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Ryoji Inada

Affiliation Department of Electrical and Electronic Information Engineering
Title Associate Professor
Fields of Research Energy Conversion Engineering / Electirical and Electronic Material Engineering / Electrochemistry
Degree Doctor of Engineering (Toyohashi University of Technology)
Academic Societies The Institute of Electric Engineers of Japan / The Japan Society of Applied Physics / The Electrochemical Society of Japan / The Ceramic Society of Japan / Cryogenics and Superconductivity Society of Japan / Material Research Society (USA)
E-mail inada@ee
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Laboratory website URL
Researcher information URL(researchmap) Researcher information


Main research subjects of our laboratory include:
(1)Research and development for oxide-based all-solid-state lithium-ion batteries.
(2)Research of new anode materials for highly safe lithium-ion batteries
(3)Research on environmental gas sensing devices using ceramic solid electrolyte

Theme1:Research and development for oxide-based all-solid-state lithium-ion batteries

Charge and discharge properties of LiV3O8 thick film electrode formed on Ta doped Li7La3Zr2O12 solid electrolyte.

All-solid-state lithium-ion batteries (LIBs), using nonflammable inorganic solid Li-ion conductor as an electrolyte, is expected as one of the next generation energy storage devices, because its safety and reliabilty are much superior to present LIB with flammable organic carbonate liquid electrolyte. However, development of solid electrolytes with both high Li-ion conductivity and minimizing interfacial resistance between solid electrolyte and electrodes are critical issues to be solved. To realize high performance all solid state LIBs, oxide solid electrolyte with high ionic conductivity and chemical stability against electrode materials are developed in our laboratory. In addition, fabrication process for solid-solid interface between electrode and solid electrolyte in solid state batteries is also studied.

Selected publications and works

(1) R. Inada, K. Okuno, S. Kito, T. Tojo, Y. Sakurai, Properties of lithium trivanadate film electrodes formed on garnet-type oxide solid electrolyte by aerosol deposition, Materials 11(9), 2018, 1570.
DOI: 103390/ma11091570
(2) R. Inada, S. Yasuda, H. Hosokawa, M. Saito, T. Tojo, Y. Sakurai, Formation and stability of interface between garnet-type Ta-doped Li7La3Zr2O12 solid electrolyte and lithium metal electrode, Batteries 4(2), 2018, 26.
DOI: 10.3390/batteries4020026
(3) R. Inada, T. Okada, A. Bando, T. Tojo, Y. Sakurai, Properties of garnet-type Li6La3ZrTaO12 solid electrolyte films fabricated by aerosol deposition method, Progress in Natural Science: Materials International 27, 2017, 350-355.
DOI: 10.1016/j.pnsc.2017.06.002
(4) R. Inada, S. Yasuda, M. Tojo, K. Tsuritani, T. Tojo, Y. Sakurai, Development of lithium stuffed garnet-type oxide solid electrolytes with high ionic conductivity for application to all-solid-state batteries, Frontiers in Energy Research 4, 2016, 26.
DOI: 10.3389/fenrg.2016.00028
(5) K. Kimura, K. Wagatsuma, T. Tojo, R. Inada, Y. Sakurai, Effect of composition on lithium-ion conductivity for perovskite-type lithium-strontium-tantalum-zirconium-oxide solid electrolytes, Ceramics International 42, 2016, 5546-5552.
DOI: 10.1016/j.ceramint.2015.12.133
(6) R. Inada, K. Ishida, M. Tojo, T. Okada, T. Tojo, Y. Sakurai, Properties of aerosol deposited NASICON-type Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte thin films, Ceramics International 41, 2015, 11136-11142.
DOI: 10.1016/j.ceramint.2015.05.062


All-solid-state battery, Oxide based solid electrolyte, Composite electrode, Aerosol deposition,Co-sintering process

Theme2:Research of new anode materials for advanced high-safety lithium-ion batteries

Crystal structure and charge-dicharge properties of different oxide anode materials.

Graphite is used as the dominant anode material for commercial lithium-ion batteries (LIBs). However, it intercalates Li-ion at a low potencial close to that of Li-plating, which results in a safety risk due to high surface Li-plating (Li dendrite, a potential cause of short circuits inside a battery). Lithium titanate Li4Ti5O12 (LTO) with cubic spinel structure is considered as an alternative anode material with high safety and excellent cycling stability, but its theoretical capacity is limited to 175 mAh/g, which is much smaller than graphite. Small capacity and high operation potential (1.5V vs. Li/Li+) of LTO sacrifices cell voltage and cell energy density seriously. To realize highly safe LIBs with high cell energy density, we are studying new anode materials with large capacity, good cycling stability and appropriate operating potential higher than that for Li-plating.

Selected publications and works

(1) T. Moritaka, Y. Yamashita, T. Tojo, R. Inaad, Y. Sakurai, Characterization of Sn4P3–carbon composite films for lithium-ion battery anode fabricated by aerosol deposition, Nanomaterials 9(7), 2019, 1032.
DOI: 10.3390/nano9071032
(2) T. Tojo, S. Kawashiri, T. Tsuda, M. Kadowaki, R. Inada, Y. Sakurai, Electrochemical performance of single Li4Ti5O12 particle for lithium-ion battery anode, Journal of Electroanalytical Chemistry 836, 2019, 24-29.
DOI: 10.1016/j.jelechem.2019.01.061
(3) R. Inada, R. Kumasaka, S. Inabe, T. Tojo, Y. Sakurai, Li+ insertion/extraction properties for TiNb2O7 single particle characterized by a particle-current collector integrated microelectrode, Journal of The Electrochemical Society 166, 2019, A5157-A5162.
DOI: 10.1149/2.0241903jes
(4) R. Inada, T. Mori, R. Kumasaka, R. Ito, T. Tojo, Y. Sakurai, Characterization of vacuum-annealed TiNb2O7 as high potential anode material for lithium-ion battery, International Journal of Applied Ceramic Technology 16, 2019, 264-272.
DOI: 10.1111/ijac.13058
(5) K. Narumi, T. Mori, R. Kumasaka, T. Tojo, R. Inada, Y. Sakurai, Syntheis and properties of Li3VO4-carbon composite as negative electrode for lithium-ion battery, AIP Conference Proceedings 1865, 2017, 060004.
DOI: 10.1063/1.4993380
(6) T. Takashima, T. Tojo, R. Inada, Y. Sakurai, Characterization of mixed titanium-niobium oxide Ti2Nb10O29 annealed in vacuum as anode material for lithium-ion battery, Journal of Power Sources 276, 2015, 113-119.
DOI: 10.1016/j.jpowsour.2014.11.109
(7) R. Inada, K. Shibukawa, C. Masada, Y. Nakanishi, Y. Sakurai, Characterization of as-deposited Li4Ti5O12 thin film electrode prepared by aerosol deposition method, Journal of Power Sources 253, 2014, 181-186.
DOI: 10.1016/j.jpowsour.2013.12.084


Highly safe anode materials, Lithium titanate, Titanium-niobium mixed oxide, Lithium vanadate, Metal phosphide

Theme3:Research on environmental gas sensing devices using oxide-based solid electrolyte


In recent years, development of detection technologies of oxygen-containing gases such as NOx, CO2, SOx, etc., which are of great interest as environmental pollutants, is required in various fields. An electrochemical cell involving a solid electrolyte (ionic conducting ceramics) and a gas to be detected can be applied as a sensing device operating over a wide temperature range, depending on the selection of constituent materials. We focus on oxide-based solid electrolyte materials that we have been studying for all solid-state batteries, and are conducting research on simple, cheap and robust gas sensing devices.

Selected publications and works

(1) K. Kimura, K. Wagatsuma, T. Tojo, R. Inada, Y. Sakurai, Effect of composition on lithium-ion conductivity for perovskite-type lithium-strontium-tantalum-zirconium-oxide solid electrolytes, Ceramics International 42, 2016, 5546-5552.
DOI: 10.1016/j.ceramint.2015.12.133
(2) R. Inada, K. Kusakabe, T. Tanaka, S. Kudo, Y. Sakurai, Synthesis and properties of Al-free Li7-xLa3Zr2-xTaxO12 garnet related oxides, Solid State ionics 262, 2014, 568-572.
DOI: 10.1016/j.ssi.2014.04.005
(3) R. Inada, K. Kimura, K. Kusakabe, T. Tojo, Y. Sakurai, Synthesis and lithium-ion conductivity for perovskite-type Li3/8Sr7/16Ta3/4Zr1/4O3 solid electrolyte by powder-bed sintering, Solid State Ionics 261, 2014, 95-99.
DOI: 10.1016/j.ssi.2013.09.008


Solid electrolyte, Ceramics, Gas sensing

Title of class

Electric Machinery 2 (B12530070) / Electrical Power Engineering 2 (B12620050) / Electrical Energy Conversion (M22622020) / Electrical Systems (M22622010) / Advanced Electrical Systems 2 (D32030040) / Advanced Electrical Systems 2(D52030040)/ Electrical Technology and Materials 2(M42630190)

Others (Awards, Committees, Board members)

2010: Excellent Paper Award for Young Scientists, The 11th IUMRS International Conference in Asia (IUMRS-ICA 2010)

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