受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞区分：国内学会・会議・シンポジウム等の賞  受賞国：日本国

受賞区分：国際学会・会議・シンポジウム等の賞  受賞国：インド

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：ACS Nano  

Redox reactions of the Li+ insertion/extraction from one to two interlayers of graphene (Gr) on area-defined single-crystalline SiC substrates are investigated using lithium phosphorus oxynitride glass (LiPON) as the solid-state electrolyte. Unlike an organic liquid electrolyte, this glassy electrolyte does not induce a reduction current and excludes the desolvation reaction of Li+. Gr electrodes with less than two Gr layers show a single reduction peak and one or two oxidation peaks below +0.21 V (vs Li+/Li), differing distinctly from those of graphite and multilayer Gr, which display multiple peaks (multiple stage transitions). However, this finding aligns with the conventional understanding that graphite stage structure transitions proceed with stepwise increases or decreases in the number of Gr layers between adjacent Li-inserted interlayers. Cyclic voltammetry measurements indicate the presence of surface capacity due to Li+ adsorption/desorption at the LiPON/Gr interface. Moreover, Li+ insertion and extraction induce different charge transfer resistances at the level of a single interlayer. These sensitive measurements are achieved using high-quality epitaxial Gr and LiPON electrolyte, which prevent the formation of a solid electrolyte interphase and the desolvation reaction of Li+. Similar measurements using bilayer Gr produced by chemical vapor deposition coupled with a Gr transfer method and an ethylene carbonate/dimethyl carbonate liquid electrolyte are not reliable. Thus, the proposed method is effective for electrochemical measurement of Gr electrodes with a controlled number of layers.

DOI： 10.1021/acsnano.3c00158

Web of Science

Scopus

PubMed

記述言語：英語   出版者・発行元：ACS Applied Materials and Interfaces  

Garnet-type Li7La3Zr2O12 (LLZ) has advantages of stability with Li metal and high Li+ ionic conductivity, achieving 1 × 10-3 S cm-1, but it is prone to react with electrode active materials during the sintering process. LISICON-type Li3.5Ge0.5V0.5O4 (LGVO) has the advantage of less reactivity with the electrode active material during the sintering process, but its ionic conductivity is on the order of 10-5 S cm-1. In this study, these two solid electrolytes are combined as a multilayer solid electrolyte sheet, where 2 μm thick LGVO films are coated on LLZ sheets to utilize the advantages of these two solid electrolytes. These two solid electrolytes adhere well through Ge diffusion without significant interfacial resistance. The LLZ-LGVO multilayer is combined with a LiCoO2 positive electrode and a lithium metal anode through annealing at 700 °C. The resultant all-solid-state battery can undergo repeated charge-discharge reactions for over 100 cycles at 25 or 60 °C. The LGVO coating suppresses the increases in the resistance from the solid electrolyte and interfacial resistance induced by annealing by ca. 1/40. As with sulfide-based all-solid-state batteries, function sharing of solid electrolytes will be a promising method for developing advanced oxide-based all-solid-state batteries through a sintering process.

DOI： 10.1021/acsami.2c10853

Web of Science

Scopus

PubMed

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Electrochemistry Communications  

Anti-NASICON-structured Fe2(MoO4)3 (FMO) thin films are formed on NASICON-structured LATP solid-state electrolyte by pulsed laser deposition, and their electrochemical properties are investigated. The FMO thin films operate at 3.0 V flat voltage vs. Li/Li+ within the potential window of LATP. The apparent diffusion coefficient of the FMO thin film on LATP is almost consistent with that measured in a conventional organic liquid electrolyte (0.5–1.2 × 10-12 cm2 s−1) and stable and fast charge–discharge reactions are realized. These results indicate that FMO/LATP is appropriate as a reference and counter electrode for all-solid-state batteries using NASICON-structured LATP. Combining crystalline electrode-solid electrolytes with a similar framework structure at relatively low temperatures will play an important role in realizing reversible electrode reactions. An all-solid-state battery, FMO/LATP/LiCoO2, is developed to apply the FMO as a reference and counter electrode, and the SSB operates at 1.0 V without visible capacity fading.

DOI： 10.1016/j.elecom.2021.107108

Web of Science

Scopus

記述言語：英語  

DOI： 10.1039/d0cp04598e

PubMed

担当区分：筆頭著者,　責任著者   記述言語：英語  

開催年月日： 2024年1月

会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

開催地：名古屋大学 野依記念学術交流館・カンファレンスホール  

開催年月日： 2023年10月

会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

開催地：東京都日本橋  

開催年月日： 2023年9月

会議種別：口頭発表（一般）  

開催地：熊本  

開催年月日： 2022年10月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2022年3月

記述言語：日本語   会議種別：ポスター発表