bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulative Analysis of Crucial Effective Transport Parameters of Li-Ion Cells Based on Experimental Voltage and Impedance Behavior
Authors: Mühlpfort Raphael , Pfeifer Leonie , Heß Anne , Wetzel Thomas , Seegert Philipp 
Published: December 2024

The performance and aging behavior of a lithium-ion battery (LIB) are strongly influenced by inner processes as well as outer influence factors like the thermal boundary conditions.
A valuable and established tool to describe and gain a better understanding of the cell behavior is modelling using equivalent circuit models (ECM). For a deeper understanding and more detailed insights into the processes taking place inside the cell, physically based models, resolving the complex interaction of charge, heat and mass transfer as well as the electrochemical reaction by physical equations are needed. In this work, a model consisting of the combination of an equivalent circuit and a physical pseudo-2D (p2D) model according to Doyle-Fuller-Newman (DFN) was developed and implemented in COMSOL Multiphysics.
With the help of this model, impedance spectra and voltage behavior based on the multi-physical processes can be predicted and the underlaying parameters systematically analyzed. By comparison of the simulated cell behavior with experimental data, the physical parameters determining the overall cell behavior can be identified. This inverse-parameterization approach can be accelerated significantly by adding a least square gradient-based optimization tool, fitting the simulated behavior to an experimental data set by automatically optimizing the values of the physical parameters.
A challenging task by applying a DFN modeling approach combining with an optimization algorithm is to identify the value ranges of the crucial effective parameters, which are influenced by the microstructure of an electrode. An optimization of such a variety of parameters which interact strongly with each other may lead to a convenient fitting result but with underlying physical parameters which aren’t plausible. To take care of this issue this work focuses on both, voltage and impedance behavior of the cell as well on the investigation of the interaction of crucial parameters and their influence in the time and frequency domain. In addition, a 3D-microstructure model is used to narrow down the range of the effective transport parameters and to enhance the classical DFN and to complement in a target-oriented way.
(General Student Poster Award Winner, 1st Place) Synthesis and F-Ion Conduction of Ba0.57M0.43F2.43 (M = Y, La, Nd, Sm, Bi) As Solid Electrolytes for All-Solid-State F-Ion Batteries
Authors: Pattanathummasid Chanachai , Tani Kazuki , Matsunaga Toshiyuki , Takami Tsuyoshi 
Published: December 2024

All-solid-state fluoride-ion batteries (FIBs) have attracted research attention because these batteries possess a high energy density surpassing the state-of-the-art Li-ion batteries.1 Yet, the lack of a fluoride-ion conductor with both highly ionic conductive and highly stable is one of the key bottlenecks in the development of FIBs. Conventionally, La0.9Ba0.1F2.9 (LBF) is used as a solid electrolyte in FIB. However, the cathodic stability of LBF limits the choice of anode materials unable to be below the reduction potential of LaF3/La as plating occurs. Our previous study showed that Ba4Bi3F17 (R−3) with a fluorite-like sublattice could form the disordered phase equivalent to a fluorite Ba0.57Bi0.43F2.43 (Fm−3m), enabling a fast fluoride-ion conduction comparable to LBF.2 By replacing Bi with the elements that have lower equilibrium fluorine activity, the electrolyte materials with higher stability could be anticipated. Therefore, in this study, mechanochemical synthesis was used to fabricate the disordered phases of Ba0.57M0.43F2.43 (M = Y, La, Nd, Sm, Bi) to study their electrochemical stability and F-ion conductivity.
The materials were synthesized using a mechanochemical technique with a planetary ball mill at 600 rpm for 12 h under a static argon atmosphere. The resultant phases were characterized using synchrotron X-ray diffraction (XRD) and time-of-flight neutron powder diffraction (NPD) to study the fluorine position and distribution in the structure. Impedance measurements were performed using blocking electrodes to estimate the electrical conductivity of the materials, and the electronic insulation of the materials was confirmed by DC polarization. Cyclic voltammetry was used to estimate the electrochemical stability window of the materials in comparison with LBF using Pt and Pb as a working electrode and a counter electrode, respectively.
Mechanochemical synthesis of the mixture of BaF2 and MF3 was shown to preserve the fluorite structure (Fm−3m) regarding the diffraction patterns. Electrochemical impedance spectroscopy showed the Nyquist plot of these materials as a semi-circle with a spike feature at low frequencies which is a typical response of ionic conduction under the blocking electrode scheme. The Arrhenius plot of the materials exhibited a slight difference in conductivity where the order of conductivity could be ranged from M = Bi > La > Nd > Sm > Y. The electrochemical stability window of the materials measured by cyclic voltammetry revealed that the stability of materials is in the order M = Y > Sm > LBF > Nd > La > Bi. The extraordinarily wide windows of M = Y and Sm exceeding that of LBF without a reduction peak open the possibility towards the use of high-energy anode materials, which will increase the energy density of the battery.
Dry-Processed Silicon-Graphite Composite Electrodes for Lithium-Ion Battery
Authors: Sheem JunMyoung , Kim Young-Jun 
Published: December 2024

As the demand for increased energy density grows in the contemporary electric vehicle (EV) sector, lithium-ion batteries (LIBs) have emerged as the preferred choice within modern secondary battery technologies [1]. These batteries, owing to their remarkable characteristics, are valued for their outstanding energy density, enhanced specific energy efficiency, and high-performance metrics compared to alternative battery technologies [2]. With noticeable constraints becoming evident, endeavors are currently underway to discover effective solutions for commercial LIBs. These efforts primarily focus on advancing both cathode and anode electrodes to achieve high-energy density approaches. To attain this high energy density, the use of a dry-process technique is necessary. Dry processing offers several advantages over traditional solvent processes, particularly in terms of operational cost and energy efficiency, making it a promising alternative for electrode manufacturing in LIBs. Moreover, the absence of solvents allows to produce electrodes with higher mass loadings, potentially facilitating battery miniaturization. In this study, electrodes employing a solvent-free dry-process method were fabricated utilizing a blend of silicon and graphite as the anode material. Each step was meticulously optimized, particularly in the utilization of Polytetrafluoroethylene (PTFE) material, which is not typically used in electrode materials, resulting in significant advancements in alleviating potential issues. Building upon this, high-loading, high-density electrodes were successfully produced using the dry-process method. In this research, a current density of 6 mA/cm2 and an electrode density of 1.6 g/cc were successfully achieved using a dry process method. The manufactured electrode utilizes 20% silicon content to address the limitations of silicon oxide, achieving performance equal to or exceeding that of slurry state electrodes. These dry-process electrodes show potential to facilitate the development of lithium-ion batteries under harsh cell design conditions in the future.

Reference
s

[1] Nano Energy, 2017. 31: p. 113-143.
[2] Nature Chem
7, 19–29 (2015).
Fibrous Porous Composite Interlayer Derived from Soft Dendritic Colloids for Lithium-Sulfur Batteries
Authors: Truong Tuyen T.T , Petrecca Michael J. , Leatherman Jaden R. , Velev Orlin D. , Fedkiw Peter S. 
Published: December 2024

Lithium-sulfur (Li-S) batteries have emerged as a highly promising energy storage technology, owing to their high theoretical energy density and being based on abundant resources. However, they are challenged by the undesirable diffusion of soluble lithium polysulfides (LiPSs) towards the lithium metal anode in electrolytes during discharge/charge cycles, which is commonly known as the shuttle behavior of LiPSs. This phenomenon ultimately leads to the degradation of the long-term Li-S batteries stability and severely limits their practical applications. To overcome this challenge, we propose the development of an innovative composite intermediate interlayer (MWCNT/SDC-PVDF) aimed at reducing charge transfer resistance and effectively capturing dissolved polysulfides.
The novel polymer composite is synthesized using a recently introduced method to produce soft dendritic colloids (SDCs). The SDCs are generated through turbulent solvent-nonsolvent induced phase separation to precisely regulate the size and morphology of precipitated PVDF across varying length scales. The integration of multiple wall carbon nanotubes (MWCNT) and SDC-PVDF within a high-shear mixer enables the formation of a homogeneous composite mixture. The resulting matrix interlayer situated between the carbon nanotubes and the SDC-PVDF fibrillar polymer network exhibits a fibrous porous structure characterized by a substantial surface area higher than 103.04 m2g-1, effectively facilitating the entrapment and anchoring of LiPSs within this matrix. Furthermore, the porous framework also allows for re-utilising LiPSs in subsequent cycles to improve the irreversible of the Li-S cell.
The flexible fibrous and porous MWCNT/SDC-PVDF interlayer, featuring a thin layer (∼ 55 μm ) and high conductivity, serves to mitigate cell polarization. A Li-S cell with the interlayer demonstrates a notable initial reversible capacity of 1,100 mAh g-1 at 0.2 C. The cell also achieved good capacity retention of 65% after 300 cycles at 0.2 C and 81% retention at 0.1 C after 150 cycles.

Figure 1
Multimodal Analysis of Corrosion for AA6016 Alloy at the Boundaries between Aluminum Matrix/Intermetallic Particles
Authors: Hiraoka Yuki , Murase Yoshiharu , Katayama Hideki , Tsutsumi Yusuke , Kadowaki Mariko , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki 
Published: December 2024

Aluminum alloys are attracting attention as lightweight materials for automobiles, and the fact that intermetallic particles indispensable for improving strength of the alloys can be harmful to the corrosion resistance has become an issue. However, the initial corrosion behavior at the interface of intermetallic particles for aluminum alloys has been hardly examined using a comprehensive analysis method. In this study, a nano-micro scale multimodal analysis of Energy Dispersive X-ray Analysis (EDS), Electron Backscatter Diffraction (EBSD), and Kelvin Force Microscopy (KFM) was performed to clarify the initial corrosion behavior for AA6016.
AA6016 specimens (20 × 20 × 1 mm) were subjected to SEM-EDS/EBSD measurements after mirror polishing, followed by continuous KFM measurements after ion milling. The specimens were then immersed in 100 mL of 0.5 wt% NaCl solution for 1 hour at a corrosion test. The surfaces of the specimens were cleaned with distilled water, dried and subjected to subsequent KFM measurements. The measurement of SEM-EDS was conducted again after the series of KFM measurements prior and post corrosion test.
Fig. 1 shows SEM images of the typical specimen surface for AA6016 before corrosion tests. As shown in Fig. 1, two types of intermetallic particles: Al-Fe-Si and Mg-Si were identified by EDS measurements. The KFM measurements of the potential distribution on specimen surfaces confirmed that both intermetallic particles were noble in potential relative to the aluminum matrix. However, less significant difference in the potential was detected at the grain boundaries identified by the EBSD measurements. After the corrosion test, some trenches were formed at the boundaries of the Al-Fe-Si type particle, and the noble potential area expanded around the particle. As for the Mg-Si type particles, a dissolution of Mg was detected at the particle, and the noble potential region disappeared at the particles immediately after the corrosion test but reappeared with time. Furthermore, the formation of thick oxide films was implied after the corrosion test, especially at the boundaries of Al-Fe-Si type particle as well as at the Mg-Si type particle.
Thus, the initial corrosion behaviors of AA6016 related to the compositional/electrochemical modifications at and around intermetallic particles were demonstrated by using the nano-micro scale multimodal (EDS-EBSD-KFM) analysis. Although the modifications of compositions (Mg and O) as well as noble potential distribution were restricted within the particle for Mg-Si type particle, they were expanded at the boundaries and around the particle for Al-Fe-Si type particle. The Al-Fe-Si type intermetallic particles would play more important role than those of Mg-Si type particles in promoting localized corrosion for AA6016.

Figure 1
Evaluation of the Applicability of Rotating Cylindrical Anodes for Higher Speed Copper Electrolytic Refining
Authors: Kaizuka Gen , Miyamoto Masayuki , Fukami Kazuhiro , Murase Kuniaki 
Published: December 2024

With the aim of increasing the overall speed of conventional copper smelting, in which a dry process and an aqueous electrolysis are connected in series, the challenge is to increase the speed of the electrolysis by increasing the current density, since the electrolysis is the rate-determining step in the series. However, electrolysis at high current density causes passivation of the anode due to a significant increase in the copper ion concentration near the anode, which inhibits electrolysis.
The use of forced convection (stirring or jetting) has been considered to suppress passivation. However, it is not easy to apply the effect of forced convection uniformly across the electrode surface in the conventional electrolysis method, in which plate electrodes are arranged in a dense array.
In this study, we proposed a method to obtain forced convection by rotating the cylindrical electrode (anode) as shown in the figure. The diffusion of copper ions from the anode surface can be promoted efficiently and uniformly by using this method. As a first step in the evaluation of the applicability, we performed numerical simulations of the tertiary current distribution to investigated the effects of the cylindrical anode rotation on the correspondence between the current density and the copper ion concentration near the anode.

Figure 1
Effect of Carbon Additives on the Performance of Oxide-Based Cathode for PEFC
Authors: Yusuke Bokkai , Yamamoto Kanta , Takeuchi Yuu , Monden Ryuji , Ishihara Akimitsu , Fukunaga Hiroshi 
Published: December 2024

To further advance the adoption of PEFCs, there's a growing need for developing non-Pt catalysts. Among these, oxide catalysts have caught much attention due to their impressive resistance to corrosion in acidic conditions. However, the lack of electronic conductivity is a challenge, and it is considered that new design guidelines for catalyst layers different from existing Pt/C electrodes are needed. In the field of secondary batteries, it has been reported that the shape and amount of carbon materials used as conductive additives affect performance in electrodes using materials with poor conductivity. Based on these reports, the effects of adding carbon to the catalyst layer for PEFC electrode using oxide catalyst were investigated.
Using an oxide catalyst with Zr as the active site[1, 2], we examined the effects of adding carbon of different shapes to oxide catalysts on electrode structure and power generation performance. The catalyst layer was prepared using a drop method. The IV performance was improved with the addition of carbon, and the catalyst layer with KB added showed higher current density at all potentials than CNT. Thus, it was revealed that the shape of conductive additives also affects the performance of electrodes in PEFCs. When the amount of catalyst layer coating was changed, IV performance improved by increasing the coating amount of the catalyst. From SEM images of cross-sections, it was found that catalyst layers with a higher coating amount had larger aggregates of catalyst particles, larger voids in the catalyst layer, and thicker membranes.
To control the structure of the electrode, a spray coating method was used for the preparation of the catalyst layers. The catalyst layers were fabricated by varying the gun distance, discharge amount, and heater temperature during spray application. IV performance was highest under conditions with a large gun distance. From structural observations, it was found that with a large gun distance, the aggregates became smaller.
To investigate the impact of spray coating conditions on catalyst layer structure, titania was used as the catalyst, and layers were produced by varying the discharge amount and heater temperature. Structures with smaller agglomerates were observed when the discharge amount was low. Similarly, smaller agglomerates were observed when the substrate temperature was higher. These results suggest that porous structures with suppressed particle agglomeration are more likely to form under conditions conducive to drying.
References
[1] A.Ishihara et al., J. Phys. Chem. C, 123, 18150 (2019).
[2] Y.Takeuchi et al., Chem. Lett., 51, 927 (2022).
Promoted Electrochemical Performance of Direct Methanol Fuel Cell By Using PtRu Deposited and TiO2 Coated Porous Carbon Nanofibers
Authors: Gao He , Ishitobi Hirokazu , Nakagawa Nobuyoshi 
Published: December 2024

Direct methanol fuel cell (DMFC) has drawn much attention as a promising power source due to its high energy density and environmental friendliness characteristic. But the slow kinetics of methanol oxidation reaction (MOR) limit its wild applications. A higher MOR activity electrochemical catalyst with low PtRu loading amount is now desired to act as anode catalyst layer of DMFC.
In our previous studies, PtRu deposited and TiO2 coated carbon nanofibers (PtRu/TCCNFs) prepared by using electrospinning technology shows a better performance than PtRu/C commercial catalyst. In direct methanol fuel cell (DMFC) applications, this fiber-structure catalyst with a diameter of around 500 nm can offer more gaps by overlapping themselves in catalysts layer, which is benefit for mass transfer of methanol oxidation reaction. However, the CL is thicker than other catalysts based on carbon black. To overcome this feature, another CNFs with porous structure (P-CNFs) was prepared by using electrospinning technology with a mixture precursor solution consist of polyacrylonitrile (PAN), polystyrene (PS) and dimethylformamide (DMF). The P-CNFs with meso- and micropores can not only offer more active sites by inner space to deposit PtRu particles but also decrease the thickness of the catalyst layer.
In this study, different PS to PAN ratio and electrospinning condition was investigated to confirm the most suitable fiber diameter, surface area and pore size by using BET and SEM. Subsequently, different PtRu loading and TiO2 coated catalysts were prepared and measured by EDX and XRD to confirm the elements content and PtRu crystal size. After that, electrochemical surface area (ECSA) and MOR mass activity was tested by three-electrode cell to obtain the catalysts performance. Finally, the porous and non-porous catalysts were used for DMFC application with the catalyst loading of 1.0 mg-PtRu/cm2, the maximum current and power density was measured to compare the performance with commercial catalyst.
The results show that the condition of 18 kV and 15 cm for electrospinning with the PS to PAN ratio of 1.00 exhibit the most suitable pore size (≥10 nm), and BET surface area is 249 m2/g. The prepared PtRu/TCCNFs and PtRu/P-TCCNFs show nearly the same PtRu loading and atomic ratio, as well as Ti content, and with the PtRu crystal size of 3.3 nm. The MOR mass activity shows a rank of PtRu/P-TCCNFs> PtRu/TCCNFs > PtRu/C. The figure shows DMFC performance of PtRu/C, PtRu/P-TCCNFs, and PtRu/TCCNFs catalysts. The result exhibits that the porous structure catalyst has the highest maximum current and power density, and PtRu/TCCNFs is also higher than that of PtRu/C commercial catalyst.
The improved DMFC performance of PtRu/P-TCCNFs is attributed to the accelerated mass transportation due to the porous structure, which offers channels to allow reactants and products passing through the layer.

Figure 1
Effect of Pore-Forming Agent on Concentration Overpotential of Carbon-free Pt Electrodes for PEFC
Authors: Segawa Haruki , Sasaki Takaaki , Shimada Iori , Osada Mitsumasa , Takahashi Nobuhide , Fukunaga Hiroshi 
Published: December 2024

Platinum is widely recognized for its high reactivity and is commonly used in the cathodes of polymer electrolyte fuel cells (PEFCs). However, due to its high cost and limited availability, there is a pressing need to reduce the amount of platinum used. Conventional low-platinum electrodes, comprised of Pt-supported carbon (Pt/C) and ionomer, face challenges such as catalyst dissolution and redeposition, carbon support corrosion, and platinum poisoning by the ionomer. This study focuses on Pt nanosheets (Pt(ns)) [1] as a novel catalyst with high activity and durability. These electrodes are considered to be a novel low-platinum electrode with high durability. In our previous research electrodes fabricated using Pt(ns) observed significant overvoltage in high-current density regions, attributed to hindered gas diffusion caused by catalyst stacking. Therefore, we aimed to reduce overvoltage by increasing the porosity of the electrode through the addition of a pore-forming agent. Inspired by reports on utilizing urea (Ur) to enhance electrode porosity [2], electrodes were prepared by incorporating Ur into the ink, followed by dissolution and removal to create voids. The resulting cathode catalyst layer was then hot-pressed to assemble the membrane-electrode assembly (MEA). I-V measurements demonstrated that the addition of Ur suppressed concentration overvoltage. Scanning electron microscopy (SEM) observations revealed increased electrode porosity compared to non-additive electrodes. Furthermore, despite a similar electrochemical surface area (ECSA) compared to non-additive electrodes, the mass activity (MA) in the low-current density region significantly improved.
Acknowledgement
Part of this paper is based on results obtained from a project, JPNP20003, subsidized by the New Energy and Industrial Technology Development Organization (NEDO).
References
[1] S. Takenaka et al.,
J. Phys. Chem.,
119, 12445(2015)
[2] T. Suter et al., Nanomaterials.,
11, 2530(2021)