Development of high-power electrolytes optimizing Li+ and total ionic transport for Li+ based energy storage system

2022 Fiscal Year Final Research Report

• Project/Area Number: 21K20554
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0502:Inorganic/coordination chemistry, analytical chemistry, inorganic materials chemistry, energy-related chemistry, and related fields
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Chikaoka Yu 東京農工大学, 工学(系)研究科(研究院), 助教 (00908626)
• Project Period (FY): 2021-08-30 – 2023-03-31
• Keywords: リチウムイオン電池 / 電解液 / 溶液構造 / 低誘電率溶媒

Outline of Final Research Achievements

This study aimed to enhance the power performance of the Li-ion-based rechargeable batteries using a dual-cation electrolyte system consisting of the Li salt and the additional supporting electrolytic salt. Particularly, the combination of dimethyl carbonate (DMC) solvent which has a low dielectric, and a quaternary ammonium salt (SBPBF4) which has a high solubility to DMC solvent, realized higher Li+ ionic conductivity and higher total ionic conductivity than those of the conventional high-dielectric solvent system. Moreover, the DMC-based dual-cation system showed high power performance in the Li-ion-based energy storage device (Li4Ti5O12//activated carbon full-cell).

Free Research Field

電気化学

Academic Significance and Societal Importance of the Research Achievements

従来の電解液設計では、[1] Li塩の種類、[2] Li塩を溶かす溶媒、[3] Li塩の濃度という”3次元パラメータ”によって出力特性の向上を目指していた。本研究では4つ目のパラメータとして「異種イオンの混合」が高出力化に有効であることを示し、電解液設計パラメータの”4次元化”を提唱する点で学術的なインパクトが高い。さらにこの理論は、Li+をベースとした電解液設計だけでなく、ポストLi+電池として期待されるNa+, K+, Mg2+, Ca2+電池等への応用も期待できる点でも波及効果が大きい。