过氧化表面是金属的,而氧化表面不是金属的
Maxwell D Radin1, Jill F Rodriguez, Feng Tian
1Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-2125, USA.
Journal of the American Chemical Society
|December 14, 2011
概括
第一原则计算显示,稳定的过氧化表面是半金属和铁磁,与隔热氧化不同. 这些独特的电子特性解释了氧电池的电化学可逆性差异.
科学领域:
- 材料科学 材料科学 材料科学
- 电化学 电化学 电化学
- 计算化学计算化学
背景情况:
- 过氧化物 (Li(2) O(2) 和氧化 (Li(2) O) 是氧电池中的关键放电产物.
- 了解它们的表面特性对于优化电池性能和周期寿命至关重要.
研究的目的:
- 描述Li(2) O(2) 和Li(2) O表面的热力学稳定性和电子结构.
- 用第一原则计算和沃尔夫构造来识别稳定的表面面.
- 为了将表面特性与氧电池中观察到的电化学行为相关联.
主要方法:
- 用密度函数理论 (DFT) 的计算来研究40个表面.
- 评估了热力学稳定性,考虑到氧过结合错误.
- 分析了包括磁性特性在内的表面电子结构.
主要成果:
- 确定了几个新的,稳定的富含氧气的Li(2) O(2) 表面 ({0001}, {1 ̅100}).
- 稳定的Li(2) O(2) 表面表现出半金属的行为和铁磁性,由于表面的氧气.
- 稳定的Li(2) O表面是绝缘性和非磁性,而偏好的是静电平面.
结论:
- 独特的半金属和铁磁性质的Li(2) O(2) 表面,与隔热Li(2) O相比,解释了电池电化学可逆性的差异.
- 在Li(2) O(2) 上的导电表面路径可以减轻散装电子传输的限制,从而可能提高电池容量.
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