4.6 V LiCoO2の安定した高容量のためのスピン状態変調によるCo/O帯の重複を減らす
Jicheng Zhang1, Deniz Wong2, Qinghua Zhang3
1Center of Materials Science and Optoelectronics Engineering, College of Materials Science and Optoelectronic Technology, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
Journal of the American Chemical Society
|April 25, 2023
まとめ
設計された高スピンリチウムコバルト酸化物 (LCO) は,高圧電池の性能と安定性を向上させるために,有害な酸素アニオンリドックス (OAR) を抑制します.
科学分野:
- 材料科学
- 電気化学
- 固体化学
背景:
- 高電圧のリチウムコバルト酸化物 (LCO) は高い特異性を持っていますが,酸素の放出や容量低下などの課題に直面しています.
- これらの問題は,高圧での酸素アニオンリドックス (OAR) の不利な熱力学と運動学から生じる.
- 既存のLCOカトッドは構造的に不安定で,容量が急速に低下し,実用的な応用が制限されています.
研究 の 目的:
- 安定性と性能を向上させる高電圧LCOカトドを開発する.
- LCO電池の酸素の放出と構造的な分解の問題に根本的に取り組むこと.
- バッテリーの長寿のために酸素アニオンリドックスを抑制しながらコバルトリドックスを促進します.
主な方法:
- 高スピンリチウムコバルト酸化物 (LCO) の原子工学.
- レドックスメカニズムを調整して 酸素アニオン・レドックスよりも コバルト・レドックスを好むように
- 電子構造と相変異を高度な特徴化技術を用いて調査する.
主要な成果:
- エンジニアリングされたLCOの高スピンCoネットワークはOARを抑制し,酸素の放出と有害なCOの減少を減少させます.
- 不良なO3 → H1-3相移行は排除され,構造的整合性を高めます.
- 調節されたLCOは,超高レート容量 (1°Cで216 mAhg−1,5°Cで195 mAhg−1) と優れた容量保持 (90.4% @100サイクル,86.9% @500サイクル) を示しています.
結論:
- 原子的に設計された高スピンLCOは,高電圧カトドのOARの限界を克服する共支配的還元機構を可能にします.
- このアプローチは,電気化学的性能,構造的安定性,およびサイクル寿命を大幅に改善します.
- この発見は,高エネルギー密度の電池のための高度なカトド材料の設計のための新しい戦略を提供します.
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