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191 results on '"Sano, Hikaru"'

8. Elucidating the mechanism of microscopic conduction in cathode composites for all-solid-state batteries through scanning spreading resistance microscopy.

Author

Gamo, Hirotada, Maeda, Yasushi, Kiyobayashi, Tetsu, Siroma, Zyun, and Sano, Hikaru

Abstract

The microstructure design of electrodes comprising active materials and solid electrolytes (SE) determines the conduction properties of the electrode composites and the overall battery performance of all-solid-state batteries (ASSBs). This correlation, which is generally evaluated using macroscopic parameters based on effective conductivity, can be understood through insights into the microscopic conduction mechanism. Here, we investigate the microscopic electronic conduction properties of LiNi0.5Co0.2Mn0.3O2 (NCM) cathode composites employed in ASSBs using scanning spreading resistance microscopy (SSRM). The cathode composites with low NCM volume fractions show a bimodal resistance distribution in the NCM domains, leading to capacity deficit due to sparse electronic conductive networks. A simulation of the 3D microstructure generated by machine learning suggests that the resistance component of the composite detected using SSRM is strongly influenced by the electronic contact resistance between the material directly beneath the probe and other materials. Our findings emphasize that high electrochemical utilization of ASSBs requires minimization of the electronic contact resistance between the cathode active materials. The combination of SSRM and 3D generative microstructure simulation enables the evaluation of the electronic contact resistance between particles within inhomogeneous composites, such as ASSB electrodes. This approach provides fundamental guidelines for optimizing microstructure design to achieve high-performance ASSBs. [ABSTRACT FROM AUTHOR]

Published
2024
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15. Surface Degeneration of Li3PS4–LiI Glass-Ceramic Electrolyte by Exposure to Humidity-Controlled Air and Its Recovery by Thermal Treatment

Author

SANO, Hikaru, primary, MORINO, Yusuke, additional, MATSUMURA, Yasuyuki, additional, KAWAMOTO, Koji, additional, HIGUCHI, Hiroyuki, additional, YAMAMOTO, Noriyuki, additional, MATSUDA, Atsunori, additional, TSUKASAKI, Hirofumi, additional, MORI, Shigeo, additional, SAKUDA, Atsushi, additional, and HAYASHI, Akitoshi, additional

Published
2023
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23. AC Impedance Analysis of the Degeneration and Recovery of Argyrodite Sulfide-Based Solid Electrolytes under Dry-Room-Simulated Condition

Author

SANO, Hikaru, primary, MORINO, Yusuke, additional, YABUKI, Akinori, additional, SATO, Shimpei, additional, ITAYAMA, Naohiko, additional, MATSUMURA, Yasuyuki, additional, IWASAKI, Masahiro, additional, TAKEHARA, Masahiro, additional, ABE, Takeshi, additional, ISHIGURO, Yasuo, additional, TAKAHASHI, Tsukasa, additional, MIYASHITA, Norihiko, additional, SAKUDA, Atsushi, additional, and HAYASHI, Akitoshi, additional

Published
2022
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43. Study of the solid electrolyte interphase of Li-O2 battery electrolyte by analytical transmission electron microscopy.

Author

Kitta, Mitsunori and Sano, Hikaru

Subjects
*SOLID electrolytes, *SOLID state batteries, *TRANSMISSION electron microscopy, *ELECTRIC batteries, *ELECTROLYTES, *LITHIUM-air batteries, *NEGATIVE electrode
Abstract

Investigation of solid electrolyte interphases (SEIs) on negative electrode surfaces is essential to improve the stable charge-discharge performance of rechargeable lithium-air batteries (Li-O2 batteries). In this study, a direct investigation of SEI films is conducted using analytical transmission electron microscopy (TEM). A thin Cu specimen is prefabricated for TEM observation and is utilised as a model substrate for SEI formation. The electrochemical cell constructed using dissolved oxygen in the electrolyte exhibits a greater electrochemical overpotential during the Li-metal deposition process than that constructed with a pristine electrolyte. This suggests that different electrochemical passivation features occur in each different electrochemical cell. TEM observation confirms that the surface film formed by O2 dissolute electrolyte is a polycrystalline Li2O film with a thickness of ~5 nm, whereas the film formed by the pristine electrolyte is organic-based, amorphous-like and 20–50 nm thick. The dissolved oxygen molecules are more easily reduced than the components of the electrolyte, leading to the formation of Li2O as a stable passivation SEI film, which is expected to exhibit good charge-discharge features during the operation of the Li-O2 battery. [ABSTRACT FROM AUTHOR]

Published
2020
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46. Formation of uniform ferrocenyl-terminated monolayer covalently bonded to Si using reaction of hydrogen-terminated Si(111) surface with vinylferrocene/n-decane solution by visible-light excitation

Author

Sano, Hikaru, Zhao, Mingxiu, Kasahara, Daiji, Murase, Kuniaki, Ichii, Takashi, and Sugimura, Hiroyuki

Subjects
Self-assembled monolayer, Electrochemically active, Cyclic voltammetry, Vinylferrocene, AFM, Ferrocenyl group
Abstract

Electrochemically active self-assembled monolayers (SAM) have been successfully fabricated with atomic-scale uniformity on a silicon (Si)(111) surface by immobilizing vinylferrocene (VFC) molecules through Si-C covalent bonds. The reaction of VFC with the hydrogen-terminated Si (H-Si)(111) surface was photochemically promoted by irradiation of visible light on a H-Si(111) substrate immersed in n-decane solution of VFC. We found that aggregation and polymerization of VFC was avoided when n-decane was used as a solvent. Voltammetric quantification revealed that the surface density of ferrocenyl groups was 1.4×10(-10)molcm(-2), i.e., 11% in substitution rate of Si-H bond. VFC-SAMs were then formed by the optimized preparation method on n-type and p-type Si wafers. VFC-SAM on n-type Si showed positive photo-responsivity, while VFC-SAM on p-type Si showed negative photo-responsivity.

Published
2011

47. Artificial Insemination with Canine Spermatozoa Frozen in a Skim Milk/Glucose-Based Extender

Author

Abe, Yasuyuki, Lee, Dong-Soo, Sano, Hikaru, Akiyama, Koji, Yanagimoto-Ueta, Yoshiko, Asano, Tomoyoshi, Suwa, Yoshinori, and Suzuki, Hiroshi

Subjects
Cryopreservation, endocrine system, urogenital system, Skim milk/glucose-based extender, Spermatozoa, Canine
Abstract

application/pdf, Due to the recent outbreak of avian influenza, transportation of frozen canine semen with egg yolk has been sharply restricted. Thus, there is urgent need to develop a novel egg yolk-free extender for freezing canine spermatozoa. In the present study, the effect of using skim milk/glucose (SG)-based extender without egg yolk on the motility and fertilizing capacity of canine spermatozoa frozen-thawed in the presence of glycerol was examined. There was a tendency for the proportion of motile spermatozoa exposed to SG-based extender for 3 h to be higher than that exposed for 1 h, but the difference was not significant. The motility and other viability parameters of canine spermatozoa after thawing were similar to those obtained with an egg yolk-based extender. When spermatozoa frozen with SG-based extender containing glycerol after 3 h exposure were transcervically inseminated into 2 recipient bitches, a total of 6 pups were obtained. These results suggest that a simple extender composed of skim milk, glucose and glycerol is useful for cryopreservation of canine spermatozoa, which may contribute to improved exchange of genetic material and efficient production of companion and working dogs, such as guide dogs for the blind.

Published
2008

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