Faculty Profiles - NAKANISHI Kazuki

Papers - NAKANISHI Kazuki

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Double-Layered Perovskite Oxyfluoride Cathodes with High Capacity Involving O-O Bond Formation for Fluoride-Ion Batteries Reviewed

Miki H., Yamamoto K., Nakaki H., Yoshinari T., Nakanishi K., Nakanishi S., Iba H., Miyawaki J., Harada Y., Kuwabara A., Wang Y., Watanabe T., Matsunaga T., Maeda K., Kageyama H., Uchimoto Y.

Journal of the American Chemical Society Vol. 146 ( 6 ) page： 3844 - 3853 2024.2

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of the American Chemical Society

Developing electrochemical high-energy storage systems is of crucial importance toward a green and sustainable energy supply. A promising candidate is fluoride-ion batteries (FIBs), which can deliver a much higher volumetric energy density than lithium-ion batteries. However, typical metal fluoride cathodes with conversion-type reactions cause a low-rate capability. Recently, layered perovskite oxides and oxyfluorides, such as LaSrMnO4 and Sr3Fe2O5F2, have been reported to exhibit relatively high rate performance and cycle stability compared to typical metal fluoride cathodes with conversion-type reactions, but their discharge capacities (∼118 mA h/g) are lower than those of typical cathodes used in lithium-ion batteries. Here, we show that double-layered perovskite oxyfluoride La1.2Sr1.8Mn2O7−δF2 exhibits (de) intercalation of two fluoride ions to rock-salt slabs and further (de) intercalation of excess fluoride ions to the perovskite layer, leading to a reversible capacity of 200 mA h/g. The additional fluoride-ion intercalation leads to the formation of O-O bond in the structure for charge compensation (i.e., anion redox). These results highlight the layered perovskite oxyfluorides as a new class of active materials for the construction of high-performance FIBs.

DOI： 10.1021/jacs.3c10871

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PubMed

Unusual flexibility of transparent poly(methylsilsesquioxane) aerogels by surfactant-induced mesoscopic fiber-like assembly Reviewed

Ryota Ueoka, Yosuke Hara, Ayaka Maeno, Hironori Kaji, Kazuki Nakanishi, Kazuyoshi Kanamori

Nature Communications Vol. 15 ( 1 ) page： 461 2024.1

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Science and Business Media LLC

Abstract

High-performance thermal insulators represented by aerogels are regarded as one of the most promising materials for energy savings. However, significantly low mechanical strength has been a barrier for aerogels to be utilized in various social domains such as houses, buildings, and industrial plants. Here, we report a synthetic strategy to realize highly transparent aerogels with unusually high bending flexibility based on poly(methylsilsesquioxane) (PMSQ) network. We have constructed mesoscopic fine fiber-like structures of various sizes in PMSQ gels by the combination of phase separation suppression by tetramethylammonium hydroxide (TMAOH) and mesoscopic fiber-like assembly by nonionic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-b-PPO-b-PEO) type surfactant. The optimized mesoscale structures of PMSQ gels have realized highly transparent and resilient monolithic aerogels with much high bendability compared to those reported in previous works. This work will provide a way to highly insulating materials with glasslike transparency and high mechanical flexibility.

DOI： 10.1038/s41467-024-44713-5

Other Link： https://www.nature.com/articles/s41467-024-44713-5

Preparation of monolithic silica HPLC columns with truss-structured skeletons and embedded surfactant-templated mesopores Reviewed

Detani T., Morisato K., Ohira M., Nakanishi K.

Journal of Sol-Gel Science and Technology 2024

Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Sol-Gel Science and Technology

Monolithic macro/mesoporous silica gels have been prepared via a sol-gel process using triblock copolymer Pluronic P123 (EO20PO70EO20) as a structure-directing agent. In this synthesis, P123 not only induces phase separation to form macroporous structure but also acts as a supramolecular template to form mesopores with precisely controlled shape and size. Obtained was a monolithic silica composed of continuous truss-like columnar skeletons in which cylindrical mesopores are arranged in a 2D-hexagonal symmetry. These monolithic silica gels have extremely high porosity approaching 90% and exhibited high specific surface area and sharp pore size distribution as revealed by N2 sorption measurements. Combinations of the initial composition and the post-gelation treatment on wet gels allowed the control of physical properties of meso- and macropore structures. The monolithic HPLC columns prepared using these silica gels surface-modified by ODS (octadecylsilyl) ligands gave as many as 140,000 theoretical plates/m for the separation of alkylbenzenes in a reversed-phase mode. Very weak dependence of height equivalent to theoretical plate, H, on the mobile phase velocity was also recognized in comparison with conventional particle-packed columns. Graphical Abstract: (Figure presented.)

DOI： 10.1007/s10971-024-06595-3

Scopus

The Role of Nanoporous Adsorbents in the Circular Economy—Closing the Loop of Critical Materials Recovery Reviewed

Florek J., Negoro M., Hu Y., Kanamori K., Nakanishi K., Kleitz F.

Advanced Functional Materials 2024

Language：English Publishing type：Research paper (scientific journal) Publisher：Advanced Functional Materials

Due to the increase in the global population, industrialization, and the transition to climate neutrality through low-emission technologies, the pressure on critical materials (CMs) continues to grow. CMs are defined as materials with a significant risk of supply chain disruption and limited substitutability. In this context, rare-earth elements, platinum group metals, lithium, and cobalt are particularly crucial for the shift to carbon-free economy and sustainability. One of the important strategies to endorse the goal of carbon reduction is to promote the recycling of resources. As a solution, effective recovery strategies have been developed, such as solid-phase separation technologies based on advanced functional sorbents. This perspective article aims to provide a general assessment of the role of porous materials in closing the loop of critical materials recycling. Here, comprehensive insights are provided into recent development, design, and application of porous adsorbents commonly applied in solid-phase extraction systems. Their current research status and problems related to their future application are also highlighted. This review covers recent advances in porous and hierarchical silica-based materials, aerogels, covalent organic frameworks, metal–organic frameworks, and carbon-based adsorbents.

DOI： 10.1002/adfm.202409462

Scopus

Powdered Hierarchically Porous Silica Monoliths for the Selective Extraction of Scandium Reviewed

Brewer A., Reicher C., Manatschal O., Bai H., Nakanishi K., Kleitz F.

ACS Sustainable Chemistry and Engineering Vol. 11 ( 42 ) page： 15432 - 15439 2023.10

Language：English Publishing type：Research paper (scientific journal) Publisher：ACS Sustainable Chemistry and Engineering

Scandium (Sc) is a high value Critical Material that is most commonly used in advanced alloys. Due to current and potential supply limitations, there has been an international effort to find new and improved ways to extract Sc from existing and novel resources. Solid-phase extraction (SPE) is one promising approach for Sc recovery, particularly for use with low-grade feedstocks. Here, unfunctionalized, powdered hierarchically porous silica monoliths from DPS Inc. (DPS) are used for Sc extraction in batch and semicontinuous flow systems at model conditions. The sorbent exhibits excellent mass transfer properties, much like the whole monoliths, which should permit Sc to be rapidly recovered from large volumes of feedstock. The Sc adsorption capacity of the material is ∼142.7 mg/g at pH 6, dropping to ∼12.0 mg/g at pH 3, and adsorption is furthermore highly selective for Sc compared with the other rare earth elements (REEs). Under semicontinuous flow conditions, recovery efficiency is limited by a kinetic process. The primary mechanism responsible for the system’s slow approach to equilibrium is the Sc adsorption reaction kinetics rather than inter- or intraparticle diffusion. Overall, this unmodified hierarchically porous silica powder from DPS shows great promise for the selective extraction of Sc from various feedstocks.

DOI： 10.1021/acssuschemeng.3c04672

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PubMed

Dedicated to Professor Sumio Sakka, Founding Editor of Journal of Sol-Gel Science and Technology Reviewed

Nakanishi, K; Kozuka, H

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 104 ( 3 ) page： 447 - 448 2022.12

Porous polymer-derived ceramics: Flexible morphological and compositional controls through sol-gel chemistry Reviewed

George Hasegawa, Kazuyoshi Kanamori, Kazuki Nakanishi

JOURNAL OF THE AMERICAN CERAMIC SOCIETY Vol. 105 ( 1 ) page： 5 - 34 2022.1

Language：English Publishing type：Research paper (scientific journal) Publisher：WILEY

Porous nonoxide ceramics have exhibited impressive progress in terms of synthesis and applications over the past few decades because of their unique characteristics distinguished from the oxide counterparts. From the synthetic aspect, the preceramic polymer route, where nonoxide ceramics such as carbides and nitrides are produced from molecular precursors, offers exceptional opportunities to elaborate and control the material shape as well as the micro- and nanostructures in concert with various techniques. This review presents monolithic ceramic materials based on various reduced phases bearing hierarchical porosity with a focus on those obtained from macroporous preceramic monoliths prepared via the one-pot sol-gel process accompanied by spinodal decomposition. Here, we highlight two classes of preceramic inorganic-organic hybrid gels: organometallic crosslinked polymers based on poly(silsesquioxane)s and nonorganometallic hybrid networks related to Ti without Ti-C bonds. The polymer-to-ceramic conversion processes are discussed with concern for the crystal transition behaviors and the variation of pore properties in different length scales upon heating. In addition, although out of the preceramic polymer category, some examples of inorganic-organic nanocomposite gels with a carbonizable polymer and/or urea for yielding porous metal carbides and nitrides in a monolithic form are introduced as well, which provides extended versatility toward a variety of transition metal systems.

DOI： 10.1111/jace.18130

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Synthesis of Hierarchically Porous Metal Oxide Monoliths <i>via</i> Sol-Gel Process Accompanied by Phase Separation From Divalent Metal Salts: A Short Review Reviewed

Lu, XM; Nakanishi, K

FRONTIERS IN CHEMICAL ENGINEERING Vol. 3 2021.12

Language：English Publishing type：Research paper (scientific journal) Publisher：Frontiers in Chemical Engineering

The sol–gel process accompanied by phase separation is one of the methods to prepare hierarchically porous monoliths, hierarchically porous monolith, which is applicable not only to oxides but also to various materials compositions such as metal phosphates, organic-polymers/carbons, metal-organic frameworks. It is not until recently, however, that progress has been made in the preparation of low-valence metal oxide HPMs, such as those of magnesium, manganese, cobalt, nickel, etc. Due to the difficulty of divalent metal precursors to form homogeneous gels, different approaches from those established for trivalent and tetravalent counterparts have been attempted. This short review introduces the methods and trials in the preparation of metal oxide HPMs from divalent metal salts.

DOI： 10.3389/fceng.2021.787788

Web of Science

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Variation of meso- and macroporous morphologies in resorcinol-formaldehyde (RF) gels tailored via a sol-gel process combined with soft-templating and phase separation Reviewed

George Hasegawa, Takaya Yano, Hirofumi Akamatsu, Katsuro Hayashi, Kazuki Nakanishi

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY Vol. 95 ( 3 ) page： 801 - 812 2020.9

Language：English Publishing type：Research paper (scientific journal) Publisher：SPRINGER

A wide-range control over multimodal pore systems in porous monoliths is a key technology for developing functional materials, as the favorable pore structures in different length scales are required to be tailored depending on their application fields. In the alkoxy-derived sol-gel systems of silica and organosilicates, the synthetic methodology of meso- and macroporous monoliths with tunable pore properties has been developed by combining the supramolecular self-assembly of a Pluronic surfactant and polymerization-induced phase-separation techniques. This strategy has been applied to the sol-gel process of phenolic resins, giving rise to the hierarchically porous polymer gels with ordered mesoporosity and the corresponding carbon monoliths after carbonization. However, the controllable size range has been limited so far. This study has explored the relationship between the starting composition and the bimodal pore properties in further detail aiming at a better control of pore properties in phenolic resins. The enlargement of mesopore size has been achieved, yet associated with broadening the mesopore size distribution and coarsening the macropore morphology, resulting in the particle aggregates. The systematical investigation also reveals that the addition of KCl can improve the micelle arrangement in macroframework and provide the narrower mesopore size distribution.

DOI： 10.1007/s10971-020-05236-9

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Self‐Assembly of Metal–Organic Frameworks into Monolithic Materials with Highly Controlled Trimodal Pore Structures Reviewed

Yosuke Hara, Kazuyoshi Kanamori, Kazuki Nakanishi

Angewandte Chemie Vol. 131 ( 52 ) page： 19223 - 19229 2019.12

Thermogravimetric Evolved Gas Analysis and Microscopic Elemental Mapping of the Solid Electrolyte Interphase on Silicon Incorporated in Free-Standing Porous Carbon Electrodes Reviewed

Hasegawa, G; Kanamori, K; Nakanishi, K; Hayashi, K

LANGMUIR Vol. 35 ( 39 ) page： 12680 - 12688 2019.10

Language：English Publishing type：Research paper (scientific journal) Publisher：Langmuir

Free-standing electrodes, which are free from additives (binders and conductive agents) and even current collectors, are useful in terms of both application research and fundamental study. Here, we demonstrate the preparation of binder-free monolithic carbon electrodes embracing Si nanoparticles in their well-defined porous scaffolds via the one-pot sol-gel reaction followed by carbonization. The free-standing electrodes with a thickness of 150 μm work out as a high-areal-density anode for Li-ion batteries, delivering up to ca. 7 mA h cm-2. As the Si content increases, the capacity decay on cycling becomes pronounced, which is likely to associate with the fracturing and pulverization of Si nanoparticles even with the size smaller than 100 nm after long-term cycles. The thermogravimetry-mass spectrometry profile of the cycled electrode corroborates the successive electrolyte decomposition to grow solid electrolyte interphase (SEI) mainly composed of lithium alkylcarbonates, polymeric species, and LiF, rendering the electrode mass nearly double of its original state after 200 cycles. The elemental mapping analysis reveals that LiF is generated inhomogeneously in the monolithic electrodes unlike the other SEI components, resulting in the concentration gradient depending on the distance from a Li counter electrode.

DOI： 10.1021/acs.langmuir.9b02085

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Superflexible Multifunctional Polyvinylpolydimethylsiloxane-Based Aerogels as Efficient Absorbents, Thermal Superinsulators, and Strain Sensors Reviewed

Zu, Guoqing, Kanamori, Kazuyoshi, Maeno, Ayaka, Kaji, Hironori, Nakanishi, Kazuki

Angewandte Chemie-International Edition Vol. 57 ( 31 ) page： 9722 - 9727 2018.7

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley

Aerogels are porous materials but show poor mechanical properties and limited functionality, which significantly restrict their practical applications. Preparation of highly bendable and processable aerogels with multifunctionality remains a challenge. Herein we report unprecedented superflexible aerogels based on polyvinylpolydimethylsiloxane (PVPDMS) networks, PVPDMS/polyvinylpolymethylsiloxane (PVPMS) copolymer networks, and PVPDMS/PVPMS/graphene nanocomposites by a facile radical polymerization/hydrolytic polycondensation strategy and ambient pressure drying or freeze drying. The aerogels have a doubly cross-linked organic-inorganic network structure consisting of flexible polydimethylsiloxanes and hydrocarbon chains with tunable cross-linking density, tunable pore size and bulk density. They have a high hydrophobicity and superflexibility and combine selective absorption, efficient separation of oil and water, thermal superinsulation, and strain sensing.

DOI： 10.1002/anie.201804559

Superflexible Multifunctional Polyvinylpolydimethylsiloxane‐Based Aerogels as Efficient Absorbents, Thermal Superinsulators, and Strain Sensors Reviewed

Guoqing Zu, Kazuyoshi Kanamori, Ayaka Maeno, Hironori Kaji, Kazuki Nakanishi

Angewandte Chemie Vol. 130 ( 31 ) page： 9870 - 9875 2018.7

Dynamic spring-back behavior in evaporative drying of polymethylsilsesquioxane monolithic gels for low-density transparent thermal superinsulators Reviewed

Hayase, Gen, Kanamori, Kazuyoshi, Maeno, Ayaka, Kaji, Hironori, Nakanishi, Kazuki

Journal of Non-Crystalline Solids Vol. 434 page： 115 - 119 2016.2

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER SCIENCE BV

Ambient pressure drying of polymethylsilsesquioxane gels via dynamic shrinkage-reexpansion has been investigated for preparation of aerogel-like xerogels and their application to thermal superinsulators. An extended aging of wet gels in aqueous solution containing precursor-derived species is found to be crucial in obtaining crack-free, monolithic xerogels with sufficiently low thermal conductivity (13.7 mW m(-1) K-1) at bulk density of 0.140 g cm(-3) (porosity similar to 90%). (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jnoncrysol.2015.12.016

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Surface Functionalization of Silica by Si-H Activation of Hydrosilanes Reviewed

Nirmalya Moitra, Shun Ichii, Toshiyuki Kamei, Kazuyoshi Kanamori, Yang Zhu, Kazuyuki Takeda, Kazuki Nakanishi, Toyoshi Shimada

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 136 ( 33 ) page： 11570 - 11573 2014.8

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Inspired by homogeneous borane catalysts that promote Si-H bond activation, we herein describe an innovative method for surface modification of silica using hydrosilanes as the modification precursor and tris(pentafluorophenyl)borane (B(C6F5)(3)) as the catalyst. Since the surface modification reaction between surface silanol and hydrosilane is dehydrogenative, progress and termination of the reaction can easily be confirmed by the naked eye. This new metal-free process can be performed at room temperature and requires less than 5 min to complete. Hydrosilanes bearing a range of functional groups, including alcohols and carboxylic acids, have been immobilized by this method. An excellent preservation of delicate functional groups, which are otherwise decomposed in other methods, makes this methodology appealing for versatile applications.

DOI： 10.1021/ja504115d

Other Link： http://orcid.org/0000-0002-8069-4780

A Superamphiphobic Macroporous Silicone Monolith with Marshmallow-like Flexibility Reviewed

Gen Hayase, Kazuyoshi Kanamori, George Hasegawa, Ayaka Maeno, Hironori Kaji, Kazuki Nakanishi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 52 ( 41 ) page： 10788 - 10791 2013.10

Facile Synthesis of Marshmallow-like Macroporous Gels Usable under Harsh Conditions for the Separation of Oil and Water Reviewed

Gen Hayase, Kazuyoshi Kanamori, Masashi Fukuchi, Hironori Kaji, Kazuki Nakanishi

ANGEWANDTE CHEMIE-INTERNATIONAL EDITION Vol. 52 ( 7 ) page： 1986 - 1989 2013

Hierarchically Porous Monoliths of Oxygen-deficient Anatase TiO<sub>2-x</sub> with Electronic Conductivity (vol 3, pg 7205, 2013) Reviewed

Kitada, A; Hasegawa, G; Kobayashi, Y; Miyazaki, K; Abe, T; Kanamori, K; Nakanishi, K; Kageyama, H

RSC ADVANCES Vol. 3 ( 48 ) page： 26475 - 26475 2013

Selective Preparation of Macroporous Monoliths of Conductive Titanium Oxides TinO2n-1 (n=2, 3, 4, 6) Reviewed

Atsushi Kitada, George Hasegawa, Yoji Kobayashi, Kazuyoshi Kanamori, Kazuki Nakanishi, Hiroshi Kageyama

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Vol. 134 ( 26 ) page： 10894 - 10898 2012.7

Language：English Publishing type：Research paper (scientific journal) Publisher：AMER CHEMICAL SOC

Monolithic conductive titanium oxides TinO2n-1 (n = 2, 3, 4, 6) with well-defined macropores have been successfully prepared as a single phase, via reduction of a macroporous TiO2 precursor monolith using zirconium getter. Despite substantial removal of oxide ions, all the reduced monoliths retain the macropore properties of the precursor, i.e., uniform pore size distribution and pore volume. Furthermore, compared to commercial porous Ebonex (shaped conductive TinO2n-1), the bulk densities (1.8 g cm(-3)) are half, and the porosities (60%) are about 3 times higher. The obtained TinO2n-1 (n = 2, 3, 4, 6) macroporous monoliths could find applications as electrodes for many electrochemical reactions.

DOI： 10.1021/ja302083n

Hierarchically Porous Materials by Phase Separation: Monoliths Reviewed

Nakanishi, K

HIERARCHICALLY STRUCTURED POROUS MATERIALS: FROM NANOSCIENCE TO CATALYSIS, SEPARATION, OPTICS, ENERGY, AND LIFE SCIENCE page： 241 - 267 2012

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<NAKANISHI Kazuki>

Papers - NAKANISHI Kazuki