Development of Laminated Solid Electrolyte for Long-life All-solid-state Batteries with Lithium Metal Anode

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H02128
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 21010:Power engineering-related
• Research Institution: Toyohashi University of Technology
• Principal Investigator: Inada Ryoji 豊橋技術科学大学, 工学(系)研究科(研究院), 准教授 (30345954)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 酸化物固体電解質 / 金属リチウム負極 / 全固体電池 / 積層構造 / 界面抵抗

Outline of Final Research Achievements

To stably operate the metallic lithium (Li) anode in an all-solid-state battery using an oxide solid electrolyte (Ox-SE), we worked on the fabrication of Ox-SE having a laminated structure with a high-density and a low-density layers. In the high-density Ox-SE layer alone, the tolerance for Li dendrite growth (current density at which dendrite growth occur in the SE layer) was doubled at the beginning of this research. An Ox-SE thick film of the same composition was formed on a high-density Ox-SE layer using the aerosol deposition (AD) method, and then annealed at a specific temperature to form a low-density Ox-SE layer. However, when Li was plated on the end face of the low-density Ox-SE layer, the pores in the layer could not be effectively utilized, so that it is necessary to continue the study to overcome this issue.

Free Research Field

電気化学エネルギーデバイス

Academic Significance and Societal Importance of the Research Achievements

本研究課題の実施により，異種酸化物の微量添加や焼結条件の調整により高密度SE層の組織制御によって，積層化の前段階でLiデンドライト耐性の指標となる限界電流密度を，研究課題開始当初の2倍以上に相当する0.9mA/cm2まで向上できたのは，学術的に重要な成果である。一方，ガラス基板での予備検討を踏まえて，高密度SE層の上に，μmオーダーの空孔を有する低密度SE厚膜想を形成する条件を見出だすことはできたが，実際にLi析出を行った際に低密度層内の空孔が有効に活用できていない課題の解決に至らなかった。今後の継続検討によりこの課題を克服できれば，全固体電池の高エネルギー密度化に貢献できると考える。