bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploration of Low-Temperature Formation Pathways for Garnet-Type Lithium-Ion Conductors
Authors: Onoue Kana , Nasu Akira , Kobayashi Hiroaki , Matsui Masaki 
Published: December 2024

[Purpose]
High-temperature sintering is necessary to obtain good contact between the cathode active material and the solid electrolyte in the development of all solid-state batteries. However, high temperature sintering causes the formation of a high resistivity layer, thus reduction of the sintering temperature is desirable. In this study, we investigated a low-temperature synthesis method in garnet-type lithium-ion conductors to synthesize fine particles without crystal growth that exhibit high sinterability at low temperatures. We explored a new reaction pathway to obtain garnet-type lithium-ion conductors at low temperatures by promoting spontaneous reactions between transition metal oxides at low temperatures through the refinement and amorphization of the raw materials.
[Experimental]
Li6.5La3Zr1.5Nb0.5O12(LLZNO) was synthesized by solid phase method using LiOH.H2O, ZrO2.La(OH)3, and amorphous Nb2O5 as precursors. The precursors were synthesized as follows: 1) nano-ZrO2 was synthesized by hydrolysis and coprecipitated with La(OH)3 to form a composite; 2) amorphous Nb2O5 was synthesized by DMF reduction.1

These starting materials were wet ball-milled, then pelletized and sintered at a predetermined temperature for 12 hours under an Ar atmosphere. The products were identified by powder X-ray diffraction. Changes in the local structure and electronic state of the transition metals at different sintering temperatures were analyzed by XAFS measurements.
[Results & Discussions]
Formation of an amorphous intermediate with high reaction activity was observed at 300 ºC by using Amorphous Nb2O5 to enhance the reaction activity of the starting material. The XAFS results show this amorphous intermediate has a disordered structure with a similar coordination environment around Nb to the La3NbO7 crystal phase. The ZrO2 synthesized by hydrolysis is a low-crystalline nanoparticle, and the coordination environment of Zr changes at 100 ºC lower than that of the commercial raw material. The formation of the target cubic LLZNO was confirmed at 400 ºC. The LLZNO crystalline phase formed from this amorphous intermediate is fine and could reduce grain boundary resistance in the preparation of sintered bodies. Finally, a single phase of LLZNO was obtained at 700 ºC, about 300 °C lower than the conventional solid phase method2. In summary, the results show that the destabilization of starting materials are effective for enhancing the reaction of transition metal oxides at low temperatures. These results suggest that controlling the phase stability of starting materials is an important parameter for the design of low-temperature synthesis of cubic LLZNO.
[References]
1: H. Iguichi et al., ACS Appl. Nano Mater., 5, 7658-7663, 2022
2: N. C. Rosero-Navorro et. al, Solid state Ionics, 285, 2016, (6-12)
Prediction of Li Ion Conductivity Using a Denoising Autoencoder and an Attention for Experimental Data
Authors: Yokoyama Yumika , Tanihata Naoto , Takeda Hayami , Nakayama Masanobu 
Published: December 2024

While all-solid-state batteries composed of inorganic materials are attractive in terms of safety, rate performance is still insufficient. One of the causes is rather poor ionic conductivity of the solid electrolytes, and new high ionic conductive materials are required. Li containing NASICON-type materials are one of candidates due to its high Li ion conductivity. Many efforts have been devoted to improve their Li ion conductivities by changing composition and/or sintering conditions. Meantime, many experimental data, such as optical spectroscopy, diffraction, and so forth, are accompanied in the process of measurements for ionic conductivities. Making a link between ionic conductivity and all the analytical outputs may lead to good guideline for designing materials, though interpretation of analytical output is often difficult.
In this study, we focused on Li1.45Ca0.15Zr1.85Si015P2.85O12 ( LCZSP ) [2] doped with Ca and Si in LiZr2(PO4)3, which belongs to NASICON-type solid electrolyte that exhibits high lithium-ion conductivity and stability against metallic lithium[1]. We reported that the conductivities of this material change depending on the sintering conditions, where we performed 54 synthesis, XRD and Li ion conductivity measurements.[3] Revisiting these experimental data, we tried to make link between XRD and conductivities through machine learning.
Fig. 1 is the schematic representation of the present machine learning model based on deep neural network techniques. An XRD pattern contains noise derived from device, human factors, and so forth. To reduce the influence of noise in the XRD measurement data, a denoising autoencoder was utilized in the model. In addition, XRD patterns are reduced to a two-dimensional representation by the denoising autoencoder and make a link from encoded variables to the ionic conductivities( The blue and yellow areas in Fig. 1 ). The use of the denoising autoencoder enables the construction of a more general model for experimental data. Furthermore, we aimed to enhance the prediction accuracy and interpretability by introducing an attention mechanism that learns the points of interest in the spectrum ( The yellow-green area in Fig. 1 ).
Here, we successfully fit the ionic conductivity through autoencoder derived variables, and confirm an improvement of fitting results by implementation of the attention mechanism. The details will be presented in our poster session.

References

[1] Y. Li, et al.
Proc. Natl. Acad. Sci. U. S. A., 113,13313–13317 (2016)
[2] F. Hiroko, et al., RSC Advanced, 12, 30696-30703 (2022)
[3] H. Takeda, et al., Mater.
Adv., 3, 8141-8148 (2022)

Figure 1
Titanium Compound Coating on SUS Separator for PEFC By Screen Printing
Authors: Yabe Moeka , Watanabe Hikari , Shitanda Isao , Itagaki Masayuki , Kogure Tomonari , Tanino Hitoshi 
Published: December 2024

Currently, the metal separators of polymer electrolyte fuel cells (PEFCs) are mainly made of Ti alloys with press working. According to the report by Strategic Analysis Inc1), Ti separator accounts for a large ratio of the PEFC stack cost. To reduce this cost, it is effective to use inexpensive stainless steel and to apply the coating by screen printing, which is relatively easy to form patterns and less expensive than evaporation or sputtering. However, stainless steel has lower corrosion resistance than that of titanium, and its conductivity decreases in aqueous solution due to the formation of passive film. The purposes of this study are to develop a coating with excellent corrosion resistance and conductivity, as well as adhesion and durability, and to apply the coating on stainless steel by screen-printing. Titanium nitride and titanium carbide were employed as tillers among titanium compounds that have high corrosion resistance and sufficiently low electrical resistivity comparable to that of titanium. As a result of the research, a coating thickness of several hundred micro-m became possible, and it was decided that the gas flow path fabrication would also be done by screen printing.
In this experiment, we used titanium nitride powder with different particle sizes, Olycox KC-1300 as binder, and 2-(2-butoxyethoxy) ethyl acetate as solvent to prepare printing pastes. 4 g of binder and 10 mL of solvent were weighed and stirred at 80°C for 12 hours using a magnetic stirrer. 4 g of the stirred solution was mixed with 4 g of titanium nitride powder to form a paste. The paste was screen-printed on SUS304 using a plate simulating a gas flow channel, and then dried at 250°C for 6 hours. The resistance of the coatings prepared by the above method was evaluated after pressure treatment. In addition, anodic polarization was measured in a three-electrode system. The contact resistance was targeted to be less than 10 mΩcm2 , the target value for the contact resistance of PEFC separators, as specified by the U.S. DOE.2)

References

1) Mass Production Cost Estimation of Direct H2 PEM Fuel Cell Systems for Transportation Applications: 2017 Update, Brian D. James, Jennie M. Huya-Kouadio, Cassidy Houchins, Daniel A. DeSantis, Strategic Analysis Inc., December 2017.
2) Fuel Cell Technologies Multi-Year Research, Development, and Demonstration Plan, U.S. DOE, 2017
Selective Electrochemical Nitrate Reduction to Ammonia on Co-Based Catalysts
Authors: Quinones-Gomez Laura , Dinh Cao Thang 
Published: December 2024

About 150 million metric tons of ammonia (NH3) were produced in 2023 mainly for agricultural purposes as a fertilizer [1]. This compound is industrially produced by the conventional Haber-Bosch process under high temperatures (350 – 550 °C) and high pressure (150 – 350 atm), thus, its production accounts for 1.8 tons of CO2 emissions per ton and 2% of the energy consumed in the world [2]. These factors have led to an interest in developing green alternative methods that allow the production of large amounts of NH3. Therefore, it has been demonstrated that the electrocatalytic synthesis of NH3 is a viable route that can be developed via the reduction of nitrate (NO3
-) to simultaneously mitigate its pollution in water sources, which has become a major human health concern when it is consumed [3]. Since the electrochemical reduction of NO3
- involves a complex eight – electron process, it is vital to design a highly selective, active, and stable catalyst. In this work, the performance of Co-based catalysts in alkaline conditions was evaluated and our studies demonstrated that a three-dimensional (3D) Co substrate can achieve a faradaic efficiency (F.E.) of up to 86% at +0.023 V vs RHE (Reversible Hydrogen Electrode) with a partial current density of 23 mA cm-2. However, in the presence of an excess of NH3, Co corrosion is promoted while creating a Co-NH3 complex. In order to avoid this, the thermo-oxidation of Co foam at 400, 600, and 800 °C was performed, proving that a larger oxide layer improves the stability as well as increases the active surface area of the electrode. Furthermore, the samples could reach greater current densities when subjected to a pre-reduction treatment. The sample oxidized at 600 °C presented superior performance, achieving a F.E. of 66% at +0.023V vs RHE, a partial current density of 170 mA cm-2, and approximately 8 h of stability. This work has provided an opportunity to explore the influence of the oxide layer on NH3 synthesis, as well as the necessity of advancing novel strategies to enhance the selectivity and stability of the proposed catalyst.
[1] Production of ammonia worldwide from 2010 to 2023. Statista (2024). Retrieved from: https://www.statista.com/statistics/1266378/global-ammonia-production/#:~:text=Ammonia%20production%20has%20remained%20fairly,approximately%2064.6%20million%20metric%20tons.
[2] Wang, J., Cai, C., Wang, Y., Yang, X., Wu, D., Zhu, Y., Li, M., Gu, M., & Shao, M. (2021). Electrocatalytic Reduction of Nitrate to Ammonia on Low-Cost Ultrathin CoOx Nanosheets. ACS Catalysis, 11(24), 15135–15140. https://doi.org/10.1021/acscatal.1c03918
[3] Xu, H., Ma, Y., Chen, J., Zhang, W., & Yang, J. (2022). Electrocatalytic reduction of nitrate: a step towards a sustainable nitrogen cycle. Chemical Society Reviews, Issue 7. https://pubs.rsc.org/en/content/articlelanding/2022/cs/d1cs00857a
Fabrication of Nanopillar Arrays with Wettability Gradients by Nanoimprinting Using Anodic Porous Alumina Molds
Authors: Uchimura Misaki , Kitahara Runa , Yanagishita Takashi 
Published: December 2024

When water droplets form on a surface with a continuously changing wettability, they spontaneously move from a higher to a lower water droplet contact angle. Such wettability gradient surfaces are expected to have a variety of applications, including analytical chips that do not require pumps. We previously reported that the formation of a wettability gradient surface is possible by continuously varying the pore size of anodic porous alumina obtained by the anodization of an Al substrate [1,2]. In this report, we describe the formation of nanopillar arrays with a wettability gradient by nanoimprinting using anodic porous alumina with continuously varying pore sizes. The results of the evaluation of the transport distance of water droplets formed on the surface of the resulting nanopillar arrays are also shown. This method makes it possible to impart wettability gradient properties to various substrate surfaces.
Ideally ordered anodic porous alumina with an interpore distance of 1 μm was obtained by the anodization of an Al substrate. The resulting anodic porous alumina was immersed in phosphoric acid solution at a constant speed to produce a hole array structure with continuously varying pore sizes. Polymer nanopillar arrays with continuously varying diameters were obtained on glass substrates by nanoimprinting using the resulting anodic porous alumina as a mold. The surfaces of the resulting polymer pillar arrays were hydrophobically treated, and the contact angles of the water droplets were measured. Water droplets were formed on the surface of the polymer pillar array, and the spontaneous transport distance of water droplets was measured.
SEM observations showed that polymer pillar arrays with continuously changing diameters were formed via nanoimprinting. From the contact angle measurements, it was confirmed that the contact angle changed continuously as the diameter of the nanopillars changed. When water droplets formed on the surface of the nanopillar arrays, spontaneous movement of the droplets was observed. This method is effective as a surface treatment for the spontaneous transport of water droplets on various substrate surfaces.
References
[1] T. Yanagishita and Y. Boushi, Langmuir, 39, 862 (2023).
[2] Y. Boushi and T. Yanagishita, Langmuir, 40, 5455 (2024).
Enhanced SnO2 FETs via Selective Area Fluorination doping process
Authors: Kim SeonChang , Chung Roy ByungKyu 
Published: December 2024

Currently, there is active research on oxide semiconductors suitable for the next-generation integration technology, Monolithic 3D Integration (M3D). Among back-end-of-line (BEOL) compatible material candidates, SnO2, with its high mobility and wide bandgap (3.6 eV), is extensively utilized in the fields of solar cells and displays, semiconductors benefiting from excellent power efficiency, high price competitiveness, and transparency. Furthermore, the fluorine-doped tin oxide (FTO) is a highly transparent and conductive semiconductor, serving as a Transparent Conducting Oxide (TCO) widely utilized in various electronic and optoelectronic devices.
In this study, we fabricated SnO2 Thin Film Transistors (TFTs) utilizing SnO2 deposited by Thermal-Atomic Layer Deposition (T-ALD) as the channel layer. Additionally, the surface of the SnO2 in the Source/Drain regions was n+ doped through fluorination to enhance ohmic characteristics between the electrode and the channel layer. In this process, we have successfully fabricated SnO2 TFTs demonstrating excellent electrical characteristics, with a very high on/off current ratio exceeding 1013 and a low Subthreshold Swing (S.S) of 0.18 V/dec, achieved by effectively controlling the conductivity of SnO2. These results emphasize the potential of ALD SnO2 channels for high-performance transistors that are compatible with back-end-of-line processes in Si technology.

Figure 1
(General Student Poster Award Winner, 3rd Place) Probing the Trends of Cation Interactions in Cation Exchange Membranes Using Raman Spectroscopy
Authors: Beswick Rebecca , Smith Wilson A 
Published: December 2024

Cation exchange membranes (CEMs) are an ion exchange polymer which selectively shuttles cations through their structure. CEMs are used for a wide range of electrically driven processes, including electrolysis, fuel cells, and electrodialysis. Historically, fluorinated polymers have been used as CEMs, with the most prevalent being Chemours’ Nafion polymer. These materials and their synthesis can produce harmful, long-lived environmental toxins that may provide challenges to scaling to meet material demand. Therefore, significant research is being directed towards finding non-fluorinated CEMs with similar functionality. One promising candidate has been sulfonated poly-ether-ether-ketone (SPEEK), which has similar ion exchange capabilities as Nafion, while being low cost and non-fluorinated.
In electrochemical reactors, the effect of different cations in electrolyte solutions has shown high importance for overall conductivity and can affect reaction selectivity, activity, and durability. The cations which move through the CEM (mobile ions) can interact with the fixed sulfonate functional groups on the polymer backbone. While there is significant research on mobile ion effects on the performance of Nafion1, far less work has been done in this area with SPEEK2. Additionally, there are no direct comparisons between Nafion and any non-fluorinated polymer on how the polymer backbone affects these mobile ion interactions.
One method to study CEM-ion interactions is with Raman Spectroscopy, which uses a monochromatic light to initiate and observe Raman scattering from matter. While Raman spectra have been obtained for Nafion, we have not found Raman spectra of SPEEK in the presence of different electrolyte compositions. Here, we use Raman spectroscopy paired with water uptake and conductivity measurements to compare the differences of how a variety of mobile cations (H+, NH4+, Li+, Na+, K+, Rs+, Cs+, Mg2+, Ca2+, Sr2+) interact with the fixed sulfonate functional groups found in Nafion and SPEEK. We report that the two polymers show differences in the strength of the interactions between the mobile ions and fixed groups, which leads to changes in physical properties, including water uptake and conductivity. With these findings, more informed decisions of the applications of fluorinated vs non-fluorinated polymers for various electrochemical purposes can be made.
Key References:
[1] Peng, J. Tian, M. Cantillo, N.M., and Zawodzinski, T., Electrochimica Acta.
282, 544–554 (2018).
[2] Pérez-Pérez, M. and Suleiman, D., Journ of Mem Science. 493, 414–427 (2015).
[3] Maier, M. Abbas, D. Komma, M. Mu’min, M.S. and Thiele, S., Böhm, T., Journ of Mem Science. 669, 121244 (2023).
Electrophoretic Deposition of High Entropy Metal Phosphate Nanoparticles for Efficient Oxygen Evolution Reaction in Alkaline Media
Authors: Lee Hyeonseok , Ha Don-Hyung 
Published: December 2024

Through electrolysis utilizing renewable energy sources such as solar and wind power, green hydrogen can be produced without unwanted byproducts. For efficient electrolysis, a high-performance oxygen evolution reaction (OER) catalyst is required. Transition metal-based catalysts in alkaline electrolysis have been extensively studied, offering not only their lower cost compared to noble metal catalysts including Pt, Ir, and Ru but also promising high stability and performance. Particularly, high entropy materials (HEMs) composed of five or more elements in a homogeneous mixture exhibit unique catalytic activity not solely explained by hydrogen adsorption energy, owing to the broadening and mixing of d-band centers of constituent elements. Furthermore, the overall stability of high-entropy materials (HEM) in catalytic reactions is attributed to solid-solution strengthening and the sluggish atomic diffusion effects resulting from their high entropy.
In this work, we fabricated high entropy nanoparticles, where multiple elements are uniformly mixed, via a reverse precipitation method. The precursor introduced into the precipitant promptly reacted, disregarding the distinct precipitation rates of individual elements, successfully forming a random and homogeneous single phase, including transition metals (M = Cr, Mn, Co, Fe, Ni, Cu, and Zn). To further enhance catalytic performance, additional different sized atoms such as Mo and W were also incorporated during the synthesis process leading to lattice distortion of the surface atomic structure.
To fabricate alkaline OER electrodes using synthesized catalysts, the Electrophoretic Deposition (EPD) method was utilized attaching nanoparticles onto substrates. The resulting catalyst electrodes exhibited optimized performance with two rounds of EPD process, each lasting 10 minutes at an applied voltage of 1000V on Ni foam. The electrode fabricated through EPD outperformed those made using drop casting with Nafion binder in experimental comparisons, demonstrating superior performance.
Simulation for Elucidating a Formation Mechanism of 6-Coordinated Si in Phosphate Glass
Authors: Sakakibara Arata , Tamura Tomoyuki 
Published: December 2024

Phosphate glasses are materials that are expected to have a wide range of applications, including highly ion-conductive materials in fuel cells and biomaterials that supply therapeutic ions. Diffusion of ions in glasses plays an important role in designing glasses for these applications. The diffusion of protons is one of the most important properties of fuel cells, and the diffusion of network-modified cations such as Na+ and Ca2+ ions is closely related to glass dissolution and hydration reactions. In general, these diffusion properties are strongly dependent on the atomic-scale glass structure. We found that the difference in the morphology of PO4 tetrahedra (P-Qn
: number of bridging oxygen) greatly affects the diffusion of protons and Na+ ions in phosphate glass, where these ions can diffuse much more easily near P-Q2
than near P-Q3
, and suggested that ionic conductivity and glass solubility can be designed by controlling the P-Qn
distribution of phosphate glasses [1]. We also suggested that the P-Qn
distribution can be controlled using 6-coordinated Si (6cSi), which is formed in phosphate glasses containing more than 40 mol% P2O5 [2]. However, the formation mechanism of 6cSi is not clear. In this study, we aim to elucidate the formation mechanism of 6cSi in phosphate glasses based on first-principles molecular dynamics (MD) simulations.
The glass models for 55.0P2O5-21.3SiO2-23.7Na2O (mol%) were generated by quenching from the melt using classical MD simulations with the DL POLY [3] program. Subsequently, first-principles MD simulations using the SIESTA code [4] were performed to observe the reaction process from 4cSi to 5/6cSi. Atomic energies were calculated using orbital decomposition of the total energy by the OpenMX code [5]. For these electronic structure calculations, a localized basis with the GGA-PBE functional was used.
In obtained models, atomic energies for non-bridging oxygen (NBO) are higher than those for bridging oxygen (BO). In the first-principles MD simulation, the formation of chemical reaction from "4cSi + P-Q2
" to " 5/6cSi + P-Q3
" was observed as shown in Fig. 1. The energy decreases by the change from a NBO in P-Q2
to a BO in P-Q3
is larger than the energy increase by the change for 4cSi to 5c/6cSi.
It will be possible to design highly functional glasses by applying the 6cSi formation mechanism and controlling the amount of 6cSi formed.
Reference:[1] K. Takada, T. Tamura, H. Maeda, and T. Kasuga, Phys. Chem. Chem. Phys. 23, 14580 (2021). [2] K. Takada, T. Tamura ,and T. Kasuga, RSC Adv. 12, 35043 (2022). [3]T. Todorov et al., J. Chem. 16, 1911 (2006). [4] J. Solar et al., J. Phys. Cond. Matt. 14, 2745 (2000). [5] T. Ozaki, Phys. Rev. B 67, 155108 (2003).

Figure 1