Li-O2電池の充電電圧を増やすためのポジティブフィードバックメカニズム
Yoko Hase1, Takeshi Uyama1, Kiho Nishioka2
1Toyota Central R&D Laboratories, Inc., 41-1 Yokomichi, Nagakute, Aichi 480-1192, Japan.
Journal of the American Chemical Society
|January 11, 2022
まとめ
リチウム酸素電池の充電過剰は,リチウム2−O2脱リチウム化中に発生するポジティブフィードバックループに起因する. 酸化率,電圧,またはLi+拡散の変化を抑制すると,バッテリーの効率が向上します.
科学分野:
- 電気化学
- 材料科学
- エネルギー貯蔵
背景:
- 非水性Li-O2電池は大きな充電過剰に苦しんでおり,低効率と材料の劣化につながる.
- 複雑な反応メカニズムは,これらの過剰の可能性の完全な理解を妨げます.
研究 の 目的:
- 充電中に過剰電位が増加した特定の反応ステップを調査します.
- セル電圧をエスカレートするポジティブフィードバックメカニズムの起源を明らかにします.
主な方法:
- リートヴェルド製のex situ粉末X線微分法を用いた.
- ガルバノスタティック・インターミテント・タイトレーション (GITT) テクニックを用いた.
- Li2-O2相の構造的および電気化学的性質を分析した.
主要な成果:
- 充電中に存在するLi2-O2フェーズを特定しました.
- 速度を決定するステップとして固体溶液脱塩を決定する.
- 電圧が増加するとLi+ 拡散係数 (DLi) が低下し,酸化速度が減速し,電圧が増加する.
結論:
- プラスのフィードバックループは,初期充電段階でセル電圧を本質的に増加させます.
- 充電プロセスの継続性を拡張するには,酸化率,セル電圧,DLiを安定させることが可能である.
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