揭示了固体电解质间相在设计稳定,快充,低温离子电池中的作用
Lei Tao1, Hanrui Zhang2, Sameep Rajubhai Shah3
1Department of Chemistry, Virginia Tech, Blacksburg, VA 24061.
概括
优化离子电池的固体电解质间相 (SEI) 需要平衡被动化和离子传输. 在SEI中分散的化 (LiF) 提高了性能,使其能够稳定,快速充电,低温运行.
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
- 储能 储能 储能 储能 储能 储能
背景情况:
- 设计固体电解质介面 (SEI) 对于先进的离子电池 (LIB) 来说至关重要.
- 一个常见的策略是创建富含化 (LiF) 的化SEI,尽管LiF的离子导电性很低.
- 对化物SEI的相互矛盾的发现凸显了需要考虑LiF的空间分布,而不仅仅是它的存在.
研究的目的:
- 调查 LiF 在 SEI 的空间分布对电池性能的影响.
- 为了确定稳定,快速充电,低温LIB的最佳SEI特性.
- 确定促进有利的SEI结构的电解质配方.
主要方法:
- 对各种阳极材料 (石墨,Si/石墨,Si) 进行电化学测试,使用一种新型电解质 (2-甲基四水中的1M LiPF6).
- 使用分层阴极的囊细胞的制造和测试.
- 实验分析和SEI组成和形态学的理论建模.
主要成果:
- 在SEI中过度,密集的LiF阻碍了离子运输.
- 在SEI内分散的LiF增强了离子导电性,可能是通过异质接口.
- 在2-甲基四基电解质中的1M LiPF6产生了分散LiF的SEI,使得稳定的99.9%库伦比效率和在低温下优异的速率能力能够适用于多种阳极类型.
结论:
- 在SEI中LiF的空间分布对电池性能至关重要,而不仅仅是它的存在.
- 使用1M LiPF6在2-甲基四基中实现的具有良好分散LiF的SEI是稳定,高性能低温LIB的关键.
- 这种方法促进了稳定的循环 (>1000个循环) 和特殊的速度能力下降到-20°C在袋式电池.
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