Development of safe and high-performance secondary batteries based on nanotubes and assessment of their impacts on reduction of greenhouse gas emission

2023 Fiscal Year Final Research Report

• Project/Area Number: 21H04633
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Medium-sized Section 27:Chemical engineering and related fields
• Research Institution: Waseda University
• Principal Investigator: Noda Suguru 早稲田大学, 理工学術院, 教授 (50312997)
• Project Period (FY): 2021-04-05 – 2024-03-31
• Keywords: 二次電池 / カーボンナノチューブ / 窒化ホウ素ナノチューブ / 安全 / 高性能 / 低炭素化 / 技術評価 / ライフサイクルアセスメント

Outline of Final Research Achievements

To improve the performance and safety of lithium-ion batteries (LIBs) while reducing their environmental impact, we concurrently developed and assessed new technologies. We developed a self-supporting film electrode consisting only of carbon nanotubes (CNTs) and active material particles, and achieved high energy density with Li anode-Li2S8 cathode full cells and good cycle characteristics with SiO anode-NCM cathode full cells. Furthermore, 150°C operation was also achieved with Li anode-LTO cathode full cells using a self-supporting film of insulative boron nitride nanotubes (BNNTs) as the separator. Life cycle assessment (LCA) was also made to evaluate the greenhouse gas (GHG) emissions associated with battery manufacturing, and revealed that while the absence of metal foil reduces GHGs, the reduction of Li anode and solvents is important to reduce the GHGs emissions.

Free Research Field

反応工学、材料プロセス、ナノテクノロジー

Academic Significance and Societal Importance of the Research Achievements

LIBは製造に大きなGHG排出を伴い、Li、Co、NiやCuなどの資源にも問題を有す。本研究ではCNTと活物質のみで電極を構築して補助材料を削減、各種の正極・負極材を用いて全電池を実証した。性能に加え安全性の担保も欠かせない。耐熱性に優れるBNNTセパレータとイオン液体電解液を用いて150℃の高温全電池動作を達成した。開発技術の環境影響の客観的・定量的な評価も欠かせない。Li負極-Li2S8正極全電池に対してLCAを実施、硫黄正極と金属箔削減はGHG排出を削減するが、Li負極や溶媒の負荷が大きいことを見出した。新技術の開発と評価の両輪の実践によりその有効性を示した。