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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 / Non-Destructive Testing
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 Researcher information


Main research subjects of our laboratory include:
(1)Research and development for all-solid-state lithium-ion batteries.
(2)Research of new anode materials for highly safe lithium-ion batteries
(3)Non-destructive magnetic testing method for batteries.

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

Charge and discharge properties of TiNb2O7 film electrode on 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, aerosol deposition (AD) method, which is polycrystalline ceramic film formation process under room temperature, is applied for novel fabrication process of all-solid-state LIBs.

Selected publications and works

(1) 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
(2) 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 4:28, 2016.
doi: 10.3389/fenrg.2016.00028
(3) 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
(4) 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
(5) 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.2013.09.008


All solid state battery, Oxide based solid electrolyte, Aerosol deposition

Theme2:Research of new anode materials for highly safe 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) 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
(2) 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
(3) 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

Theme3:Non-destructive magnetic testing method for batteries

Magnetic field distribution caused by magnetized Fe particle (ca. 0.1mm) included in LiCoO2 electrode.

Since energy density in lithium-ion battery (LIB) is quite large and flammable organic carbonate liquid solution is used as electrolyte, battery failure could cause serious accidents such as explosion and ignition. Safety risk of LIBs becomes a social problem and an obstacle for large scale application such as HEV, EV and stationary load-leveling system. To improve safety and reliability of LIBs, novel mesuring technique to detect the battery failure before serious accident happens is strongly required, together with the improvement of materials and structure of batteries. In our labolatory, non-destructive magnetic testing methods are studied to detect small metallic contamination during fabrication stage of battery component. It is worth to note that our measurement method is also applicable for evaluation of non-uniformity of high-Tc superconducting wires, defect in various steels, etc..

Selected publications and works

(1) T. Makihara, R. Inada, A. Oota, S. Sakamoto, C.S. Li, P.X. Zhang, Evaluation of self-field distributions for Bi2223 tapes with oxide barriers carrying DC transport current, IEEE Trans. Appl. Supercond. 21, 2011, 2820-2823.
doi: 10.1109/TASC.2010.2091241
(2) R. Inada, S. Baba, R. Ohtsu, T. Makihara, S. Sakamoto, A. Oota, Longitudinal uniformity of commercial Bi2223 tapes characterized by scanning Hall-probe microscopy, IEEE Trans. Appl. Supercond. 21, 2011, 2816-2819.
doi: 10.1109/TASC.2010.2091615


Non-destructive magnetic testing, Detection of metallic contaminant, Magnetic sensor

Title of class

Electric Machinery 2 (B12530070) / Electrical Power Engineering 2 (B12620050) / Electrical Energy Conversion (M22622020) / 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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