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Tanahashi Keita

Faculty of Engineering　Center for Advanced Research of Energy and Materials　Laboratory of Energy MediaSpecially Appointed Assistant Professor

Researcher basic information

■ Degree
  • Ph.D., Hokkaido University, Mar. 2024
■ URL
researchmap URLホームページURL■ Various IDs
Researcher number
  • 31025696
ORCID IDJ-Global ID■ Research Keywords and Fields
Research Keyword
  • Energy Saving
  • Perovskite
  • Solution combustion synthesis
  • Latent heat storage
  • Oxygen storage materials
Research Field
  • Nanotechnology/Materials, Energy chemistry

Career

■ Career
Career
  • Apr. 2025 - Present
    Hokkaido University, Faculty of Engineering Center for Advanced Research of Energy and Materials Laboratory of Energy Media, Specially Appointed Assistant Professor, Japan
  • Apr. 2023 - Mar. 2025
    日本学術振興会特別研究員, Japan
Educational Background
  • Apr. 2019 - Mar. 2024, Hokkaido University, Graduate School of Engineering, Division of Materials Science and Engineering, Japan
  • Apr. 2015 - Mar. 2019, Hokkaido University, School of Engineering, Department of Applied Science and Engineering, Japan
  • Apr. 2012 - Mar. 2015, 北海道札幌南高等学校, Japan

Research activity information

■ Papers
  • Microencapsulation of Zn Phase Change Material via Dry Synthesis Method and Its Shell Formation Mechanism
    Kei Kotani; Melbert Jeem; Yuto Shimizu; Tomokazu Nakamura; Joshua Chidiebere Mba; Keita Tanahashi; Takahiro Nomura
    Energy & Fuels, 30 Jul. 2026
    Scientific journal
  • Kinetic Enhancement of Oxygen Storage in Ca2AlMnO5+δ via Yttrium-Induced Thermodynamic Tuning
    Keita Tanahashi; Hidekazu Naya; Yusei Omura; Yu Matsuba; Melbert Jeem; Minako Kondo; Yuji Kunisada; Norihito Sakaguchi; Takahiro Nomura
    Chemistry of Materials, 12 May 2026
    Scientific journal
  • Mechanical Microencapsulation and Shell Formation Mechanism of High Working Temperature Al-25Si Alloy Phase Change Material
    Joshua Chidiebere Mba; Kaixin Dong; Keita Tanahashi; Yuto Shimizu; Tomokazu Nakamura; Melbert Jeem; Takahiro Nomura
    ACS Sustainable Chemistry & Engineering, 02 Mar. 2026
    Scientific journal
  • Sensible/latent hybrid heat storage material using Solar Salt and Al–Cu–Si alloy-based phase change material
    Yuto Shimizu; Takahiro Kawaguchi; Keita Tanahashi; Tomokazu Nakamura; Melbert Jeem; Takahiro Nomura
    Chemical Engineering Journal, 508, 160832, 160832, Elsevier BV, Mar. 2025
    Scientific journal
  • Thermo-regulating effect of Al–Si microencapsulated phase change material-based catalyst support on ammonia decomposition
    Cholila Tamzysi; Yuto Shimizu; Tomokazu Nakamura; Melbert Jeem; Keita Tanahashi; Takahiro Kawaguchi; Kengo Mimura; Ade Kurniawan; Takahiro Nomura
    Reaction Chemistry & Engineering, Royal Society of Chemistry (RSC), 2025
    Scientific journal, Thermo-regulating ability of the MEPCM catalyst on ammonia decomposition.
  • High-temperature composite phase change material with “concrete-like” strength even beyond the eutectic temperature
    Yuto Shimizu; Takahiro Kawaguchi; Joshua Chidiebere Mba; Tomokazu Nakamura; Keita Tanahashi; Melbert Jeem; Takahiro Nomura
    Journal of Materials Chemistry A, 13, 36, 30382, 30398, Royal Society of Chemistry (RSC), 2025
    Scientific journal, A latent heat thermal energy storage composite with an Al–Cu–Si alloy-based microencapsulated phase change material has been developed. This composite exhibits a high compressive strength of 32 MPa, even when the internal alloy is in a liquid state.
  • Novel microencapsulated ternary eutectic alloy-based phase change material
    Yuto Shimizu; Shunsuke Cho; Takahiro Kawaguchi; Keita Tanahashi; Kaixin Dong; Tomokazu Nakamura; Ade Kurniawan; Melbert Jeem; Takahiro Nomura
    Journal of Energy Storage, 75, 109535, Elsevier BV, Jan. 2024
    Scientific journal
  • Oxygen Separation Performance of Ca2AlMnO5+δ as an Oxygen Storage Material for High-Temperature Pressure Swing Adsorption
    Tanahashi Keita; Omura Yusei; Naya Hidekazu; Kunisada Yuji; Sakaguchi Norihito; Kurniawan Ade; Nomura Takahiro
    ISIJ International, 62, 12, 2578, 2586, The Iron and Steel Institute of Japan, 15 Dec. 2022
    English, High-temperature pressure swing adsorption (HT-PSA) is a promising energy-saving approach for oxygen production from air. Ca2AlMnO5+δ, a Brownmillerite-type perovskite, is a promising sorbent for HT-PSA because of its remarkably high oxygen storage capacity (up to 3.3 wt%). In this study, we investigated the redox thermodynamics of Ca2AlMnO5+δ by pressure–composition–temperature (PCT) measurements and investigated the HT-PSA performance of Ca2AlMnO5+δ pellets in a 100 g-scale packed-bed-type reactor. PCT measurements revealed that Ca2AlMnO5+δ can reversibly separate 2.2 wt% of oxygen per cycle under equilibrium conditions between ambient oxygen partial pressure and 5×10−4 MPa at 525°C. However, in a 5 min switching HT-PSA test, Ca2AlMnO5+δ pellets were able to reversibly separate less than 1 wt% oxygen per cycle, which is significantly lower than that estimated from the thermodynamic properties of Ca2AlMnO5+δ. On the other hand, the exothermic oxygen storage and endothermic oxygen release reactions cause significant temperature variation of the packed bed. This study clarifies that, in order to increase the energy efficiency of oxygen separation by HT-PSA, there is a need to compensate for the heat of reaction, which changes the reactor temperature in a direction that interferes with the reaction.
  • Sr-Doped Ca2AlMnO5 + δ for Energy-Saving Oxygen Separation Process
    Keita Tanahashi; Yusei Omura; Hidekazu Naya; Kaho Miyazaki; Genki Saito; Yuji Kunisada; Norihito Sakaguchi; Takahiro Nomura
    ACS Sustainable Chemistry & Engineering, 9, 28, 9317, 9326, American Chemical Society (ACS), 07 Jul. 2021
    Scientific journal, Pressure swing adsorption (PSA) is expected to replace the currently used energy-intensive cryogenic distillation process for oxygen separation. For realizing an energy-saving PSA, an oxygen storage material (OSM) with a high oxygen storage capacity and narrow pressure swing gap during reversible oxygen storage and release is necessary. While Ca 2 AlMnO 5 is a promising candidate for PSA, it exhibits a large pressure hysteresis loop during oxygen storage and release. In this study, we investigated the effect of Sr doping of the Ca sites of Ca 2 AlMnO 5 (Ca 2– x Sr x AlMnO 5 ) on the phase compositions and oxygen storage/release performance with the aim of realizing an optimum OSM for the PSA process. From the results of structural refinement, while the oxygen release phase has a Brownmillerite (BM) structure ( n = 1) at 0 ≤ x ≤ 1.0, BM ( n = 3) and oxygen-defective perovskite were found to be the main structures in the oxygen storage phase at 0 ≤ x < 0.50 and 0.50 ≤ x ≤ 1.0, respectively. The oxygen storage/release temperature obtained from the thermogravimetry curves decreased in the 0 ≤ x < 0.50 range and increased in the 0.50 ≤ x ≤ 1.0 range with increasing x . This difference may be attributed to the structural differences in the storage phase. The pressure–composition–temperature (PCT) analysis by Sieberts’ method was applied to the OSM. Although PCT curves exhibited a remarkable decrease in hysteresis in the PSA process as x increased, the difference between onset and offset temperatures for each oxygen storage/release reaction broadened. A new evaluation method to optimize x of Ca 2– x Sr x AlMnO 5 and operating condition in the PSA process using the OSM was also examined. Plots of the pressure change required to release oxygen versus the amount of oxygen extracted allow for the efficient determination of optimal composition and working temperature. Ca 1.2 Sr 0.8 AlMnO 5 ( x = 0.80), which exhibited excellent repetition durability, was found to be optimal in this evaluation. The ideal PSA oxygen ...
  • Co-appearance of superconductivity and ferromagnetism in a Ca2RuO4 nanofilm crystal
    Hiroyoshi Nobukane; Kosei Yanagihara; Yuji Kunisada; Yunito Ogasawara; Kakeru Isono; Kazushige Nomura; Keita Tanahashi; Takahiro Nomura; Tomohiro Akiyama; Satoshi Tanda
    Scientific Reports, 10, 1, 3462, 3462, Springer Science and Business Media LLC, 26 Feb. 2020, [International Magazine]
    English, By tuning the physical and chemical pressures of layered perovskite materials we can realize the quantum states of both superconductors and insulators. By reducing the thickness of a layered crystal to a nanometer level, a nanofilm crystal can provide novel quantum states that have not previously been found in bulk crystals. Here we report the realization of high-temperature superconductivity in Ca2RuO4 nanofilm single crystals. Ca2RuO4 thin film with the highest transition temperature Tc (midpoint) of 64 K exhibits zero resistance in electric transport measurements. The superconducting critical current exhibited a logarithmic dependence on temperature and was enhanced by an external magnetic field. Magnetic measurements revealed a ferromagnetic transition at 180 K and diamagnetic magnetization due to superconductivity. Our results suggest the co-appearance of superconductivity and ferromagnetism in Ca2RuO4 nanofilm crystals. We also found that the induced bias current and the tuned film thickness caused a superconductor-insulator transition. The fabrication of micro-nanocrystals made of layered material enables us to discuss rich superconducting phenomena in ruthenates.
■ Other Activities and Achievements
■ Lectures, oral presentations, etc.
  • Fundamental study on passive thermal regulation of pressure swing oxygen production process using microencapsulated phase change materials
    Keita Tanahashi; Tomokazu Nakamura; Takahiro Kawaguchi; Takahiro Nomura
    The 62nd National Heat Transfer Symposium/HTSJ International Heat Transfer Symposium, 15 May 2025, English, Oral presentation
    14 May 2025 - 17 May 2025
  • Reaction heat management technology in PSA process using oxygen storage materials
    棚橋慧太; 能村貴宏
    材料とプロセス(CD-ROM), 2025
    2025 - 2025
  • Microencapsulated Phase Change Materials with Hybrid Latent Heat Storage and Oxygen Storage Functions
    K. Tanahashi; M. Jeem; T. Nomura
    2024 MRS Fall Meeting and Exhibit, 03 Dec. 2024, English, Poster presentation
    01 Dec. 2024 - 06 Dec. 2024
  • Thermochemical energy storage properties of Ca2AlMnO5+δ
    K. Tanahashi; Y. Matsuba; M. Jeem; T. Nomura
    Enerstock 2024, 05 Jun. 2024, English, Oral presentation
    05 Jun. 2024 - 07 Jun. 2024
  • Thermal storage performance of Ca2AlMnO5+δ as chemical heat storage material
    棚橋慧太; 松葉悠; JEEM Melbert; 能村貴宏
    材料とプロセス(CD-ROM), 2024
    2024 - 2024
  • Improving CO2 durability of an oxygen storage material by surface modification
    棚橋慧太; 松葉悠; JEEM Melbert; 能村貴宏
    日本セラミックス協会秋季シンポジウム講演予稿集(Web), 2024
    2024 - 2024
  • Ca2AlMnO5+δの酸素貯蔵・放出反応に対する潜熱蓄熱材による熱制御の効果
    棚橋慧太; 松葉悠; 國貞雄治; 坂口紀史; 能村貴宏
    化学工学会年会研究発表講演要旨集(CD-ROM), 2023
    2023 - 2023
  • Ca2AlMnO5+δの酸素貯蔵・放出反応に対する化学ドープの効果
    棚橋慧太; 松葉悠; 國貞雄治; 坂口紀史; 能村貴宏
    化学工学会秋季大会研究発表講演要旨集(CD-ROM), 2023
    2023 - 2023
  • Ca2AlMnO5+δの酸素吸脱蔵反応特性の改善
    棚橋慧太; 松葉悠; 國貞雄治; 坂口紀史; 能村貴宏
    化学工学会秋季大会研究発表講演要旨集(CD-ROM), 2022
    2022 - 2022
  • Size effect on the crystalline and magnetic phases of Ca2RuO4
    棚橋慧太; 延兼啓純; 坂口紀史; 迫田將仁; 丹田聡; 能村貴宏
    応用物理学会北海道支部/日本光学会北海道支部合同学術講演会講演予稿集, 2021
    2021 - 2021
  • 圧力スウィング型空気分離プロセスにおける酸素吸蔵材料の反応・熱挙動の調査
    大村湧生; 棚橋慧太; 納谷英和; KURNIAWAN Ade; 能村貴宏
    化学工学会秋季大会研究発表講演要旨集(CD-ROM), 2021
    2021 - 2021
  • 省エネルギー空気分離プロセスへ向けた酸素貯蔵材料Ca2-xSrxAlMnO5+δのSrドープ量最適化
    棚橋慧太; 大村湧生; 納谷英和; 齊藤元貴; KURNIAWAN Ade; 國貞雄治; 坂口紀史; 能村貴宏
    化学工学会秋季大会研究発表講演要旨集(CD-ROM), 2021
    2021 - 2021
  • 酸素吸蔵材料Ca2Al1-xYxMnO5+δの酸素吸脱蔵特性調査
    納谷英和; 大村湧生; 棚橋慧太; 坂口紀史; 國貞雄治; 能村貴宏
    化学工学会秋季大会研究発表講演要旨集(CD-ROM), 2021
    2021 - 2021
  • Modulation of lattice and magnetism by nanocrystallization of Ca2RuO4
    棚橋慧太; 延兼啓純; 迫田將仁; 丹田聡; 能村貴宏
    応用物理学会秋季学術講演会講演予稿集(CD-ROM), 2020
    2020 - 2020
  • Ferromagnetic phase emerged by controlling oxygen content in Ca2RuO4 nanocrystals
    棚橋慧太; 能村貴宏; 延兼啓純; 迫田將仁; 丹田聡
    応用物理学会春季学術講演会講演予稿集(CD-ROM), 2020
    2020 - 2020
  • 層状ルテニウム酸化物ナノスケール結晶の輸送現象
    礒野翔; 延兼啓純; 柳原興世; 小笠原優仁; 國貞雄治; 棚橋慧太; 能村貴宏; 秋山友宏; 秋山友宏; 野村一成; 丹田聡
    日本物理学会講演概要集(CD-ROM), 2019
    2019 - 2019
  • Ca2RuO4の粒径と構造転移の関係性
    棚橋慧太; 能村貴宏; 延兼啓純; 迫田將仁; 丹田聡; 秋山友宏
    応用物理学会秋季学術講演会講演予稿集(CD-ROM), 2019
    2019 - 2019
■ Affiliated academic society
  • Jan. 2024 - Present
    日本鉄鋼協会
  • Jul. 2021 - Present
    日本セラミックス協会
  • Jun. 2021 - Present
    化学工学会
  • Jun. 2019 - Dec. 2024
    応用物理学会
■ Research Themes
  • Elucidation of the oxygen storage/release reaction mechanism of large-capacity oxygen storage materials and performance improvement for realizing energy-saving oxygen production
    Grants-in-Aid for Scientific Research
    25 Apr. 2023 - 31 Mar. 2025
    棚橋 慧太
    本研究では酸素貯蔵材料を用いた省エネ酸素製造プロセス実現を大目標とし、そのプロセス効率を支配する酸素貯蔵材料の酸素貯蔵・放出性能向上を目指す。そのために代表的な酸素貯蔵材料の酸素貯蔵・放出メカニズムの解明と、酸素貯蔵材料に対する各種アプローチによる酸素貯蔵・放出特性の熱力学的、速度論的変化を目的とする。さらに、実際の酸素分離プロセスを想定し充填層を用いた実験室スケールでの酸素製造試験を行い、操業条件の最適化やプロセスに基づいた酸素貯蔵材料の改良を行う。
    本年度は特にCa2AlMnO5+δ（CAMO）に着目し、その酸素貯蔵・放出反応速度論調査と元素ドープによる酸素貯蔵・放出性能特性の変化について調査した。反応速度調査から、CAMOにて課題である反応速度の遅さを改善する方法の1つとして酸素貯蔵・放出反応平衡温度を上昇させることが示唆された。そこで、酸素貯蔵・放出反応温度の上昇が予想されるドープ元素を第一原理計算にて探索した。続いて、計算によって反応温度上昇が予測された元素をドープしたCAMOを実際に合成し、その酸素貯蔵・放出特性を調査した。結果として、酸素貯蔵反応と放出反応のどちらも平衡温度が上昇し、CAMOよりも高速な酸素貯蔵・放出サイクルを可能とすることが判明した。
    Japan Society for the Promotion of Science, Grant-in-Aid for JSPS Fellows, Hokkaido University, 23KJ0033