Details of a Researcher - YABUUCHI Naoaki

Papers - YABUUCHI Naoaki

about 110

Mechanistic study on moisture exposure of Ti-based layered oxides for sodium storage applications

Campéon, BDL; Ishikawa, T; Tomohiro, K; Yabuuchi, N

JOURNAL OF MATERIALS CHEMISTRY A 13 ( 3 ) 2187 - 2197 2025.1 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Efficient Pathways to Improve Electrode Performance of P’2 Na2/3MnO2 for Sodium Batteries

Ugata Yosuke, Kuriyama Tomohiro, Yabuuchi Naoaki

Chemical Communications Early Access 2024.11 [Reviewed]

DOI CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：The Royal Society of Chemistry Joint Work

A Mn-based sodium-containing layered oxide, P'2-type Na2/3MnO2, is revisited as a positive electrode material for sodium-ion batteries, and factors affecting its electrochemical performances are examined. The cyclability of Na2/3MnO2 is remarkably improved by increasing the lower cut-off voltage during cycling even though the reversible capacity is sacrificed. Furthermore, the use of highly concentrated electrolytes, in which the presence of free solvent molecules is eliminated, effectively suppresses the dissolution of Mn ions, thus enabling stable cycling with >85% capacity retention for continuous 300 cycles.

MXene Electrodes for All Strain-Free Solid-State Batteries

Kawai, K; Lee, H; Nomura, Y; Fujita, M; Kitaura, H; Hosono, E; Nakajima, H; Tsukasaki, H; Mori, S; … Show more authors

ACS APPLIED MATERIALS & INTERFACES 16 ( 42 ) 57377 - 57385 2024.10

DOI Web of Science PubMed

Language：English Publishing type：Research paper (scientific journal) Joint Work

A Practical and Sustainable Ni/Co-Free High-Energy Electrode Material: Nanostructured LiMnO2

Miyaoka Yuka, Sato Takahito, Oguro Yuna, Kondo Sayaka, Nakano Koki, Nakayama Masanobu, Ugata Yosuke … Show more authors

ACS Central Science 10 ( 9 ) 1718 - 1732 2024.9

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society (ACS) Joint Work

Ni/Co-free high-energy positive electrode materials are of great importance to ensure the sustainability of Li-ion battery production and its supply chain in addition to minimizing environmental impact. Here, nanostructured LiMnO2 with both orthorhombic/monoclinic layered domains is synthesized, and its lithium storage properties and mechanism are examined. High-energy mechanical milling is used to convert the metastable and nanosized LiMnO2 adopting the cation-disordered rocksalt structure to an optimal domain-segregated layered LiMnO2. This positive electrode produces an energy density of 820 W h kg–1, achieved by harnessing a large reversible capacity with relatively small voltage hysteresis on electrochemical cycles. Moreover, voltage decay for cycling, as observed for Li-excess Mn-based electrode materials, is effectively mitigated. Furthermore, by determining the structure–property relationships of different LiMnO2 polymorphs, LiMnO2 with similar domain structure and surface area is successfully synthesized with an alternative and simpler method, without the metastable precursor and high-energy mechanical milling. The cyclability of domain-containing LiMnO2 is also improved with the use of a highly concentrated electrolyte coupled with a lithium phosphate coating due to the suppression of Mn dissolution. These findings maximize the possibility of the development of high-energy, low-cost, and practical rechargeable batteries made from sustainable and abundant Mn sources without Ni/Co.

Influence of Aluminum Substitution on Anionic Redox Activation and Stabilization in P′2-Type Na2/3MnO2 for Na/Li Battery Applications

Yin Jiaxuan, Zhang Yanjia, Kuriyama Tomohiro, Jin Yongcheng, Yabuuchi Naoaki

Chemistry of Materials 36 ( 18 ) 8682 - 8691 2024.9

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society Joint Work

Lithium-ion batteries are now successfully developed with higher energy densities than classical aqueous-based battery technologies and are used as power sources for electric vehicles and other electric storage applications. Sodium-ion batteries are another emerging battery technology, but their energy density is not high compared to that of their Li counterparts. Anionic redox reactions have attracted attention due to their potential to enhance the reversible capacity and operating voltage of positive electrode materials in Na/Li batteries. To understand the influence of Al substitution on the activation mechanism of anionic redox reactions in Na-/Li-containing Mn-based layered oxides, the P2-type Al-substituted Na2/3Al0.1Mn0.9O2 is designed to explore the difference in the anionic redox behavior. LiyAl0.1Mn0.9O2 is also prepared by electrochemical ion exchange, and the anionic redox behavior was compared for both samples. The Al-substituted Na2/3Al0.1Mn0.9O2 provides better cycling performance with partial activation of anionic redox, which is not observed for P′2-type Na2/3MnO2. Good reversibility for Na2/3Al0.1Mn0.9O2 and LiyAl0.1Mn0.9O2 with anionic redox is achieved, and this improvement originates from the nonexcessive use of anionic redox in electrode materials. This finding opens the possibility to develop high-energy sodium/lithium insertion materials with reversible anionic redox.

Unlocking Electrode Performance of Disordered Rocksalt Oxides Through Structural Defect Engineering and Surface Stabilization with Concentrated Electrolyte

Zhang Yanjia, Ugata Yosuke, Campeon BenoitDenis Louis, Yabuuchi Naoaki

Advanced Energy Materials 14 ( 23 ) 2024.6

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag GmbH Joint Work

Li-excess cation-disordered rocksalt oxides can boost the energy density of rechargeable batteries by using anionic redox, but the inferior reversibility of anionic redox hinders its use for practical applications. Herein, a binary system of Li3NbO4-LiMnO2 is targeted and the systematic study on factors affecting electrode reversibility, i.e., percolation probability, electronic conductivity, defect concentrations, and electrolyte solutions, is conducted. A Mn-rich sample, Li1.1Nb0.1Mn0.8O2, delivers a smaller reversible capacity compared with a Li-rich sample, Li1.3Nb0.3Mn0.4O2, because of the limitation of ionic migration associated with insufficient percolation probability for disordered oxides. Nevertheless, a larger reversible capacity of Li1.3Nb0.3Mn0.4O2 originates from excessive activation of anionic redox, leading to the degradation of electrode reversibility. The superior performance of Li1.1Nb0.1Mn0.8O2, including Li ion migration kinetics and electronic transport properties, is unlocked by the enrichment of structural defects for nanosized oxides. Moreover, electrode reversibility is further improved by using a highly concentrated electrolyte solution with LiN(SO2F)(2) through the surface stabilization on high-voltage exposure. Superior capacity retention, >100 cycles, is achieved for nanosized Li1.1Nb0.1Mn0.8O2. The electrolyte decomposition and surface stabilization mechanisms are also carefully examined, and it is revealed that the use of highly concentrated electrolyte solution can effectively prevent lattice oxygen being further oxidized and transition metal ion dissolution.

State-of-the-art solid-state electrochemistry in Japan

Yabuuchi, N

JOURNAL OF SOLID STATE ELECTROCHEMISTRY 28 ( 12 ) 4353 - 4353 2024.6

DOI Web of Science

Language：Japanese Publishing type：Research paper (scientific journal) Joint Work

A methodology to synthesize easily oxidized materials containing Li ions in an inert atmosphere

Konuma Itsuki, Ugata Yosuke, Yabuuchi Naoaki

Energy Advances 3 ( 5 ) 962 - 967 2024.5

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：The Royal Society of Chemistry Joint Work

A series of lithium-containing oxides with V3+ and Mn3+ ions are proposed as emerging high-capacity positive electrode materials for lithium-ion batteries. These oxides are typically synthesized by a calcination process in an inert atmosphere. For the successful synthesis of these materials, the strict control of oxygen partial pressure is necessary to prevent partial oxidation of materials during calcination. In this article, a simple methodology used in laboratory-scale material production, i.e., an oxygen trap by Cu foil, is described to synthesize phase pure oxides, which are easily oxidized on calcination. To demonstrate the benefit of the methodology, Li8/7Ti2/7V4/7O2 and Li8/7Ti2/7Mn4/7O2 are selected as lithium-containing oxides with V3+ and Mn3+ ions, respectively. Single phase oxides are successfully obtained from the pellets calcined with Cu foil, whereas partially oxidized phases are obtained for the pellets calcined without Cu foil. Moreover, phase-pure oxides synthesized with Cu foil show much better performance as positive electrode materials for battery applications. This methodology is also expected to be applied for material synthesis for diverse applications. A simple methodology to synthesize easily oxidized materials with Mn3+ and V3+ ions, which are used as emerging high-capacity positive electrode materials for lithium-ion batteries, is proposed.

Unlocking Electrode Performance of Disordered Rocksalt Oxides Through Structural Defect Engineering and Surface Stabilization with Concentrated Electrolyte

Zhang, YJ; Ugata, Y; Campéon, BL; Yabuuchi, N

ADVANCED ENERGY MATERIALS 14 ( 23 ) 2024.4 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Fundamental methods of electrochemical characterization of Li insertion materials for battery researchers

Ugata Yosuke, Motoki Chihaya, Dokko Kaoru, Yabuuchi Naoaki

Journal of Solid State Electrochemistry 28 ( 3-4 ) 1387 - 1401 2024.3

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Joint Work

Li-ion batteries have gained intensive attention as a key technology for realizing a sustainable society without dependence on fossil fuels. To further increase the versatility of Li-ion batteries, considerable research efforts have been devoted to developing a new class of Li insertion materials, which can reversibly store Li-ions in host structures and are used for positive/negative electrode materials of Li-ion batteries. Appropriate evaluations of electrochemical properties of Li insertion materials are essential for the research of electrode materials in laboratory. In this article, we describe fundamental methods of electrochemical characterization of Li insertion materials including electrode preparation, cell assembly, and electrochemical measurement in the laboratory-scale research. The importance of selection for battery components such as electrolyte solutions, polymer binders, separators, and current collectors on the electrochemical properties of Li insertion materials, is also discussed. This article offers basic knowledge and techniques for electrochemical characterizations of Li insertion materials to students and beginners for battery research.

Unified understanding and mitigation of detrimental phase transition in cobalt-free LiNiO2

Konuma Itsuki, Ikeda Naohiro, Campeon Benoit D. L., Fujimura Hinata, Kikkawa Jun, Luong Huu Duc, Ta … Show more authors

Energy Storage Materials 66 103200 2024.2

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Joint Work

Ni-enriched layered materials are used as electrode materials of Li -ion batteries for electric vehicle applications. Stoichiometric LiNiO2 with cationic Ni3+/Ni4+ redox is the ideal electrode material, but the gradual loss of capacity at the high voltage region, associated with Ni ion migration, hinders its use for practical applications. Therefore, to improve electrode reversibility of LiNiO2, less abundant Co ions and/or other electrochemically inactive ions, e.g., Al3+ ions, are in part substituted for Ni ions. Nevertheless, a unified understanding of improvement by metal substitution is as yet not established. In this study, the origin causing detrimental phase transition in LiNiO2 is discussed through the detailed analysis on LiNiO2 integrated with nanosized Li3PO4 derived from a metastable and rocksalt LiNiO2-Li3PO4 solid solution sample. LiNiO2 derived from the metastable rocksalt oxide has approximately 6 % anti -site defects, and the particle size growth is suppressed by uniformly dispersed nanosized Li3PO4. In low crystallinity LiNiO2 with partial structural disordering, the Ni ion migration to tetrahedral sites is effectively suppressed because of repulsive electrostatic interaction from Ni ions in Li layers. Moreover, from these findings, non-stoichiometric Li0.975Ni1.025O2 with smaller particle size has been directly synthesized without high-energy milling and Li3PO4 integration, and significant improvement of electrode reversibility is achieved. Electrode reversibility of non-stoichiometric Li0.975Ni1.025O2 is further improved through surface stabilization in a highly concentrated electrolyte solution. The unified understanding of deterioration mechanisms for LiNiO2 offers a new criterion to design Co -free LiNiO2 without metal substitution, leading to full utilization of a reversible capacity for layered materials.

Virtues of Cold Isostatic Pressing for Preparation of All-Solid-State-Batteries with Poly(Ethylene Oxide)

Campeon Benoit D. L., Rajendra Hongahally B., Yabuuchi Naoaki

ChemSusChem 17 ( 3 ) 2024.2

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Verlag GmbH Joint Work

All-solid-state-batteries (ASSBs) necessitate the preparation of a solid electrolyte and an electrode couple with individually dense and compact structures with superior interfacial contact to minimize overall cell resistance. A conventional preparation method of solid polymer electrolyte (SPE) with polyethylene-oxide (PEO) generally consists in employing uni-axial hot press (HP) to densify SPE. However, while uni-axial press with moderate pressure effectively densifies PEO with Li salts, excessive pressure also unavoidably results in perpendicular elongation and deformation for polymer matrix. In this research, to overcome this limitation for the uni-axial press technique, a cold isostatic press (CIP) is applied to the fabrication of ASSB with PEO and LiFePO4. CIP effectively and uniformly applies pressure as high as 500 MPa without deformation. Characterizations confirm that CIP treated SPE has enhanced mechanical puncture strength, increasing from 499.3 +/- 22.6 to 539.3 +/- 22.6 g, and ionic conductivity, increasing from 1.04x10-4 to 1.91x10-4 S cm-1 at 50 degrees C. ASSB treated by CIP demonstrates remarkably enhanced rate capability and cyclability compared with the cell processed by HP, which is further evidenced by improvement of the apparent Li ion diffusion constant based on Sand equation analysis. The improvement enabled by CIP treatment originates from the superior interface uniformity between electrodes and SPE and from the densification of the LiFePO4 and SPE composite electrode. The effect of cold isostatic press (CIP) on solid polymer electrolyte (SPEs)-based all-solid-state batteries (ASSBs) is reported in this work. CIP treatment improves SPE's mechanical strength and ionic conductivity. The resulting ASSBs demonstrates enhanced rate capability, cyclability, and Li ion diffusion, attributed to interface uniformity and electrode densification achieved through CIP treatment.+image

Efficient Surface Passivation of Ti-Based Layered Materials by a Nonfluorine Branched Copolymer for Durable and High-Power Sodium-Ion Batteries

Campéon, BDL; Umezawa, R; Pandey, AK; Ishikawa, T; Tsuchiya, Y; Ishigaki, Y; Kanto, R; Yabuuchi, N

ACS APPLIED MATERIALS & INTERFACES 16 ( 3 ) 3396 - 3405 2024.1 [Reviewed]

DOI Web of Science PubMed

Language：English Publishing type：Research paper (scientific journal) Joint Work

正極材料の未来展望

藪内直明

関西電気化学テキストシリーズ 2023.2 ( 0 ) 02009 - 02009 2023.10

DOI CiNii Research

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：公益社団法人電気化学会関西支部 Single Work

電気自動車用リチウムイオン蓄電池の正極材料としてニッケルリッチの材料が利用されているが，リチウムイオン電池のさらなるエネルギー密度の向上には正極材料の進化が不可欠である．本発表では，高性能ニッケル系層状材料，高エネルギー密度・低コストマンガン系材料，全固体電池用のバナジウム系材料などの研究成果について，これら材料の電池特性に加え，材料合成手法や充放電反応機構について紹介し，電池特性劣化機構の詳細解析とその抑制の実現可能性について議論を行う．

New functionality of electrode materials with highly concentrated electrolytes

Yosuke Ugata, Naoaki Yabuuchi

Trends in Chemistry 5 ( 9 ) 672 - 683 2023.9 [Reviewed]

DOI Web of Science CiNii Research

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Cell Press Joint Work

The use of Li-excess metal oxides as positive electrodes coupled with metallic Li-negative electrodes is regarded as a promising route toward achieving higher energy density for Li-ion batteries. However, the reversibility and cycle life of these electrode materials in conventional carbonate-based electrolyte solutions containing lithium salts at about 1 mol dm-3 often are still not an acceptable level for practical applications. Recently, as an important trend for electrolyte design, highly concentrated electrolytes (HCEs) have received much attention owing to new and emerging functionality through their superior compatibility with these advanced electrode materials. These new functionalities of electrode materials coupled with the use of HCEs and their mechanistic insights are reviewed.

Durable Manganese-Based Li-Excess Electrode Material without Voltage Decay: Metastable and Nanosized Li2MnO1.5F1.5

8 ( 6 ) 2753 - 2761 2023.6

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Joint Work

Anion-Induced Interfacial Liquid Layers on LiCoO2 in Salt-in-Water Lithium-Ion Batteries

Oh Hyunjeong, Shin Seung-Jae, Choi Eunjin, Yamagishi Hirona, Ohta Toshiaki, Yabuuchi Naoaki, Jung H … Show more authors

JACS Au 3 ( 5 ) 1392 - 1402 2023.5

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society Joint Work

The incompatibility of lithium intercalation electrodes with water has impeded the development of aqueous Li-ion batteries. The key challenge is protons which are generated by water dissociation and deform the electrode structures through intercalation. Distinct from previous approaches utilizing large amounts of electrolyte salts or artificial solid-protective films, we developed liquid-phase protective layers on LiCoO2 (LCO) using a moderate concentration of 0.5 similar to 3 mol kg-1 lithium sulfate. Sulfate ion strengthened the hydrogen-bond network and easily formed ion pairs with Li+, showing strong kosmotropic and hard base characteristics. Our quantum mechanics/molecular mechanics (QM/MM) simulations revealed that sulfate ion paired with Li+ helped stabilize the LCO surface and reduced the density of free water in the interface region below the point of zero charge (PZC) potential. In addition, in situ electrochemical surface-enhanced infrared absorption spectroscopy (SEIRAS) proved the appearance of inner-sphere sulfate complexes above the PZC potential, serving as the protective layers of LCO. The role of anions in stabilizing LCO was correlated with kosmotropic strength (sulfate > nitrate > perchlorate > bistriflimide (TFSI-)) and explained better galvanostatic cyclability in LCO cells.

Nonflammable Fluorinated Ester-Based Electrolytes for Safe and High-Energy Batteries with LiCoO2

35 ( 9 ) 3686 - 3693 2023.5

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Joint Work

Anion-Induced Interfacial Liquid Layers on LiCoO2 in Salt-in-Water Lithium-Ion Batteries

Oh Hyunjeong, Shin Seung-Jae, Choi Eunjin, Yamagishi Hirona, Ohta Toshiaki, Yabuuchi Naoaki, Jung H … Show more authors

JACS AU 3 ( 5 ) 1392 - 1402 2023.4 [Reviewed]

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Language：English Publishing type：Research paper (scientific journal) Joint Work

Improved reversibility of lithium deposition and stripping with high areal capacity under practical conditions through enhanced wettability of the polyolefin separator to highly concentrated electrolytes

Ugata Yosuke, Motoki Chihaya, Nishikawa Satoshi, Yabuuchi Naoaki

Energy Advances 2 ( 4 ) 503 - 507 2023.4

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：The Royal Society of Chemistry Joint Work

Highly concentrated electrolytes (HCEs) have attracted great interest as electrolyte candidates for Li metal batteries because of their functionalities in improving the reversibility and cycling performance of the Li metal negative electrode. However, the poor wettability of conventional polyolefin separators toward HCEs with high viscosity remains a critical issue to be addressed. Although porous glass fiber filters are often used as separators for HCEs, Li dendrites easily penetrate the separator during repeated Li deposition/stripping under practical conditions, leading to an internal short circuit. Here, we report that the use of a meta-aramid-coated polyolefin separator improves the wettability with HCEs owing to its polar surface functional groups and enables stable and dendrite-free Li deposition/stripping with high coulombic efficiency of similar to 98% at practical areal capacity (2 mA h cm-2) for 100 cycles. A combined strategy utilizing HCEs and functional separators provides a promising possibility for the development of practical Li metal batteries. Highly concentrated electrolytes (HCEs) have attracted great interest as electrolyte candidates for Li metal batteries because of their functionalities in improving the reversibility and cycling performance of the Li metal negative electrode.

Improved Electrode Reversibility of Nanosized Li1.15Nb0.15Mn0.7O2 through Li3PO4 Integration

Electrochemistry 91 ( 3 ) 037004 2023.3 [Reviewed]

DOI CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：The Electrochemical Society of Japan Joint Work

Improved electrode reversibility of anionic redox with highly concentrated electrolyte solution and aramid-coated polyolefin separator

Nanaka Shimada, Yosuke Ugata, Satoshi Nishikawa, Daisuke Shibata, Toshiaki Ohta, Naoaki Yabuuchi

Energy Advances 2 ( 4 ) 508 - 512 2023.3 [Reviewed]

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Single Work

Partially Reversible Anionic Redox for Lithium-Excess Cobalt Oxides with Cation-Disordered Rocksalt Structure

Zhang Yanjia, Sawamura Miho, Harada Maho, Noda Yusuke, Nakayama Masanobu, Goto Masato, Kan Daisuke, … Show more authors

Journal of Physical Chemistry C 127 ( 5 ) 2194 - 2203 2023.2

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society Joint Work

Li-excess electrode materials potentially boost the energy density of Li-ion batteries, but the origin of the instability of anionic redox in cation-disordered rocksalt material is still under debate. In this study, a binary system of Li3NbO4-CoO is targeted as electrode materials for lithium storage applications. In this binary system, stoichiometric LiCo2/3Nb1/3O2 crystallizes into a rocksalt-type structure with partial ordering of Nb ions. Upon increase of the Li3NbO4 fraction, cation ordering is lost, forming a cation-disordered rocksalt structure in Li-excess phases. Although Li-excess Li4/3Co2/9Nb4/9O2 delivers a large reversible capacity as electrode materials, inferior cyclability and large voltage hysteresis for charge/discharge curves are noted. Irreversible structural changes in electrochemical cycles are also evidenced from results of in situ XRD measurements, suggesting that anionic redox is destabilized for Li4/3Co2/9Nb4/9O2. X-ray absorption spectroscopy reveals that partial stabilization of ligand holes as observed in SrCoO3 is achieved for these oxides. Ligand holes are more effectively stabilized for Li7/6Co4/9Nb7/18O2 with less Li-excess and Co-rich composition. Through systematic study of the binary system of Li3NbO4-CoO with different chemical compositions, factors affecting reversibility and irreversibility of anionic redox are further discussed.

Nanoscale domain imaging of Li-rich disordered rocksalt-type cathode materials with X-ray spectroscopic ptychography

25 ( 5 ) 3867 - 3874 2023.2 [Reviewed]

DOI Web of Science PubMed CiNii Research

Language：English Publishing type：Research paper (scientific journal) Joint Work

Partially Reversible Anionic Redox for Lithium-Excess Cobalt Oxides with Cation-Disordered Rocksalt Structure

Yanjia Zhang, Miho Sawamura, Maho Harada, Yusuke Noda, Masanobu Nakayama, Masato Goto, Daisuke Kan, … Show more authors

The Journal of Physical Chemistry C 127 ( 5 ) 2194 - 2203 2023.1 [Reviewed]

DOI Web of Science

Authorship：Corresponding author Language：English Publishing type：Research paper (scientific journal) Single Work

P3-type layered K0.6Cr0.6Ti0.4O2 for potassium storage applications

Pandey Alok K., Campeon Benoit D. L., Konuma Itsuki, Yabuuchi Naoaki

Energy Advances 2 ( 1 ) 98 - 102 2023.1

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：The Royal Society of Chemistry Joint Work

P3-type K0.6Cr0.6Ti0.4O2 is synthesized via a solid-state method and is tested as a positive electrode for potassium-ion batteries. It operates at a higher potential of E-ave. = 3.14 V vs. K/K+, while delivering a reversible capacity superior to 40 mA h g(-1) in a K cell. Excellent reversibility as an electrode material is achieved with a 3.9 V cutoff based on solid-state redox reaction of Cr ions. An in situ X-ray diffraction study reveals a reversible phase transition during K+ ion extraction/insertion. Furthermore, the excellent cyclability for 500 cycles at a rate of 40 mA g(-1) coupled with good rate capability demonstrates its advantage as the host structure for potassium ion storage applications.

A near dimensionally invariable high-capacity positive electrode material

Itsuki Konuma, Damian Goonetilleke, Neeraj Sharma, Takuhiro Miyuki, Satoshi Hiroi, Koji Ohara, Yuki … Show more authors

Nature Materials 22 ( 2 ) 225 - 234 2022.12 [Reviewed]

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Language：English Publishing type：Research paper (scientific journal) Single Work

Extended conjugated carbonyl-containing polymer as a negative electrode material for Na-ion batteries

Sugawara Kazuki, Yabuuchi Naoaki, Miyasaka Makoto

POLYMER JOURNAL 54 ( 9 ) 1111 - 1118 2022.9 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Unexpectedly Large Contribution of Oxygen to Charge Compensation Triggered by Structural Disordering: Detailed Experimental and Theoretical Study on a Li₃NbO₄–NiO Binary System

福間隆太朗, 原田真帆, 趙文文, 澤村美穂, 野田祐輔, 中山将伸, 後藤真人, 菅大介, 島川祐一, 米村雅雄, 池田直宏, 綿貫竜太, 福山小百合, 韓貞姫, 福満 … Show more authors

ACS Central Science 8 ( 6 ) 775 - 794 2022.6 [Reviewed]

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：American Chemical Society (ACS) Joint Work

Dependence on lithium-ion batteries for automobile applications is rapidly increasing. The emerging use of anionic redox can boost the energy density of batteries, but the fundamental origin of anionic redox is still under debate. Moreover, to realize anionic redox, many reported electrode materials rely on manganese ions through π-type interactions with oxygen. Here, through a systematic experimental and theoretical study on a binary system of Li₃NbO₄–NiO, we demonstrate for the first time the unexpectedly large contribution of oxygen to charge compensation for electrochemical oxidation in Ni-based materials. In general, for Ni-based materials, e.g., LiNiO₂, charge compensation is achieved mainly by Ni oxidation, with a lower contribution from oxygen. In contrast, for Li₃NbO₄–NiO, oxygen-based charge compensation is triggered by structural disordering and σ-type interactions with nickel ions, which are associated with a unique environment for oxygen, i.e., a linear Ni–O–Ni configuration in the disordered system. Reversible anionic redox with a small hysteretic behavior was achieved for LiNi₂/₃Nb₁/₃O₂ with a cation-disordered Li/Ni arrangement. Further Li enrichment in the structure destabilizes anionic redox and leads to irreversible oxygen loss due to the disappearance of the linear Ni–O–Ni configuration and the formation of unstable Ni ions with high oxidation states. On the basis of these results, we discuss the possibility of using σ-type interactions for anionic redox to design advanced electrode materials for high-energy lithium-ion batteries.

Metastable and Nanosized Li1.2Nb0.2V0.6O2 for High-Energy Li-ion Batteries

QI Ruijie, CAMPÉON Benoît D. L., KONUMA Itsuki, SATO Yoshihiko, KANEDA Yuko, KONDO Masashi, YABUUCH … Show more authors

Electrochemistry 90 ( 3 ) 037005 - 037005 2022.3 [Reviewed]

DOI Web of Science CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人　電気化学会 Joint Work

A Li-excess cation-disordered rocksalt oxide, Li1.2Nb0.2V0.6O2, with higher theoretical capacity than traditional stoichiometric and layered oxides, is synthesized and tested as positive electrode materials for battery applications. Although Li1.2Nb0.2V0.6O2 cannot be synthesized by conventional calcination method, a single phase and metastable oxide is successfully synthesized by high-energy mechanical milling. Electrode performance of metastable and nanosized Li1.2Nb0.2V0.6O2 is significantly improved by heat treatment at 600 °C. Heat treated Li1.2Nb0.2V0.6O2 with a partial cation ordered layered structure delivers a high reversible specific capacity of 320 mAh g−1 on the basis of highly reversible two-electron redox of V ions. Moreover, inferior cyclability originating from the dissolution of V ions is successfully improved by using concentrate electrolyte solution, and over 90 % capacity retention is achieved after 50 cycles. This finding opens a new way to design high-capacity metastable Li-excess oxides for advanced Li-ion batteries with higher energy density.

Rational material design of Li-excess metal oxides with disordered rock salt structure

Naoaki Yabuuchi

Current Opinion in Electrochemistry 34 100978 2022.3 [Reviewed] [Invited]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：Elsevier Single Work

Magnetic Compton Scattering Study of Li-Rich Battery Materials

Kosuke Suzuki, Yuji Otsuka, Kazushi Hoshi, Hiroshi Sakurai, Naruki Tsuji, Kentaro Yamamoto, Naoaki … Show more authors

Condensed Matter 7 ( 1 ) 4 2022.3 [Reviewed]

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Language：English Publishing type：Research paper (scientific journal) Joint Work

Rocksalt and Layered Metal Sulfides for Li Storage Applications: LiMe0.5Ti0.5S2 (Me = Fe2+, Mn2+, and Mg2+)

Miyuki Shinoda, Hongahally Basappa Rajendra, Naoaki Yabuuchi

ACS Applied Energy Materials 5 ( 3 ) 2642 - 2646 2022.2 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Highly Graphitic Carbon Coating on Li1.25Nb0.25V0.5O2 Derived from a Precursor with a Perylene Core for High-Power Battery Applications

Ruijie Qi, Itsuki Konuma, Benoît D. L. Campéon, Yuko Kaneda, Masashi Kondo, Naoaki Yabuuchi

Chemistry of materials 34 ( 4 ) 1946 - 1955 2022.2 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Nanosized and metastable molybdenum oxides as negative electrode materials for durable high-energy aqueous Li-ion batteries

Yun Jeongsik, Sagehashi Ryota, Sato Yoshihiko, Masuda Takuya, Hoshino Satoshi, Rajendra Hongahally … Show more authors

PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 118 ( 48 ) 2021.11 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Nanosized and metastable molybdenum oxides as negative electrode materials for durable high-energy aqueous Li-ion batteries

Yun Jeongsik, Sagehashi Ryota, Sato Yoshihiko, Masuda Takuya, Hoshino Satoshi, Rajendra Hongahally … Show more authors

Proceedings of the National Academy of Sciences of the United States of America 118 ( 48 ) 2021.11

CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：National Academy of Sciences Joint Work

The development of inherently safe energy devices is a key challenge, and aqueous Li-ion batteries draw large attention for this purpose. Due to the narrow electrochemical stable potential window of aqueous electrolytes, the energy density and the selection of negative electrode materials are significantly limited. For achieving durable and high-energy aqueous Li-ion batteries, the development of negative electrode materials exhibiting a large capacity and low potential without triggering decomposition of water is crucial. Herein, a type of a negative electrode material (i.e., LixNb2/7Mo3/7O2) is proposed for high-energy aqueous Li-ion batteries. LixNb2/7Mo3/7O2 delivers a large capacity of similar to 170 mA . h . g(-1) with a low operating potential range of 1.9 to 2.8 versus Li/Li+ in 21 m lithium bis(trifluoromethanesulfonyl)amide (LiTFSA) aqueous electrolyte. A full cell consisting of Li1.05Mn1.95O4/Li9/7Nb2/7Mo3/7O2 presents high energy density of 107 W . h . kg(-1) as the maximum value in 21 m LiTFSA aqueous electrolyte, and 73% in capacity retention is achieved after 2,000 cycles. Furthermore, hard X-ray photoelectron spectroscopy study reveals that a protective surface layer is formed at the surface of the negative electrode, by which the high-energy and durable aqueous batteries are realized with LixNb2/7Mo3/7O2. This work combines a high capacity with a safe negative electrode material through delivering the Mo-based oxide with unique nanosized and metastable characters.

Fundamentals of metal oxide/oxyfluoride electrodes for Li-/Na-ion batteries

Benoît Denis Louis Campéon and Naoaki Yabuuchi

Chemical Physics Reviews 2 ( 4 ) 2021.11 [Reviewed] [Invited]

DOI Web of Science CiNii Research

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：AIP Publishing Single Work

Lithium-ion batteries provide the development of a clean and sustainable society based on renewable energy resources. To further enhance energy density and reduce the cost of batteries, innovations on electrode materials and high-performance nickel-/cobalt-free materials are necessary. In this review, lithium-excess manganese-based electrode materials with layered/rock salt oxides/oxyfluorides are emphasized because of their potential ability to be utilized as advanced and low-cost lithium-ion batteries in the near future. For these emerging electrode materials, higher energy density is realized, compared with traditional layered materials based on nickel/cobalt ions, relying on anionic and/or cationic redox as multi-electron reactions. Although, currently, anionic redox suffers from degradation of reversibility on continuous cycles, significant progress on theoretical understanding and material design concepts has been made in the past several years. Recently, as alternatives to traditional layered materials, many disordered rock salt oxides, including metastable and nanosized oxyfluorides, have been also found as a new class of high-capacity electrode materials with anionic/cationic redox. In the later part, these new trends for the material design are also extended to the development of electrode materials for sodium-ion batteries. By reviewing the fundamental and recent research progress in metal oxide/oxyfluoride electrodes, a valuable guide for materials scientists in the field of batteries is provided to accelerate the industrial development of high-performance nickel-/cobalt-free electrode materials. (c) 2021 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Why is the O3 to O1 phase transition hindered in LiNiO2 on full delithiation?

Ikeda Naohiro, Konuma Itsuki, Rajendra Hongahally Basappa, Aida Taira, Yabuuchi Naoaki

JOURNAL OF MATERIALS CHEMISTRY A 9 ( 29 ) 15963 - 15967 2021.8 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Tomographic reconstruction of oxygen orbitals in lithium-rich battery materials

Hafiz Hasnain, Suzuki Kosuke, Barbiellini Bernardo, Tsuji Naruki, Yabuuchi Naoaki, Yamamoto Kentaro … Show more authors

NATURE 594 ( 7862 ) 213 - 216 2021.6 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Joint Work

Efficient Stabilization of Na Storage Reversibility by Ti Integration into O3-Type NaMnO2

Takuro Sato, Kazuki Yoshikawa, Wenwen Zhao, Tokio Kobayashi, Hongahally Basappa Rajendra, Masao Yon … Show more authors

Energy Material Advances 2021 9857563-1 - 9857563-12 2021.5 [Reviewed]

<YABUUCHI Naoaki>

Papers - YABUUCHI Naoaki