研究者詳細 - 寺西　貴志

論文 - 寺西　貴志

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Fabrication of Mullite Based Porous Ceramics with Favorable Creep Resistance Utilizing Superplastically Foaming Method

Ryotaro Yokota, Sakiho Arizuka, Wakuya Miyamoto, Shinya Kondo, Takashi Teranishi, Akira Kishimoto

Journal of the Japan Society of Powder and Powder Metallurgy 72 ( Supplement ) S761 - S766 2025年3月

Permittivity and remanent polarization contributions to the electrocaloric effect in (Ba, Sr)TiO3 under unipolar field

Yukiya Tanaka, Ryo Iguchi, Takashi Teranishi, Shinya Kondo, Akira Kishimoto

Applied Physics Letters 126 ( 13 ) 2025年3月

掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Publishing

The electrocaloric effect (ECE)-induced temperature change (ΔT) in (Ba, Sr)TiO3-based ferroelectrics under unipolar electric fields was analyzed from the separate contributions of the dielectric constant (ε) and remanent polarization (Pr) based on the Maxwell relation. Consideration of the contributions of both ε and Pr is particularly important in a unipolar electric field operation, such as on/off field switching used in device applications. Direct ΔT measurements were also performed based on the lock-in thermography technique to verify the accuracy of the ΔT intensity estimated by the indirect method. The indirect and direct ΔT values were largely consistent. The ΔT intensity near the peak temperature of ΔT was dominated by the Pr contribution; a large ∂Pr/∂T was necessary to increase the overall ΔT magnitude. In contrast, a large ∂ε/∂T was essential to expand the operating temperature range of ΔT at temperatures higher than the dielectric maximum temperature. Quantitative understanding of the contributions of both ε and Pr to ΔT in unipolar electric fields is expected to guide the search for materials with a superior ECE.

DOI： 10.1063/5.0259805

Dynamic domain motion enhancing electro-optic performance in ferroelectric films

Shinya Kondo, Kazuki Okamoto, Osami Sakata, Takashi Teranishi, Akira Kishimoto, Takanori Nagasaki, Tomoaki Yamada

Applied Physics Letters 126 ( 1 ) 2025年1月

掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Publishing

With the rapid advancement of information technology, there is a pressing need to develop ultracompact and energy-efficient thin-film-based electro-optic (EO) devices. A high EO coefficient in ferroelectric materials is crucial. However, substrate clamping can positively or negatively influence various physical properties, including the EO response of these films, thus complicating the development of next-generation thin-film-based devices. This study demonstrates that reversible dynamic domain motion, achieved through substrate clamping, significantly enhances the EO coefficient in epitaxial ferroelectric rhombohedral Pb(Zr, Ti)O3 thin films, where the (111) and (111¯) domains coexist with distinct optical axes. In principle, this approach can be applied to different film-substrate systems, thereby contributing to the advancement of sophisticated EO devices based on ferroelectrics.

DOI： 10.1063/5.0244707

Doping Rare Earth Dependent Mechanical Strength Improvement on Reduction of Ceria Based Solid Electrolytes

Taiga UEHARA, Shinya KONDO, Takashi TERANISHI, Akira KISHIMOTO

Journal of the Japan Society of Powder and Powder Metallurgy 71 ( 11 ) 529 - 533 2024年11月

Colossal Dielectric Constant of Nanocrystalline/Amorphous Homo-Composite BaTiO3 Films Deposited via Pulsed Laser Deposition Technique

Shinya Kondo, Taichi Murakami, Loick Pichon, Joël Leblanc-Lavoie, Takashi Teranishi, Akira Kishimoto, My Ali El Khakani

Nanomaterials 14 ( 20 ) 1677 - 1677 2024年10月

掲載種別：研究論文（学術雑誌）出版者・発行元：MDPI AG

We report the pulsed laser deposition (PLD) of nanocrystalline/amorphous homo-composite BaTiO3 (BTO) films exhibiting an unprecedented combination of a colossal dielectric constant (εr) and extremely low dielectric loss (tan δ). By varying the substrate deposition temperature (Td) over a wide range (300–800 °C), we identified Td = 550 °C as the optimal temperature for growing BTO films with an εr as high as ~3060 and a tan δ as low as 0.04 (at 20 kHz). High-resolution transmission electron microscopy revealed that the PLD-BTO films consist of BTO nanocrystals (~20–30 nm size) embedded within an otherwise amorphous BTO matrix. The impressive dielectric behavior is attributed to the combination of highly crystallized small BTO nanograins, which amplify interfacial polarization, and the surrounding amorphous matrix, which effectively isolates the nanograins from charge carrier transport. Our findings could facilitate the development of next-generation integrated dielectric devices.

DOI： 10.3390/nano14201677

Polarization at the compositional interface in Nb-doped metastable TiO₂-SnO₂ solid solutions

Takashi Teranishi, Junsuke Satake, Shinya Kondo, Akira Kishimoto

Japanese Journal of Applied Physics 63 ( 7 ) 07SP05 - 07SP05 2024年7月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

Polarization architecture was incorporated into metastable Nb-doped TiO₂-SnO₂ to deliver electron accumulation at the localized TiO₂-SnO₂ compositionally fluctuating interface. Specimens were quenched from various holding temperatures to ambient temperatures in air to avoid bimodal decomposition into TiO₂ and SnO₂ endmembers. At the lowest sintering temperature of 1,400 °C, the mixed phase containing TiO₂- and SnO₂-rich compositions existed as an intermediate state to the single-phase solid solution. The phase boundary became more ambiguous with increasing sintering temperatures, and the compositional fluctuation size reduced to single nanometers at 1,500 °C. The permittivity due to the interfacial polarization, ε _interface, increased steadily with increasing sintering temperature. The larger ε _interface values at higher temperatures are attributed to the greater density of the compositionally fluctuating phase interface, which leads to greater electron accumulation at the energy barrier between the two semiconducting layers.

DOI： 10.35848/1347-4065/ad5e8d

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ad5e8d/pdf

Enhanced Charge Accumulation in Activated Carbon via the Dielectric Interface

Yuji Toyota, Takashi Teranishi, Kosuke Fukui, Masakuni Takahashi, Ji Qiuyu, Shinya Kondo, Masanobu Nakayama, Akira Kishimoto

ACS Applied Energy Materials 7 ( 4 ) 1440 - 1447 2024年2月

外場としてのミリ波を援用した高温電気化学デバイスの特性変化

Takuro FUJIWARA, Takashi TERANISHI, Akira KISHIMOTO, Seiichi SUDA

Journal of the Japan Society of Powder and Powder Metallurgy 70 ( 9 ) 387 - 391 2023年9月

負膨張材料を分散させた表面層を持つセラミックス積層体の耐熱衝撃性

Takaya UENO, Shinya KONDO, Takashi TERANISHI, Akira KISHIMOTO

Journal of the Japan Society of Powder and Powder Metallurgy 70 ( 8 ) 376 - 379 2023年8月

Polarization contributions to DC bias characteristics of nanograined BaTiO₃-based ceramics

Takashi Teranishi, Ruku Ozaki, Shinya Kondo, Akira Kishimoto

Japanese Journal of Applied Physics 62 ( SM ) SM1015 - SM1015 2023年8月

掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Publishing

Abstract

The domain configuration contributions to the DC bias characteristics of nanograined BaTiO₃ were clarified. Domain boundaries became more ambiguous with decreasing grain size (g.s.), whereas domain patterns partially vanished because of the reduction in BT ferroelectricity, in the g.s. range <1 μm. Additionally, intergranular stress increased with decreasing g.s., resulting in crystal lattice hardening in the vicinity of the domain walls (DWs) and suppression of dipole fluctuations in the DWs. These domain structural variations with the domain size (d.s.) reduced permittivity in the absence of a DC electric field, resulting in improvements in permittivity depressions in an electric field (Δε). Magnesium substitution slightly decreased the d.s. The increase in DW density upon Mg loading implied defect pairs, ${ { \rm{Mg } } }_{ { \rm{Ti } } }^{"}$–${ { \rm{V } } }_{ { \rm{o } } }^{\bullet \bullet },$ which acted as new DW pinning centers, thereby subdividing the DWs. The Δε notably improved via Mg loading, because a defect pair effectively pins the DWs under the electric field.

DOI： 10.35848/1347-4065/ace6a8

その他リンク： https://iopscience.iop.org/article/10.35848/1347-4065/ace6a8/pdf

Spinodal decomposition-derived giant polarization in TiO2–SnO2 generated from a metastable phase 査読

Takashi Teranishi, Hideki Matsui, Shinya Kondo, Akira Kishimoto

Journal of Applied Physics 133 ( 17 ) 2023年5月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：{AIP} Publishing

<jats:p>Spinodal decomposition (SD) was incorporated into Nb-doped metastable TiO2–SnO2 to achieve giant interfacial polarization. The dielectric characteristics were analyzed using an equivalent circuit involving electron migration, where the SD bulk is given by the universal dielectric response relation. Both the Nb–TiO2 and the Nb–SnO2 layers showed semiconductive behaviors. With increasing SD treatment temperature, the SD volume fraction increased, as did cation interdiffusion at the SD interface, resulting in a large dielectric loss. The optimal SD temperature was determined as 1100 °C, where the Maxwell–Wagner capacitance showed a very high value of 44.6 μF corresponding to the permittivity at the lowest frequency exceeding 106. Such colossal polarization was considered due to an accumulation of trapped electrons at the Schottky barrier at SD layers with different conductivities.</jats:p>

DOI： 10.1063/5.0144782

Direct measurement of electrocaloric effect based on multi-harmonic lock-in thermography

Ryo Iguchi, Daisuke Fukuda, Jun Kano, Takashi Teranishi, Ken-ichi Uchida

Applied Physics Letters 122 ( 8 ) 2023年2月

掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Publishing

We report on a direct measurement method for electrocaloric effects, the heating/cooling upon application/removal of an electric field in dielectric materials, based on a lock-in thermography technique. By use of sinusoidal excitation and multi-harmonic detection, the actual temperature change can be measured by a single measurement in the frequency domain even when the electrocaloric effect shows a nonlinear response to the excitation field. We demonstrated the method by measuring the temperature dependence of the electric-field-induced temperature change in two Sr-doped BaTiO3 systems with different ferroelectric-paraelectric phase transition temperatures, where we introduce the procedure for extracting the pure electrocaloric contribution free from heat losses and Joule heating due to leakage currents. This method can be used irrespective of the type of dielectric material and enables simultaneous estimation of the polarization change and power dissipation during the application of an electric field, making it a convenient imaging measurement method for the electrocaloric effect.

DOI： 10.1063/5.0137686

Density Functional Theory and Machine Learning-Based Analyses for Improved Surface Stability of a BaTiO3-Coated LiCoO2 Positive Electrode Material

Kunihiro Ishida, Naoto Tanibata, Hayami Takeda, Masanobu Nakayama, Takashi Teranishi, Naoki Watanabe

PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 259 ( 9 ) 2022年9月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY-V C H VERLAG GMBH

The application of oxide coating on the surfaces of active cathode materials is an effective method for improving the electrochemical durability of lithium-ion batteries because it suppresses oxygen gas release from the surface of the cathode material. This report summarizes a study conducted on verifying the suppression of oxygen release from a LiCoO2 cathode material using BaTiO3 (BT), which has recently attracted attention as a new coating material. The use of first-principles calculations and machine learning as verification methods is described. In addition to the discussion of interfacial properties based on atomic- and electronic-level considerations, comprehensive verification of the interface with several junction patterns is described. The verification results suggest that the desorption of oxygen from the surface of the active material is hindered by the oxide coating, indicating the effectiveness of BT as a coating material.

DOI： 10.1002/pssb.202100526

Electric Potential Mapping of All-Solid-State Lithium Ion Batteries using A Terahertz Chemical Microscope

Ryota Tomie, Taketo Yamaguchi, Masashi Shimizu, Kashu Hamada, Takashi Teranishi, Hidetoshi Nose, Masaki Kobayashi, Jin Wang, Kenji Sakai, Toshihiko Kiwa

2022 47TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER AND TERAHERTZ WAVES (IRMMW-THZ 2022) 2022年8月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：IEEE

A terahertz (THz) chemical microscope has been developed to measure the electric potential distribution of liquid phase lithium ion batteries (LIBs) during charging and discharging. A LIB was fabricated on a sensing plate, which consists of SiO2 and Si films on a sapphire substrate, to generate THz pulses by a laser irradiation. Since the amplitude of THz is proportional to the electric potential on the sensing plate, the electric potential distribution of the lithium ion battery on the sensing plate could be visualized. In this study, the electric potential distribution across a conventional all-solid-state LIB was measured by immobilizing the LIB on the sensing plate using epoxy resin. The distribution of the electric potentials of the battery was clearly visualized by the TCM. This result indicates that the TCM could be one of useful tools for the development high performance batteries.

DOI： 10.1109/IRMMW-THz50927.2022.9896121

Ceria-based solid electrolyte exhibits superior mechanical and electric properties compared to zirconia-based solid electrolyte

Akira Kishimoto, Taiga Umemura, Shinya Kondo, Takashi Teranishi

CERAMICS INTERNATIONAL 48 ( 15 ) 21824 - 21831 2022年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：ELSEVIER SCI LTD

The mechanical strength and electrical characteristics of 10 mol% gadolinium (Gd)-doped ceria (10GDC) and gadolinium-samarium (Gd-Sm) co-doped ceria ceramics treated by contact reduction were investigated. The observed increased strength of 10GDC was similar to the strength previously reported for ceria with and without Sm doping. X-ray photoelectron spectroscopy revealed that only the surface was reduced in the strengthened material. In addition, the strengthened ceramic displayed improved hardness at low test loads, which suggested the formation of a surface compression layer. The reducing conditions did not affect the electrical conductivity of the 10GDC material. Co-doping with 10 mol% each of Gd and Sm improved strength and conductivity compared with 10GDC and 20GDC. When the co-doped material was reduced, the electric conductivity remained identical; however, the mechanical strength improved, exceeding the strength of zirconia.

DOI： 10.1016/j.ceramint.2022.04.166

Case report of a Japanese patient with chronic renal failure who developed SARS-CoV-2 in a hospital cluster during treatment for acute respiratory failure: An autopsy report

Yoshifumi Amari, Satoshi Morimoto, Takashi Teranishi, Mai Ohata, Atsushi Takeshita, Hiroshi Hirano, Hitoshi Kobayashi

CLINICAL CASE REPORTS 10 ( 7 ) 2022年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

This article reports a clinical and histopathological perspective which noted not only COVID-19 pneumonia but also exacerbation of chronic renal failure potentially caused by thrombus in the kidney, possibly COVID-19-related lesions. The accumulation of autopsy cases will elucidate the pathogenesis of COVID-19 and aid in the development of effective therapeutics.

DOI： 10.1002/ccr3.6024

Capacity retention improvement of LiCoO2 cathodes via their laser-ablation-based nanodecoration by BaTiO3 nanoparticles

Takashi Teranishi, Yumi Yoshikawa, Joel Leblanc-Lavoie, Nazar Delegan, Ibrahima Ka, Akira Kishimoto, My Ali El Khakani

JOURNAL OF APPLIED PHYSICS 131 ( 12 ) 124105 - 124105 2022年3月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Publishing

We report on the pulsed-laser-deposition (PLD) based nanodecoration of LiCoO₂ (LCO) with BaTiO₃ (BTO) nanoparticles (NPs) aimed at increasing the density of dielectric-active material–electrolyte triple-phase interfaces (TPIs). The BTO-NPs were deposited onto LCO at different numbers of laser pulses (N_Lp) and two different schemes, namely, (i) BTO-NP deposition on the surface of the precast cathode (“2D-nanodecoration”) and (ii) BTO-NP decoration of LCO powder prior to its processing to form a working cathode (“3D-nanodecoration”). While the “2D-nanodecoration” mode was found to improve significantly the discharge capacity of the LCO cathodes (by ∼30 mAh/g for N_Lp ≥ 200), their capacity retention (CR) was modest. In contrast, the “3D-nanodecoration” scheme enabled not only the volumic nanodecoration of the LCO powder by BTO-NPs but also their subsequent annealing to improve their crystallinity. These 3D-nanodecorated LCO cathodes were found to exhibit significantly higher CR values. In particular, for N_Lp = 100 k, a CR (@10 °C) as high as 78% was achieved (∼47% higher than that of their sol–gel-processed cathode counterparts). Our results point out that three key ingredients (small BTO-NP size, high D_TPI, and high dispersibility of NPs on LCO) should be combined to ensure a high CR of BTO-NP-decorated LCO cathodes.

DOI： 10.1063/5.0075970

Evaluation of superplastic-foamed zirconia-based ceramics using foaming agent and a superplasticity facilitator derived from rice husk

Akira Kishimoto, Kentaro Tanaka, Takashi Teranishi

JOURNAL OF POROUS MATERIALS 29 ( 1 ) 153 - 159 2022年2月

担当区分：最終著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：SPRINGER

The applicability of rice husks to solid phase foaming ceramics was assessed. Through an atmospheric heat treatment on silicon carbide based mixture produced by the reduction heat treatment of rice husks, the residual carbon was mostly eliminated, giving a foaming agent composed of approximately SiC and SiO2. Solid-phase foamed porous ceramics was fabricated using this rice husk-derived foaming agent and the properties were compared with that fabricated from commercially available SiC. The sample fabricated from the rice husk-derived foaming agent showed favorable performances in terms of both strength and heat insulating properties. In comparison with the sample fabricated by adding commercially available silica in addition to commercial SiC, the strength became comparable, however, its heat insulating property was still inferior to that using rice husk-derived foaming agent. The increase in mechanical strength can be ascribed to the suppression of the grain growth due to the added silica. The formed silica phase existing at the grain boundaries would affect the thermal conductivity.

DOI： 10.1007/s10934-021-01156-3

その他リンク： https://link.springer.com/article/10.1007/s10934-021-01156-3/fulltext.html

Ultrafast Ion Transport via Dielectric Nanocube Interface

Takashi Teranishi, Ryoji Yamanaka, Ken-ichi Mimura, Mika Yoneda, Shinya Kondo, Kazumi Kato, Akira Kishimoto

ADVANCED MATERIALS INTERFACES 9 ( 4 ) 2022年2月

担当区分：筆頭著者,　責任著者記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

Drastic enhancement in the high-rate capability of lithium-ion batteries to the level of supercapacitors while maintaining high energy density is required for next-generation power sources. Incorporating dielectric BaTiO3 (BTO)-based nanocubes (NCs) into the active materials-electrolyte interface provides an ultrafast charge transfer pathway via the dielectric layer. The highly dispersed NC-decorated LiCoO2 (LCO) treated at the optimized temperature of 600 degrees C displays significantly enhanced high-rate capability; the cell maintains 56.7 mAh g(-1) at 50C (1C = 160 mA g(-1)), which compares with null capacity at the same rate for bare LCO. Comparing the NCs with conventional sol-gel-derived nanoparticles, the capacity retention at 10C (vs 0.1C) steadily increases with increasing active materials-dielectric-electrolyte triple-phase interface (TPI) in the NC-decorated case, whereas the capacity retention decreases markedly at similar TPI density in the sol-gel case. In the sol-gel case, the amount of Li ions accumulating at the TPI greatly exceeds the maximum amount of Li ions involved in electron exchange through the redox reaction within the charge/discharge time. In the NC case, most Li ions at the TPI participate effectively in the redox reaction, which results in fast charge transfer since the TPI sites are abundantly supplied with Li ions.

DOI： 10.1002/admi.202101682

Development of impedance measurement of lithium ion batteries electrode using terahertz chemical microscope

Masashi Shimizu, Ryoji Yamanaka, Takashi Teranishi, Jin Wang, Kenji Sakai, Keiji Tsukada, Toshihiko Kiwa

ELECTRICAL ENGINEERING IN JAPAN 214 ( 4 ) 2021年12月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：WILEY

In recent years, with the spread of electric vehicles, improvement in the performance of lithium ion batteries has been required. Evaluation of the active material is important because the performance of the lithium ion battery is affected by the movement of lithium ions at the electrode active material-electrolyte interface. In this study, we fabricated a lithium ion battery with the sensing plate, which is a potential sensor, attached to the positive electrode, and evaluated lithium ion battery with a terahertz chemical microscope (TCM). As a result, we succeeded in measuring the potential distribution of the positive electrode during charging and discharging, and the local impedance.

DOI： 10.1002/eej.23355

その他リンク： https://onlinelibrary.wiley.com/doi/full-xml/10.1002/eej.23355

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