リチウムとMnに富んだ層状カソッド材料における熱駆動リチウム再分配による表面対量リドックス結合
Shaofeng Li1,2, Sang-Jun Lee1, Xuelong Wang3,4
1Stanford Synchrotron Radiation Lightsource , SLAC National Accelerator Laboratory , Menlo Park , California 94025 , United States.
Journal of the American Chemical Society
|July 10, 2019
まとめ
リチウムとマンガンの豊富な (LMR) カトド材料における軽度の高温は酸化還元結合を誘発する. この研究は,LMR材料における酸素アニオンと移行金属の間の熱的に誘導された電荷移転を明らかにしています.
科学分野:
- 材料科学
- 電気化学
- エネルギー貯蔵
背景:
- リチウムとマンガンの豊富な (LMR) 層状のカトド材料は,移行金属と酸素アニオンの結合レドックス活性により,高い容量とエネルギー密度を提供します.
- LMR カソッドの電気化学的還元過程は,環境温度でよく研究されています.
- 特に非電気化学的条件下での,LMR カソッドの振る舞いに対する熱的影響は,ほとんど未調査のままである.
研究 の 目的:
- 軽度の高温 (~100 °Cまで) で,電荷を帯びたLi1.2Ni0.15Co0.1Mn0.55O2 (LMR) の材料における熱誘導による還元作用を調査する.
- 電気化学的な駆動力がない状態で,温度による影響を受けた表面から大量への酸化還元相互作用を理解する.
主な方法:
- 充電されたLi1.2Ni0.15Co0.1Mn0.55O2物質の体系的な研究
- 表面から大量への酸化還元結合を誘導するために,軽度の熱的ストレス (~100 °Cまで) を適用する.
- 酸素アニオンと移行金属カチオン間の電荷移転機構の分析.
主要な成果:
- ~100 °CでのLMR材料における大量酸素アニオンと表面移行金属カチオン間の電荷移転の最初の観測.
- この電荷の移転は,リチウムイオンの熱的に誘導された再分配に起因する.
- 軽度な熱的干渉下での深層デリチウム化LMR材料のダイナミックな非均衡状態の実証.
結論:
- わずかに上昇した温度では,電気化学的なサイクルとは無関係に,LMRのカトド材料で有意な酸化還元活性が誘発されます.
- この発見は,LMR材料の熱安定性に関する考察が実用的な応用において重要であることを強調しています.
- 先進的なバッテリー技術の性能と安全性を最適化するために,これらの熱的に駆動されたプロセスを理解することは極めて重要です.
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