在LiCoO2电极中,对高速Li-ion间隙的纳米效应
Masashi Okubo1, Eiji Hosono, Jedeok Kim
1National Institute of Advanced Industrial Science and Technology (AIST), Umezono, 1-1-1, Tsukuba, Ibaraki 305-0012, Japan.
Journal of the American Chemical Society
|May 22, 2007
概括
实现了对纳米晶体氧化 (LiCoO2) 的尺寸控制合成. 最佳颗粒大小 (17纳米) 提高了高速率的能力,而极端纳米大小低于15纳米是有害的.
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
- 纳米技术纳米技术
背景情况:
- 高速能力对于现代电池技术至关重要.
- 电极中的缓慢离子扩散限制了充放电率.
- 纳米化提供了更大的表面积和更短的扩散路径,以实现更快的离子运输.
研究的目的:
- 建立一个大小控制的合成纳米晶体氧化 (LiCoO2).
- 系统地研究LiCoO2纳米粒子的结构和电化学特性.
- 为了确定最佳的纳米粒子大小,以提高电化学性能.
主要方法:
- 液热反应用于大小控制的LiCoO2纳米颗粒的合成.
- 粉末X射线衍射和拉曼光谱用于结构分析.
- 用于性能评估的电化学测量和理论分析.
主要成果:
- 在纳米晶体LiCoO2.2.中观察到格子扩张.
- 发现15nm以下的极端尺寸缩小对性能不利.
- 具有17nm粒子大小的纳米晶体LiCoO2显示出出色的高速率能力 (在100°C时1°C的65%).
结论:
- 通过水热方法可实现对LiCoO2纳米颗粒的尺寸控制合成.
- 颗粒大小对LiCoO2.2的结构和电化学特性产生重大影响.
- 大约17nm的最佳颗粒大小最大化了LiCoO2阴极的高速性能.
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