bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced Graphene Oxide Carbon Additives of Alpha-MnO2 Cathode for Enhanced Capacity and Energy Density in Aqueous Zn Ion Battery
Authors: Byun Segi , Baek Jueun , Ahn Yunhee , Kim Seulgi , Lee Dongju , Yoo Jungjoon
Published: December 2024

Rechargeable aqueous zinc ion batteries (AZIBs) have recently attracted great attention in large-scale energy storage system due to their low cost, high stability and eco-friendliness by using aqueous electrolyte system. However, the development of AZIBs as a commercialized technology has been impeded by the absence of cathode materials demonstrating robust electrochemical performance, particularly in terms of specific capacity and stability. Manganese oxides (MnO2) have emerged as a promising cathode material, offering high specific capacity and potential window, yet they face challenges of low electrochemical stability and electronic conductivity. To address these issues, the effects of conductive carbon additives on the electrochemical properties of MnO2-based cathodes in AZIBs were investigated. Specifically, we examine the effect of different carbon additives, including carbon black, carbon nanotubes (CNTs), and reduced graphene oxide (rGO), on the mass loading and capacity behavior of the active material in the electrode. Through material and electrochemical characterization, we compare the stability, capacity and electrode kinetics of MnO2-based cathodes in AZIB as a function of carbon additive type and proportion. The experimental findings suggest an optimal conductive carbon composition that significantly boosts the energy density and stability of the manganese oxide-based cathodes, offering a strategic approach to overcoming the limitations of current AZIB technologies and paving the way for their application in large-scale energy storage systems.

This work was supported by a National Research Council of Science & Technology (NST) grant by the Korean government (MSIT) (No. CAP22071-000).
Development of a Cell-Based Pre-Transfer Learning Model and an Electrochemical Analysis-Based Remaining-Useful-Life Prediction Model for Large Scale Battery Pack in Fast Charging Condition
Authors: Park Jinhyeong , Kim Tae-hoon , Lee Hongjong , Choi Jae Young
Published: December 2024

The California ACC2 to be established in 2026 specifies the accuracy and warranty period for state-of-health (SOH). The regulations newly established that, unlike electric vehicles BMS information on the current market trend, consumers must mark their vehicles without additional specialized diagnostic equipment, and recall will be made if the SOH and actual measurements of randomly selected vehicles do not meet the accuracy of less than 5%.

In this paper, through the previous literature analysis, it was confirmed that the algorithm is required to be verified based on actual road driving data, not verification in the experimental stage performed in the LAB scale, and in order to efficiently estimate the battery state based on the SW technique specified in ACC2, it was confirmed that a methodology that can be applied in real-time situations is required to minimize the basic test data required for state diagnosis. And then, the estimated SOH in real-time simulation is utilized for learning data set for predicting the RUL using transfer learning based on LSTM (Long short term memory) and cell scale aging data. Therefore, in this paper, the data of the electric vehicle that was actually driven is acquired as shown in the figure and the estimated SOH is estimated based on the data.

A study was conducted to compare and evaluate the RUL (Remaining-useful-life) value of the actual battery pack by removing the battery pack of the driven vehicle and to verify and analyze it by comparing it with the predicted RUL. In addition, in order to overcome the problem of the partial current integration method applicable in a parking situation, a methodology that can be integrated with a model-based algorithm using electro chemical signal is proposed, and for this purpose, the characteristics and reference points of the test data-based battery are proposed.

[Acknowledgements]

This paper was conducted with the support of Ministry of Trade, Industry and Energy in 2024 (P0021883, Implementation of on-board grade estimation for EV battery using database and verifying re-use applications with used batteries)

Figure 1
A Study on the Correlation with Charging Characteristics According to the Charge & Discharge Life of Lithium Ion Battery Cells and a Method for Analyzing the Remaining Life
Authors: Lee Hongjong , Kim Tae-hoon
Published: December 2024

In this paper, we propose a method to analyze the remaining life of lithium-ion battery cells by utilizing the deterioration characteristics caused by the application of charge/discharge current. The method of checking the remaining life of a battery cell through charging and discharging with an SOC 0% to 100% may be the most accurate, but it is impossible to check the battery applied to an actual vehicle or application. Therefore, a life evaluation environment was constructed using two lithium-ion battery cells, and the deterioration characteristics of battery cells according to temperature were analyzed through the application of life patterns at room temperature and high temperature and reference performance tests at regular cycle units. Using the analyzed results, we would like to suggest a method to analyze the remaining life in the BMS (Battery Management System) applied to the application.

[Acknowledgements]

This paper was conducted with the support of Ministry of Trade, Industry and Energy (20024923)
Carbon-Based Materials As Negative Electrodes in Sodium-Ion Batteries
Authors: Chmielniak Marta , Krajewski Michał , Grabowski Oskar , Winkowska-Struzik Magdalena , Czerwinski Andrzej
Published: December 2024

Nowadays effective energy storage, especially batteries, plays a crucial role in technology development. Due to the high abundance and low cost of sodium, sodium-ion batteries are promising substitutes for widely used Li-ion cells. Graphite-based materials are commonly used as a negative electrode in lithium systems. However, sodium ions have a larger ionic radius compared to lithium ones, and also the energy of intercalation of graphite by Na+ is higher than by Li+ [1]. Therefore, it is necessary to use different types of carbon- based materials with greater interlayer spacing, which can be achieved through increased structural disorder. These materials could be obtained through the thermal processing of polymers [2]. Additionally, due to their high porosity, the adsorption of sodium ions is more efficient. All these properties enhance the specific capacity of negative electrodes in sodium- ion systems.

As a result of thermal processing, we obtained porous carbon-based materials. The synthesized powder's electrochemical characteristics have been examined using three-electrode Swagelok®-type cells. Slurry-coated electrodes with carbon-based materials were used as the working electrode, while sodium metal was used as the reference electrode and the counter electrode.

Sodium-ion systems were investigated in a high-rate test, with a charging current of 1 C and discharge current rates varying from 1 C to 10 C. Even at the highest discharge current rate, the batteries retained a high percentage of the first-cycle specific capacity.

The cycle stability of sodium-ion systems was also examined. After 50 cycles of charging/discharging at a current of 1 C, the specific capacity did not decrease significantly as compared to the specific capacity of the first cycle.

Furthermore, the cyclic voltammetry behaviour of these systems was also investigated. Although the two signals were not well separated, it was evident that two electrochemical phenomena were present: diffusion of sodium cations in the carbon matrix and sodium adsorption on the carbon surface.

The synthesised carbon-based porous materials demonstrated stability during the charging and discharging of sodium-ion batteries. The implementation of these products in sodium-ion technology could be helpful during the process of commercialization of such energy storage systems.

Acknowledgements: This work was supported by The Polish National Centre of Science through a research grant 2021/43/D/ST5/01220 entitled “High-voltage sodium-ion batteries based on exfoliated graphite electrodes”.

Literature:

[1] Y. Liu et al. „Origin of low sodium capacity in graphite and generally weak substrate binding of Na and Mg among alkali and alkaline earth metals”, PNAS USA 113 2016

[2] T. Zhang et al. „Recent Advances in Carbon Anodes for Sodium-Ion Batteries”. Chem. Rec. 22 2022
Universal Neural Network Potential Driven Molecular Dynamics Study of CO2 and O2 Evolution at the Ethylene-Carbonate/Charged-Electrode Interface
Authors: Horibe Motoki , Tanihata Naoto , Takeda Hayami , Nakayama Masanobu
Published: December 2024

Lithium-ion batteries are currently used in large power sources such as automobiles, for which durability and safety are required. However, LIB suffers from degradation such as CO2 generation from electrolyte decomposition and O2 emission from cathode materials. These side reactions and gas generation can cause serious problems leading to ignition and explosion. It is important to understand how reactions occur at the interface during charging to generate CO2 and O2.

This reaction at the cathode/electrolyte interface has been studied by various experimental and computational methods. In particular, density functional theory (DFT) simulation studies are effective in clarifying the decomposition process of the electrolyte at the atomic level. However, DFT calculations for liquid electrolytes are computationally demanding, since the number of molecules are prone to be large when considering molecule-molecule interaction1. To solve, we apply universal neural network potential (UNNP) molecular dynamics (MD) simulations to the reaction at the electrolyte solution / solid electrode interface.

In this study, we focused on LixCoO2 (0≤x≤1) and LixNiO2 (0≤x≤1) as cathode materials, and ethylene carbonate (EC) as the electrolyte solvent. The model consists of Li180(1-x)Ni180O360 (Li180(1-x)Co180O360) slab and 100 EC molecules. After the structural relaxation calculations, MD calculations were performed for a 500 ps in a canonical (NVT) ensemble with a time step of 1 fs. Temperatures were 373 K and 473 K, which are below the boiling point of EC.

In LiCoO2, no decomposition of the electrode or electrolyte was observed. On the other hand, CO2 was generated in the MD calculation for LiNiO2. The generation process (3 steps) is shown below.

(1) Hydrogen dissociation/desorption from EC molecules.

(2) Combination of the ethylene group carbon of the EC molecule, from which hydrogen dissociation has occurred, with the oxygen on the cathode surface.

(3) Ring-opening between the ethylene group carbon of the EC molecule and oxygen, resulting in CO2 generation.

The O2 generation phenomenon was observed to occur in the following three steps as shown in Figure 1.

(1) Ni moves to the Li layer to form NiO4 tetrahedron. (Figure 1 (a) → (b))

(2) Oxygen dimer is formed by the bonding of NiO4 tetrahedron and NiO5 polyhedron derived from NiO6 octahedron. (Figure 1 (c))

(3) Oxygen dimer is released. (Figure 1 (d))

Technical details will be presented, in particular on CO2 evolution, at the poster session.

References

1. Okuno et al. The Journal of Physical Chemistry C 2019 123 (4)

Figure 1
Incorporation of Lithium Ultra-Phosphate into Li-Si-S Glass Compositions
Authors: Lyle Cody , Torres Victor Manuel , Martin Steve
Published: December 2024

Development of a solid electrolyte in solid-state batteries has been of increasing focus in recent years. A promising contender is glassy solid electrolytes due to their tunable properties and ease of synthesis. Mixed oxy-sulfide glasses (MOS) glassy solid electrolytes (GSEs) have been shown to exhibit high electrochemical stability, high ionic conductivity, and easily synthesized. In this MOS glass series, we are substituting Li0.67PO2.83 with SiS2 to form the glass series of 0.58 Li2S + 0.378 SiS2 + 0.042 Li0.67PO2.83. Differential scanning calorimetry (DSC) was used to determine the glass and crystallization temperatures. Electrical impedance spectroscopy (EIS) was taken to understand and measure the Li+ ion conductivity. To identify the structure in these glasses, we utilized Fourier transform infrared (FTIR) and Raman Spectroscopy. The results show that through incorporation of oxides into sulfides there is an improvement in the properties of these materials.
Optimization of Recycling Process of Layered NCA Material using Li+-H+ Exchange Reaction
Authors: Ariyoshi Kingo , Matsushita Chisa , HIrota Jo
Published: December 2024

In recent years, recycling of spent batteries is becoming an urgent issue due to the increasing popularity of vehicles. In particular, the sustainable and competitive recovery of rare metals such as Li, Co, and Ni from positive electrode materials is important from the viewpoint of resource depletion and environmental preservation. In this study, we propose a novel recycling method of layered positive electrode materials for separating transition metals and lithium by treating with oxidant solution.

The process proposed in this study utilizes a Li+-H+ exchange reaction (Fig. a), in which Li ions in the layered materials are replaced with H+ in the solution with preserving the structural framework constructing of transition metals and oxygens. Because the recycling process can be classified into one of the direct recycling, there are many advantages compared with hydrometallurgy; small amount of oxidizing agents, only single step for separation of metals, and distinct separation of metals (transition metals as a precipitation and Li ions in the aqueous solution).

Fig. b shows our preliminary results on the recycling of LiNi0.88Co0.09Al0.03O2 (NCA) via the Li+-H+ exchange reaction. By immersing NCA in a 0.1 M of K2S2O8 aqueous solution, the XRD peaks belonging to NCA became weak, and new peaks belonging to NiOOH appeared and grew with increasing the digestion time. This means that Li ions in NCA were exchanged with H+ in the solution during the digestion. Furthermore, heating thus obtained NiOOH with Li source provided virtually the same XRD pattern as the pristine NCA, indicating that recycling of NCA is possible by utilizing Li+-H+ exchange reaction.

To analyze kinetically the exchange reaction for optimization of the recycling process, the immersion experiments were performed with varying temperatures. The degree of exchange reaction was determined from the ICP measurements of the solution after immersion. The exchange reaction was accelerated with increasing the temperature. Plotting the logarithm of the amount of lithium extracted against digestion time showed a linear relationship at all temperatures (Fig. c), indicating that the exchange reaction obeys a first-order reaction.

In this presentation, we will discuss the effects of oxidants on the Li+-H+ exchange reactions and resynthesis of NCA.

Figure 1
Electric Vehicle Battery Degradation: Effects of Mixed Fast and Slow Charging on Commercial NCA Cells
Authors: Morin Hannah , Whitacre Jay F
Published: December 2024

Battery diagnostic studies are commonly done using one charging rate for the entirety of cycling, and so do not study the effects of combined rapid and slow charging. To address this gap, this study investigates the effect of mixing 2C charging and C/6.8 charging (~Level 2 charging) during the cycling of commercial LiNi0.8Co0.05Al0.15O2 (NCA) batteries in a way that mimics an aggressive use case of EV fast charging (~150kW) and highway driving (C/6 discharge). Electrochemical and materials properties of the cells during and after cycling were investigated using cycling data, differential voltage analysis (dQ/dV), SEM and XRD in order to propose possible degradation mechanisms. An analysis of SOH and cell resistance over time will be presented. The findings of this study suggests that cells cycled under mixed fast charging conditions degrade differently than those cycled under a symmetrical and consistent C/6.8 charge rate, supporting the need for consumer behavior to inform accelerated aging studies. It suggests that there is a nonlinear relationship between both discharge and fast coulombic throughput at failure. And it suggests that the observed knee-point degradation does not have an underlying mechanism related to a cathode bulk phase change to spinel, which provides a potential opportunity for direct recycling of NCA cathodes.
Beneficial Impact of Selenate/Selenide Additives on the Performance and Longevity of the Iron Electrode for Alkaline Batteries
Authors: Rajan A Sundar , Tomar Yeshvi , Maniyanganam Ahamed Irshad , Mitra Debanjan , Narayan Sri , Prakash G. K. Surya
Published: December 2024

The alkaline iron electrode stands out as a cost-effective and robust negative electrode option, particularly suited for large-scale energy storage applications. During discharge, iron undergoes oxidation transforming into iron dihydroxide (Fe(OH)2). Iron dihydroxide is insulating in nature which inhibits electrode discharge. The iron sulfide (FeS) is introduced as an additive to the iron electrode which serves to establish a conductive matrix, facilitating electrode discharge. However, the longevity of iron electrodes is constrained by the iron sulfide (FeS) additive. Through repeated cycles of charge and discharge, the sulfide ions gradually deplete from the electrode, undergoing slow dissolution and irreversible oxidation to sulfate. We have investigated alternative additives to iron sulfide, with iron selenide (FeSe) emerging as a promising candidate. Experimental findings reveal that iron selenide offers comparable benefits to sulfides while exhibiting reversible oxidation and reduction. Through extensive electrochemical investigations of selenate/selenide behavior in alkaline electrolytes and repeated cycling of battery electrodes, we demonstrate the superior longevity of iron selenide over iron sulfide additives. Our results indicate a remarkable 96% capacity retention in iron electrodes containing FeSe additives up to the 1450th cycle, as shown in Figure.

Figure 1
Void-Suppression at Low Stack Pressures Using a Microstructurally Engineered Anode
Authors: Veeraraghavan Vijay D. , Lo Chiung-Yuan , Murali Sriram S. , Li Andrew B. , Fincher Cole D. , Viswanathan Venkat , Chiang Yet-Ming
Published: December 2024

Solid-state batteries (SSBs) with a Li+ working ion promise a step change in specific energy and safety by using less-reactive solid-state electrolytes (SSEs) in contact with Li metal. However, commercialization of SSBs has been hindered by low specific power due to contact loss at solid-solid interfaces. Voids nucleate and grow at the solid-solid interface between Li metal and the SSE, increasing interfacial resistance. It is hypothesized that during charging ionic current intensification at this interface, which magnifies with increased contact loss, can increase the driving force to nucleate Li dendrites which grow until a short circuit causes cell failure.1

A common workaround for these anode/SSE contact loss issues is to use high uniaxial stack pressures (>1 MPa) applied normal to the planar interface; one theory is that mechanical deformation of Li metal via power-law creep suppresses void growth.2,3 This approach negates one of the proposed benefits of SSBs: high stack pressures require additional mechanical fixturing components which reduces the cell specific energy.

We introduce a microstructured Li metal anode which, while operating in contact with Li6.75La3Zr1.75Ta0.25O12 (LLZTO) SSE at low stack pressures (0.15 MPa) and at room temperature, achieves stable Li stripping for areal capacities more than 10 times that of a lithium control group at current densities up to 1 mA cm-2. We will discuss the mechanisms enabling this suppression of contact loss using data from 3-electrode (Li reference) galvanostatic tests allowing contributions from the stripping and plating electrodes to be deconvoluted.

References:

[1] Raj, V.; Venturi, V.; Kankanallu, V. R.; Kuiri, B.; Viswanathan, V.; Aetukuri, N. P. B. Direct Correlation between Void Formation and Lithium Dendrite Growth in Solid-State Electrolytes with Interlayers. Nat. Mater.
2022, 21 (9), 1050–1056.

[2] Wang, M. J.; Choudhury, R.; Sakamoto, J. Characterizing the Li-Solid-Electrolyte Interface Dynamics as a Function of Stack Pressure and Current Density. Joule
2019, 3 (9), 2165–2178.

[3] Fincher, C. D.; Ojeda, D.; Zhang, Y.; Pharr, G. M.; Pharr, M. Mechanical Properties of Metallic Lithium: From Nano to Bulk Scales. Acta Mater.
2020, 186, 215–222.

Acknowledgements:

Funding is gratefully acknowledged from Morphogenic Interfaces, Defense Advanced Research Project Agency, contract HR00112220032. V.D.V. acknowledges funding from the National Science Foundation Graduate Research Fellowship Program. C.Y.L. acknowledges funding from the Chiang-Chen Overseas Fellowship. C.D.F acknowledges funding from the Department of Defense National Defense Science and Engineering Graduate Fellowship.
Improvement in Rate Capabilities of Hybrid Cathodes with through-Holed Layers of Cathode Material and Activated Carbon on Each Side of a Current Collector in Lithium-Ion Batteries
Authors: Yamada Mitsuru , Fukunishi Mika , Matsumoto Futoshi
Published: December 2024

This study was conducted to improve the rate capability and cyclability of cathodes for lithium-ion batteries (LIBs) with hybrid cathode structure. Through-holed LIB cathode material and activated carbon layers formed on each side of a current collector were drilled with a picosecond pulsed laser beam for preparing the cathode structure (Figure). The hybrid cathodes exhibited excellent rate capabilities of 93% capacity retention at 100 C. The results were dependent on the weight percentage of the activated carbon relative to the total weight of the active materials and on the difference in discharge/charge voltages between the LIB cathode and activated carbon materials. The cathode could have cycle stability at 50 C during 100 cycles. The performance characteristics of the hybrid cathode, the through-holed and nontreated LIB cathodes and the nontreated activated carbon cathodes were compared in a Ragone plot. In the plot, the hybrid cathode was located in the region where conventional through-holed and nontreated cathodes could not be located.

Figure 1
Corrosion Behavior of Al-Zn Alloys Fabricated By Spark Plasma Sintering
Authors: Chung Euihyuk , Nishimoto Masashi , Tokuda Shimpei , Nishida Yoshikatsu , Muto Izumi
Published: December 2024

Hot-Dip Al-Zn plated steel sheets are essential materials for societal infrastructure, utilized in construction materials and conveying equipment. To further enhance the durability, a balance between the dissolution resistance of the plating layer and sacrificial corrosion protection for the base steel is crucial. In this study, we fabricated Al-Zn alloys, to analyze the influence of the microstructure refinement on the dissolution behavior.

Using the planetary ball milling, powders of 65at%Al-Zn,75at%Al-Zn and 50at%Al-Zn were prepared. Powders were sintered by plasma sintering. As a comparative reference, a Hot-Dip 55mass%Al-Zn steel was prepared. To investigate corrosion behavior, immersion potential, polarization curves, and galvanic current measurements were conducted using the three-electrode method.

The sintered bodies constitute a complex microstructure consisting of nano-scaled Al-rich and Zn-rich phases. Measurements of the immersion potential revealed that the sintered bodies exhibited dissolution behavior different from the conventionally used Al-Zn plating layer. The base steel was protected after the galvanic current measurements, as observed through surface analysis.
Effect of N on Pit Initiation at MnS in Type 304 Stainless Steel
Authors: Tsuchiko Yusuke , Nishimoto Masashi , Muto Izumi
Published: December 2024

N is known as an element that improves the pitting corrosion resistance of stainless steels, but its mechanism of action is unknown. Since N is not a resource constraint and the addition of N does not reduce toughness in FCC, it is important to clarify the effect of N on pitting corrosion resistance of austenitic steels and to find a means to utilize N more effectively from the viewpoint of resource conservation in the production of corrosion-resistant steels. In this study, the effect of N on the occurrence of pitting corrosion was analyzed by electrochemical measurements on Type 304 stainless steel containing MnS.

Type 304 stainless steel containing 0.120 mass% N was used as a sample, and Type 304 stainless steel containing 0.005 mass% N was used as a comparison material. Each sample was heat treated at 1100°C for 30 minutes and then water cooled.

After heat treatment, the specimens were polished with 1 µm diamond paste, and inclusions were observed using optical microscopy and SEM-EDS.

Polarization curves were measured under 0.1 M NaCl solution at pH 6.0 and water temperature of 25°C, to compare pitting potentials. After the measurements were made, the areas where pitting corrosion was occurring were observed under an optical microscope.

For each steels, it was confirmed that pitting corrosion occurred starting from MnS inclusions.

The N-doped steels showed a higher pitting corrosion potential than the steels containing little or no N.
Development of a Universal Material Characterization, Evaluation and Estimation System via Microstructure Construction
Authors: Huang Yihui , Kawada Tatsuya , Sato Kazuhisa
Published: December 2024

In recent decades, advancements in material-scanning technologies have enabled detailed acquisition of microstructural data, yet direct integration of this data into simulation models remains challenging. This study develops a system that utilizes scanning electron microscope (SEM) micrographs to construct a 2D spatial map, which categorizes microstructural attributes. Employing the Marching Cubes algorithm, we create the contours and shapes of grain clusters based on consistent grey values, facilitating the precise generation of grain areas in simulation software. This generated model is then applied to simulate a uniaxial tensile test, revealing irregular principal stress distributions along grain boundaries and notable stress concentrations at void-grain interfaces. These results emphasize the system’s efficacy in providing precise material characterization, evaluation, and estimation. Additionally, the system accommodates further refinements, such as incorporating crystal orientations and conducting analyses like creep deformation and electrical property evaluation. Ultimately, this approach supports a comprehensive pipeline for material design, testing, analysis, and simulation, thereby enhancing the potential for targeted material improvements.

Figure 1
Effect of Charge during Current Recovery on Morphology of Anodic Porous Alumina Film/Substrate Interface
Authors: Inagawa Kazuki , Hagiwara Kenta , Asoh Hidetaka
Published: December 2024

Porous-type anodic oxide film, so-called anodic porous alumina, which is formed by the anodization of aluminum, is a typical self-ordered nanoporous material. It is often called a nanochannel or nanohole structure depending on the dimensions of porous-type anodic oxide film. When the formation voltage is suddenly dropped during anodization, the current gradually recovers after a period of almost no current flow and becomes steady state. In other words, the specimen is re-anodized at the new voltage. This phenomenon is known as the current recovery. The morphology of the pore base (i.e., anodic porous alumina film/substrate interface) is affected by the change in voltage. Using this technique, branched channels with various morphology have formed by lowering the formation voltage suddenly. The tree-like morphology of branched channels can be applied to fabricate unique structures such as Y-junction nanodevices. In this study, we investigated the relationship between the morphology of pore branching in anodic porous alumina and the charge consumed during the current recovery from the point of view of decorativeness. Anodic porous alumina films with a thickness of approximately 10 µm were prepared in sulfuric acid by constant current anodization. After that, the voltage was dropped to a predetermined voltage in the same electrolyte. The degree of pore branching in the anodic film, which depended on the charge during the current recovery, was systematically evaluated by SEM observation of the anodic film/substrate interface after removal of the anodic film.
Structural and Electronic Modification of Electrocatalyst By Se Doping for Hydrogen Evolution Coupled Selective Electrooxidation of Ethylene Glycol to Glycolic Acid
Authors: Jang Daehee , Park Minseon , Maeng Junbeom , Seo Min Ho , Kim Won Bae
Published: December 2024

Chemical reforming by electrochemical reaction has attracted great attention due to mild reaction condition and ease of control. As the raw materials for electrochemical reforming, ethylene glycol (EG) is advantageous for its large-scale production and cheap market price. Various organic acids such as glycolic acid (GCA), oxalic acid (OXA) and formic acid (FA) can be produced with simultaneous production of high purity of dihydrogen gas during ethylene glycol oxidation reaction (EGOR). In particular, EG selective oxidation targeted at the production of GCA, which has broad applications in skin care, textile industry and adhesives.

Herein, a noble catalyst material of Pt nanoparticles supported on Se-doped porous carbon (Pt/SePC) is prepared and investigated for the selective EGOR to GCA. The Pt/SePC achieved a maximum EG conversion of 94.6% and GCA selectivity of 84.4%, and maintained this high performance with a negligible degradation during durability tests. The effect of Se doping was investigated through the experimental analyses and theoretical DFT calculations, that lattice deformation and defects introduction caused by Se led to electronic localization in Pt nanoparticle, thus the adsorption energy of intermediate reactants on Pt surface were modified. Furthermore, EGOR required low overpotential compared with oxygen evolution reaction, thus coupling EGOR and hydrogen evolution reaction required potential of 0.60 V while 1.58 V is necessary for water electrolysis. Our study could highlight favorable strategy of catalyst design with heteroatom doping for catalyst stabilization and promoting ethylene glycol conversion to value-added glycolic acid.
Effect of Salt Bridge Formation on Proton Transport in CNTs
Authors: Nakamura Akihiro , Mabuchi Takuya
Published: December 2024

Various sectors have initiated technology development projects aimed at realizing a hydrogen-based society with low carbon dioxide (CO2) emissions. A proton (H+) transfer system with high permeability and selectivity is essential for the hydrogen infrastructure and fuel cells that support a hydrogen-based society. Therefore, intensive research is underway to design bioinspired artificial proton channels. Natural proteins achieve high proton selectivity by organizing proton-conducting pathways with scattered ionizable side chains and controlling proton transport through Vehicle and Grotthuss mechanisms. The Hv1 channel is a proton-selective protein that contains the amino acids aspartic acid (Asp) and arginine (Arg) in its pathway. As shown in Figure 1, the proton transport mechanism of Hv1 channels is suggested that Asp and Arg can be protonated, allowing them to transport protons via the Grotthuss mechanism. Additionally, Asp and Arg form salt bridges to close the pathway, thereby inhibiting the transport of other ions via the vehicle mechanism. However, the relationship between Asp and Arg and their impact on the transport mechanism remains unclear. It is important to elucidate the relationship between the inhibition of transport and pore size, as well as to understand the correlation between the inhibition of transport and salt bridges, to install proton transport mechanism of Hv1 channels into artificial proton channels. In this study, carbon nanotubes (CNTs) were used as a model pore for artificial ion channels, and we analyzed the effects different sizes of CNTs modifying with Asp and Arg on ion transport properties using molecular dynamics simulations.

We adopted the armchair CNTs model shown in Table 1, using the CNTs chirality (5,5), which is known to spontaneously fill with water at room temperature, as the smallest model. For the molecular models of Asp and Arg, side chain models of Asp(N)–Arg(N) and Asp(-)– Arg(+) pairs, which can form salt bridges, were modified inside CNTs.

The results of the probability of hydrogen bond formation are shown in Figure 2. The results confirm that hydrogen bonds are always maintained at a pore radius R = 4.75 Å (CNTs chirality = 7,7) for both conditions. As the distance between Asp and Arg increases with increasing pore radius R above R = 4.75 Å, it appears that the hydrogen bonds cannot be maintained. Even when the pore radius is smaller than R = 4.75 Å, the probability of hydrogen bonding formation decreases. In the poster, we will present further structural analyses, such as the orientations of Asp and Arg and their relation to the hydronium ion conformation.

[1] Dudev, T., Musset, B., Morgan, D. et al. Selectivity Mechanism of the Voltage-gated Proton Channel, HV1. Sci Rep
5, 10320 (2015).

Figure 1
Fabrication of Tubular Alumina through-Hole Membranes by Anodization of Al Wires
Authors: Yoshinaga Minori , Yanagishita Takashi
Published: December 2024

Membrane filters with uniformly sized pores have attracted considerable attention because they are useful for filtering a variety of particulates. Among them, anodic porous alumina, obtained by the anodization of Al in an electrolyte, has been studied as a membrane filter for microfiltration because it can form a nanohole array structure with regularly arranged pores of uniform size. We previously reported that a two-layer anodization method using concentrated sulfuric acid can form highly ordered alumina through-hole membranes with high throughput [1]. Using this method, it was possible to form not only flat membrane filters but also tubular membrane filters [2]. Tubular alumina membrane filters have potential applications in filter modules for space savings and efficient microfiltration. To achieve efficient filtration in filter modules consisting of tubular membrane filters, it is necessary to increase the density of the filter packed in the module, which requires the fabrication of tubular filters with small diameters. However, it is difficult to form tubular alumina membrane filters thinner than 1 cm in diameter using a previously reported method. In this report, we describe the results of a new method based on a two-layer anodization process using concentrated sulfuric acid to form tubular membrane filters with millimeter diameters.

Electropolished Al wire was anodized in 0.3 M oxalic acid at 40 V to form anodic porous alumina. The sample was then re-anodized in 12M sulfuric acid at 40V to form a highly soluble alumina layer at the bottom of the previously formed anodic porous alumina. After anodization, the sample was immersed in a mixed solution of chromic acid and phosphoric acid to selectively dissolve the alumina layer formed in concentrated sulfuric acid, thereby exposing the Al substrate at the bottom of the pores. Tubular alumina membrane filters were obtained by selectively dissolving the Al substrate through nanopores in an iodine-methanol solution.

In this study, Al wires with diameters ranging from 2 to 5 mm were used as the starting materials, and in all cases, it was possible to form tubular alumina membrane filters without cracks. SEM observations of the obtained samples showed that the tubular alumina membrane filter was uniformly sized through the holes. The tubular alumina membrane filter obtained in this study is expected to be useful in a variety of applications.

References

[1] T. Yanagisihta and H. Masuda, Electrochim. Acta, 184, 80 (2015).

[2] T. Yanagishita, A. Kato, and H. Masuda, Jpn. J. Appl. Phys., 59, 038002 (2020).
Co-Deposited Hydrogen in Electrodeposited Pd Films: Insights from High-Temperature Thermal Desorption Spectroscopy
Authors: Hashimoto Tomoya , Fukumuro Naoki , Yae Shinji
Published: December 2024

Palladium (Pd) has been extensively studied for hydrogen absorption and desorption as a fundamental metal of the metal-hydrogen systems. When hydrogen is absorbed into bulk Pd under high pressure or via electrolytic charging, interstitial hydride α and β phases are formed. On the other hand, during Pd electrodeposition, hydrogen atoms are co-deposited in the Pd films, and not only the interstitial hydrides but also vacancy-hydrogen clusters and nanovoids containing molecular hydrogen are formed in the Pd films1). In this study, we will present the findings of Pd film analysis measured using high-temperature thermal desorption spectroscopy.

An alkaline plating bath containing 0.03 M (M = mol dm-3) palladium chloride (Ⅱ), 0.50 M ammonium chloride, and 0.05 M citric acid was used for electrodeposition of the Pd films. The pH of the plating bath was adjusted to 8.3 with an aqueous ammonia solution. A stainless steel (SUS304) plate was used as a substrate from which the Pd films could be peeled off. A platinum plated titanium mesh was used as a counter electrode. The bath temperature was maintained at either 298 or 278 K. The electrodeposition was performed at a constant current density of 50 A m-2. Hydrogen desorption spectra of the Pd films were measured under ultra-high vacuum by increasing the temperature from 300 K to 1300 K and then holding at 1300 K for several hours.

In the thermal desorption spectrum of hydrogen from the Pd film electrodeposited at 298 K, hydrogen desorption corresponding to the desorption of the interstitial hydrogen and break-up of vacancy-hydrogen clusters was observed at temperatures below 900 K1). Above 1100 K, significant hydrogen desorption which may be assigned to the desorption of molecular hydrogen from the nanovoids with grain growth and Pd evaporation was observed. The total amount of desorbed hydrogen from the Pd film was x = 6.5 × 10-2 of which 84% was molecular hydrogen in the nanovoids desorbed at temperatures above 1100 K. In the thermal desorption spectrum of the Pd film electrodeposited at 278 K, a pronounced peak ascribed to the desorption of interstitial hydrogen appeared at around 380 K, and x = 0.15 of which 68% was molecular hydrogen in the nanovoids desorbed at temperatures above 1100 K. These results show that the existing states and concentrations of co-deposited hydrogen depend on the deposition conditions of the Pd films.

This work was supported by JSPS KAKENHI Grant Number JP22K04763.

1) T. Hashimoto, T. Nakamura, N. Fukumuro, S. Yae, Mater. Trans., 64, 2466 (2023). DOI: 10.2320/matertrans.MT-M2023076
The Effect of Organic Additive on Electrochemical Fabrication of Micro-Structured Electrode for Reverse Electrodialysis
Authors: Kwon Eunji , Choi In Soo
Published: December 2024

Reverse electrodialysis (RED) is a type of salinity gradient power generation technology that is a renewable energy source that converts chemical energy into electrical energy. RED uses seawater and salt differences to produce electrical energy. Intensive research is needed to develop electrodes with excellent conductivity to reduce electrode resistance and increase performance when operating reverse electrodialysis. Conventionally, the state of the art electrode is prepared by electrodepositing Pt on metal substrate, such as Ti mesh (Pt/Ti mesh) in acidic medium. However, due to the dimension of porous mesh structure, it is difficult to form an uniform Pt layer with high coverage via normal potential- or current-controlled electrodeposition. In response to this, this research proposes an additive-induced electrodeposition for the preparation of Pt/Ti mesh electrode. A trisodium citrate (TSC) is chosen to be an additive. TSC plays both as a leveler and a suppressor and therefore it helps to control the kinetics of electrochemical process. The effect of TSC and its content on the physicochemical and electrochemical property of Pt/Ti electrode is addressed. The RED single cell test is conducted with the electrodes manufactured according to the TSC content, and the performance is compared and analyzed accordingly.
High-Entropy Materials As Solid State Electrolytes for Fluoride-Ion Batteries
Authors: Chen Zhihao , Zhong Chengchao , Okazaki Ken-ichi , Shimoda Keiji , Orikasa Yuki
Published: December 2024

Compared to conventional lithium-ion batteries (LIBs), all-solid-state fluoride-ion batteries (FIBs) offer superior theoretical energy density and enhanced safety features1. The notable advantage of FIBs is their ability to facilitate multi-electron transfer reactions between metals and metal fluorides, potentially unlocking volumetric energy densities of up to 5000 Wh L−
1. Despite these promising properties, the development of FIBs is still at an early stage. A major challenge is their low ionic conductivity at room temperature compared to cation conductors. As a result, FIBs typically require operation at elevated temperatures, in excess of 140 °C, to achieve desirable performance levels.

To overcome this problem, improving the ionic conductivity of electrolytes for FIBs is critical and involves reducing the activation energy for ion migration. High entropy materials have emerged as a potential solution to this challenge, offering a novel way to effectively reduce the activation energy2. Recent advances in this field have led to the development of a lithium superionic conductor, which demonstrates the potential of high-entropy materials to revolutionise ion conductivity3.

In our study, we focused on the synthesis of a high-entropy material, (LaCeNdSmGd)F3, using a solid-state reaction method. Extensive analysis using Rietveld refinement and scanning electron microscopy (SEM) confirmed that the synthesised (LaCeNdSmGd)F3 retains the crystal structure characteristic of LaF3. Using electrochemical impedance spectroscopy, we found that (LaCeNdSmGd)F3 exhibits an ionic conductivity of 1.3×10-7 S cm−
1 at 373 K. Furthermore, Arrhenius plots revealed that (LaCeNdSmGd)F3 has a significantly lower activation energy compared to LaF3, highlighting the effectiveness of high-entropy materials in reducing activation energy.

The introduction of a wide range of cations into the high entropy material (LaCeNdSmGd)F3 leads to structural disorder and site energy overlap. This complexity within the crystal lattice effectively lowers the energy barriers associated with ion migration, thereby enhancing the ionic conductivity of the fluoride solid electrolyte.
Fluoride Ion Conduction of BiSF with Distorted PbFCl-Type Structure
Authors: Ito Yukino , Tachibana Shintaro , Kageyama Hiroshi , Orikasa Yuki , Zhong Chengchao
Published: December 2024

All-solid-state fluoride ion (F−) rechargeable batteries are expected to have a high energy density due to their wide potential window and the availability of multi-electron reactions at the electrodes. F− conductors used as solid electrolytes have lower conductivity at room temperature than cationic conductors, and the crystal structures studied are limited. We have previously discovered that an anion-ordered structure created by F− and S2− in sulfidefluoride has a F− conduction path that is not found in single anion compounds1), indicating that mixed-anion compound can be used to develop new F− conductors. In this study, we focused on BiSF, a fluorosulfide with distorted PbFCl-type structure. The 6s2 lone pair electrons (LPEs) around Bi3+ are expected to promote F−

conductivity due to their high polarizability. In addition, the ionic conductivity of BiSF was compared with LaSF that has PbFCl-type structure but without LPEs.

BiSF was obtained by mixing Bi2S3 and BiF3 in an Ar atmosphere, forming pellets, placing them in a cell for high-pressure synthesis, and performing high-pressure synthesis at 5 GPa and 650°C for 1 hour. LaSF was obtained by mixing La2S3 and LaF3 under an Ar atmosphere, pellet forming, vacuum sealing, and calcination at 800 °C for 24 hours. Powder X-ray diffraction measurements (XRD) were used to identify the experimental samples, while AC impedance methods were used to measure ionic conductivity.

The XRD results confirmed that the synthesized sample contained few impurities and the target material BiSF was synthesized. AC impedance measurements of BiSF showed a rising behavior at the low frequency side, indicating that BiSF has ionic conduction. The ionic conductivity of BiSF at 30°C was 4.22 × 10−6 S cm−1. LaSF, which has similar PbFCl-type crystal structure as BiSF but without LPEs, did not exhibit F− conduction, suggesting that the F− conduction in BiSF is affected by LPEs present in Bi3+.

【References】

1) S. Tachibana, C. Zhong, K. Ide, H. Yamasaki, T. Tojigamori, H. Miki, T. Saito, T. Kamiyama, K. Shimoda,

Y. Orikasa, Chem. Mater., 35, 4235-4242 (2023).
Fluoride Ion Conductor of Fluorosulfide with Double-Layer Honeycomb Structure
Authors: Oura Honoka , Tachibana Shintaro , Hirai Shinziro , Orikasa Yuki , Zhong Chengchao
Published: December 2024

All-solid-state fluoride ion batteries (FIBs) have attracted considerable attention due to their high theoretical energy density and high safety compared with those of conventional lithium-ion batteries (LIBs) [1]. However, the practical application of FIB lacks suitable solid electrolyte with high ionic conductivity and wide electrochemical potential window at room temperature. In addition, most of the fluoride ionic conductors reported previously are limited to fluorides such as fluorite, tysonite-type, and perovskite-type structures [2]. Therefore, increasing the variations of crystal structures for fluoride ion conductors are expected.

Fluorosulfides containing S2− and F− with largely different ionic radii are ideal for creating anion-ordered structures and expected to create fluoride ion conductors not found in reported fluoride[3]. In this study, we synthesized rare-earth fluorosulfides LaM
2F3S2 (M = Ba, Sr) and measured their ionic conductivity. Powder samples were weighed in stoichiometric ratio under an Ar atmosphere and pulverized by mortar mixing. The pelleted sample was placed in a Ta container, vacuum sealed using a quartz tube, and then calcined. The obtained samples were structurally evaluated by XRD measurement. For the evaluation of conductivity by the AC impedance method, the obtained powder was formed by isostatic pressing, sintered again, and Au electrodes were deposited on both sides as sintered specimens.

In the crystal structure of these fluorosulfides, anion-ordered 2D crystal structures are formed, which cannot be achieved in a single anion compound. The F− conducting layer is a double-layer honeycomb structure, with F− conducting two-dimensionally via four-, six- and four-coordination sites. The conductivity at 100°C is in a order of 10-6 S cm-1, which is highest among mixed-anion compounds but is several orders of magnitude lower than previously reported single-anion compound. On the other hand, the activation energy was 0.50 eV, which is comparable to that of the fluorite-type structure Ba0.6La0.4F2.4. The material development of fluoride ion conductors using flurosulfide compounds is expected to increase crystal structure variations with fluoride-ion conduction pathways.

References:

A. Reddy, M. Fichtner, J. Mater. Chem, 21, 17059-17062(2011).

Motohashi, T. Nakamura, Y. Kimura, Y. Uchimoto, K. Amezawa, Solid State Ionics., 338, 113-120(2019).

Tachibana, C. Zhong, K. Ide, H. Yamasaki, T. Tojigamori, H. Miki, T. Kamiyama, K. Shimoda, Y. Orikasa, Chemistry of Materials
., 35, 4235-4242(2023)