation) Electrochemical Behavior of Ti(III) Complexes in the Chloride-Fluoride Melt
Authors: Vetrova Daria A. , Kuznetsov Sergey A
Published: December 2024

According to numerous studies the electroreduction of Ti(IV) fluoride complexes to the metal in chloride-fluoride melts occurs in two subsequent stages:

Ti(IV) + e- ↔ Ti(III) (1)

Ti(III) + 3e- → Ti. (2)

The redox reaction (1) in chloride-fluoride melts of different composition was thoroughly investigated in our previous works [1,2].

The aim of the present investigation was the determination of reaction (2) kinetic parameters such as: coefficients of transfer, diffusion coefficients of Ti(III) and standard rate constants of charge transfer, in the (NaCl-KCl)equimol.-NaF(10 wt.%)-K2TiF6 melt. Another goal was to study the influence of the working electrode material on the kinetics of the discharge reaction.

[1] D.A. Vetrova, S.A. Kuznetsov. 2021. J. Electrochem. Soc., 168: 036517.

[2] D.A. Vetrova, S.A. Kuznetsov. 2023. J. Electrochem. Soc., 170: 086503.
Study on Doping Strategies to Improve the Stability of Ni-Rich Layered Cathodes for Electric Vehicles
Authors: Umirov Nurzhan , Nuroldayeva Gulzat
Published: December 2024

Lithium-ion batteries (LIBs) with layered-type cathodes, particularly Li[NixCoyMn(1-x-y)]O2 (NCM) and Li[NixCoyAl(1-x-y)]O2 (NCA), are considered frontrunners for powering next-generation electric vehicles (EVs) due to their high energy density potential. However, a critical challenge lies in achieving this potential – increasing the nickel (Ni) content (x>6) in these cathodes leads to decreased cycling lifetimes and lower thermal stabilities, hindering their widespread use. Researchers are actively exploring the strategy of doping transition metals (Al, Mg, Ti, W, etc.) into Ni-rich layered cathodes to enhance their stability [1]. These efforts can be broadly categorized based on the stage at which the dopant is introduced:

Dopant addition during precursor co-precipitation. This approach involves incorporating the dopant element alongside the precursor cathode active material during the initial synthesis step. Here, the dopant ions are believed to integrate into the crystal lattice, potentially modifying the material's structure and influencing its electrochemical performance.

Dopant addition during calcination step. In this method, the dopant is introduced after the precursor is formed, typically during the high-temperature calcination process. The dopant may coat the cathode secondary particle surface or interact with the lattice at grain boundaries, potentially improving structural stability and mitigating performance degradation.

By comprehensively investigating these two primary doping strategies, we aim to optimize the stability of Ni-rich layered cathodes, paving the way for their successful application in high-performance EV batteries. Herein we determine the optimal doping path to achieve the best balance between energy density, cycling life, and thermal stability for next-generation EVs.

Acknowledgements

This research was funded by the project АР13068160 “Development of the high energy cathode materials for Electric Vehicle application using domestic raw materials from local silicate nickel ore” from the Ministry of Science and Higher Education of the Republic of Kazakhstan.

References

[1] Cui, Z., Li, X., Bai, X., Ren, X., & Ou, X. (2023). A comprehensive review of foreign-ion doping and recent achievements for nickel-rich cathode materials. Energy Storage Materials, 57, 14-43.
Thermal Treatment As a Key Factor for Obtaining Top-Grade Core-Shell NMC Cathode Materials
Authors: Grygiel Michał , Buchberger Dominika , Winkowska-Struzik Magdalena , Firlej Natalia , Struzik Michal , Czerwiński Andrzej
Published: December 2024

Lithium-ion batteries (LIBs) continue to be one of the main technologies in the energy storage industry, powering various devices from portable electronics to electric vehicles. However, to meet the growing demand for higher energy density, longer cycle life, and improved safety, there is a pressing need for innovative electrode materials[1]. In this presentation, we approach the development of an advanced positive electrode material for LIBs based on a core-shell structure, utilizing lithium nickel manganese cobalt oxide (NMC) with a nickel-rich core and a low-nickel shell.

The core-shell structures present a promising route for simultaneously enhancing the performance and stability of LIBs[2]. By incorporating a nickel-rich core, it is possible to leverage its high capacity, while the low-nickel shell ensures reducing undesirable side reactions, such as electrolyte decomposition and transition metal dissolution[3], thereby enhancing safety and longevity of the battery.

Our research focuses on electrochemical evaluation of various NMC compositions to determine the best materials for the core and the shell, focusing on specific capacity, rate performance and cyclability. As different stoichiometries of NMC usually require distinctive thermal treatment conditions[4,5], a careful examination is needed in order to ensure proper crystal structure of both the core and the shell. In that regard we conducted a set of in situ and ex situ XRD studies on pristine materials. In combination with electrochemical assessment these results enabled us to match high-capacity nickel-rich NMC for the core with enhanced-stability low-nickel variants for the shell in terms of the best possible compatibility of thermal treatment conditions in mind.

This allows us to further study the core-shell NMC materials characterized by both satisfactory electrochemical performance and enhanced cyclic stability. This approach opens the possibility to develop LIBs with higher energy density, prolonged cycle life, and enhanced stability, crucial for meeting the evolving demands in the advancing energy storage sector.

This work was funded by the National Science Center in Poland through the Sonata 17 programme (No.
UMO-2021/43/D/ST5/03094).

[1] M. Li, J. Lu, Z. Chen, K. Amine, Adv. Mater. 2018, 30, 1800561.

[2] H. Peiyu, Z. Hongzhou,Z. Zhongyue, Z. Lianqi,X. Xijin, J. Mater. Chem. A, 2017, 5, 4254–4279

[3] Li, T., Yuan, XZ., Zhang, L. et al. Electrochem. Energ. Rev. 3, 43–80 (2020).

[4] Noh, H. J., Youn, S., Yoon, C. S., Sun, Y. K., J. Power Sources 233, 121– 130 (2013).

[5] Zheng, J., Yan, P., Estevez, L., Wang, C, Zhang, J. G., Nano Energy 49, 538– 548 (2018).
Thermal Stability and Performance of Li-Ion Batteries at Elevated Temperatures: Separator Effects
Authors: Romero Cameron Taj , Strickland David Allen , Bachman J. Chris , Keating Michael , Biddinger Elizabeth J. , Messinger Robert J. , Jones John-Paul , West William C
Published: December 2024

The performance and safety of lithium-ion batteries (LIBs) are significantly influenced by the stability and integrity of their components that have been optimized for a limited temperature range (ca. 0 to 40°C). At elevated temperatures, conventional LIBs exhibit issues such as rapid capacity fade, compromised electrolyte stability, and an increase in internal resistances. With the push towards net-zero emissions, it is imperative that suitable materials and cell designs be identified to allow rechargeable battery integration into operations with temperatures as high as 100°C for applications such as space exploration, drilling equipment, and automotive technologies.

In our presentation, we will report that a design of experiment (DOE) study examining several independent variables and interactions of variables in the cell design revealed that the standard polyolefin separator is associated with both decreased Coulombic efficiency and increased variability in cycling performance at elevated temperatures relative to non-polyolefin (e.g. polyimide) separators. In a separate study, electrochemical data were obtained by cycling coin cells at 100oC, varying only the separator (Fig. 1). After the first 20 cycles, the polyimide cells maintained a higher specific capacity relative to the polyolefin cells.

Figure 1. Specific capacity vs. cycle number for NMC111/graphite coin cells with Polyimide and Polyolefin separators

The nature of the separator alterations from a chemical and electrochemical perspective will be presented, which will provide valuable insight into the critical role of separators in battery design while simultaneously offering alternative materials for operations as high as 100°C.

Figure 1
Optical Chlorobasicity Determination in Molten ZnCl2-KCl Via UV-Vis Spectroscopy
Authors: Buttice Kailee Joy , Couet Adrien , Gakhar Ruchi , Yang Qiufeng
Published: December 2024

The goal of this research is to construct a basicity scale for molten halide salts to quantitively determine the effect of salt composition on structural material corrosion. Optical basicity is a quantity derived from the UV-Vis spectra of p-block transition metal ions dissolved as probes in a molten salt and is primarily dependent on the amount of free halide within the melt. The outer orbitals of the probe ions are compacted through interaction with halide anions within the salt, lowering the s-p excitation energy and thus increasing optical basicity. Preliminary studies on bismuth as a probe in the ZnCl2-KCl system have been conducted and produced results adjacent to the AlCl3-KCl system that has historically been studied in the context of optical basicity. While the peak wavelength as a function of composition curve was not linear, basicity itself may also not be linear related to salt composition. It was found that due to the chloroacidity offered by the ZnCl2 in the melt, lower oxidation states of bismuth (Bi+ and [Bi5]3+) are stabilized and that increasing the ratio of ZnCl2:KCl, as well as increasing the temperature of the melt, resulted in a decreased wavelength of peak absorption for the Bi+ electronic transition. This is evident of greater chloroacidity—there are fewer chloride ions available to offer electron density and decrease the energy barrier of bismuth electronic excitation. The tendency of Zn to form tetrahedral complexes, occupying more Cl- in the process, in ionic liquids is partially to blame, as well as the increased ionicity and decreased network-forming behavior at elevated temperatures. Bi+ can therefore also serve as a probe for chlorobasicity for this salt system. Further investigation of this system and other chloride/fluoride salts as well as studies on Tl and Pb as probe ions shall be performed in future studies to determine the best optical basicity probe for each molten salt studied.
Electrochemically-Assisted Solvent Extraction: A Novel Approach to Rare Earth Element Separations
Authors: McDonald Declan , Spigel Alden , Wozny Jacob , Hill Caleb M. , Di Bona Kristin R.
Published: December 2024

Rare earth elements (REEs), which consist of the lanthanide series, Sc, and Y, are considered “critical” materials due to their important uses in many industries (energy, electronics, etc.), yet are challenging to separate due to the very similar chemical properties between them. Current industrial-scale REE separations technologies are based on solvent extraction schemes which require 100s of steps and produce large amounts of undesirable chemical waste, largely due to the inability of existing extractant systems to discriminate between individual REEs. These environmental and economic factors have severely limited the development of U.S.-based REE separations facilities. Here, we present studies of an alternative electrochemical approach to solvent extraction which leverages the unique properties of ionic liquids (ILs). Cyclic voltammetry studies will be presented which demonstrate the controllable transfer of REE ions across aqueous-IL interfaces and enable key thermodynamic parameters describing separation to be rigorously evaluated. The feasibility of practical REE separations using this approach has been demonstrated via bulk electrolysis studies and efforts by Wyonics and the University of Wyoming to develop and commercialize environmentally- and economically-favorable processes for the extraction, separation, and recovery of individual REEs from REE-containing sources.
Updates on Molten Salt Ferrofluid
Authors: Halstenberg Phillip , Kim Ellie , Nguyen Dianna , Maltsev Dmitry S. , Gilbert Dustin , Dai Sheng
Published: December 2024

Magnetic molten metal chloride salts were synthesized via addition of magnetically susceptible nanoparticles to salt matrices to create a molten salt ferrofluid. Various sizes of nanoparticles composed of cobalt were added to 57% NaCl – 43% MgCl2 and 45% KCl – 55% ZnCl2 salt mixtures. Mixtures were examined for susceptibility to an external magnetic field between 25 °C – 800 °C utilizing magneto – thermogravimetric experiments and vibrating sample magnetometer experiments. The materials were further examined using a combination of microscopy, spectroscopy, solubility analysis, and diffraction measurements. All sizes and concentrations of metallic cobalt nanoparticles demonstrated a degree of chemical stability and continued interaction with an external magnetic field between 25 °C – 800 °C when dispersed in NaCl – MgCl2 and KCl – ZnCl2 mixtures. Once in the molten state, the measured magnetic interaction between the molten ferrofluid and external magnetic field increased; indicating the ferrofluid becomes more magnetic as the temperature increases.