在立方石榴石固体电解质中离子导电性的多诱导调节:一项第一原则研究
Feye-Feng Lu1, Hong-Kang Tian1,2,3
1Department of Chemical Engineering, National Cheng Kung University, Tainan 70101, Taiwan. hktian@gs.ncku.edu.tw.
Physical chemistry chemical physics : PCCP
|July 6, 2023
概括
使用Ga或Fe的Doping立方石榴石Li7La3Zr2O12 (c-LLZO) 通过改变化学潜力来增强离子导电性. 然而,由于明显的电荷分布效应,兴奋剂会降低导电性.
科学领域:
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
- 计算材料科学科学 计算材料科学
背景情况:
- 立方石榴石Li7La3Zr2O12 (c-LLZO) 是所有固态电池的关键固体电解质.
- 用Ga,Al或Fe合c-LLZO稳定了结构,并改善了离子导电性.
- +3电荷剂对离子导电性的影响有很大差异,需要进一步研究.
研究的目的:
- 通过使用DFT,研究Ga,Fe和Al剂对Li化学潜力和c-LLZO中的Li离子导电性的影响.
- 为了确定有利的剂位置,并确定Fe剂的最佳DFT+U参数.
- 阐明剂诱导的电荷分布与离子传输机制之间的关系.
主要方法:
- 使用密度函数理论 (DFT) 的计算,包括 DFT+U.
- 在c-LLZO中确定了能量有利的剂位点.
- 分析包括预测的状态密度,电荷密度和巴德电荷分析.
主要成果:
- Ga和Fe的注增加了Li的化学潜力 (0.05-0.08 eV),降低了转移障碍,提高了导电性.
- 兴奋剂降低了Li化学潜力 (0.08 eV),增加了吸引力,降低了导电性.
- 在剂周围的明显的电荷分布对离子的化学潜力和导电性产生了重大影响.
结论:
- 在剂和原子周围的局部电荷分布对于c-LLZO中的离子导电性至关重要.
- 加和铁剂通过在相邻的氧气上产生更多的正电荷来增强导电性,破坏了离子的稳定.
- 兴奋剂降低了导电能力,原因是离子和氧原子之间的吸引力增加.
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