A cyclic phosphate-based battery electrolyte for high voltage and safe operation
A cyclic phosphate-based battery electrolyte for high voltage and safe operation
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DOI：
10.1038/s41560-020-0567-z
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发表时间：
2020-03
期刊：
影响因子：
56.7
通讯作者：
Qifeng Zheng;Yuki Yamada;Rui Shang;Seongjae Ko;Yun-Yang Lee;Kijae Kim;E. Nakamura;A. Yamada
中科院分区：
文献类型：
--
作者：
Qifeng Zheng;Yuki Yamada;Rui Shang;Seongjae Ko;Yun-Yang Lee;Kijae Kim;E. Nakamura;A. Yamada
锂离子电池的传统电解液是1 M LiPF6和基于环碳酸酯的溶剂(例如，碳酸乙烯)的组合。缺乏合适的替代溶剂阻碍了对新功能电解液的进一步探索。在这里，我们设计并合成了一种用于锂离子电池的氟化环状磷酸盐溶剂2-(2，2，2-trifluoroethoxy)-1，3，2-dioxaphospholane 2-氧化物(TFEP)。我们的设计原理是，这种溶剂分子具有环状碳酸盐的熔融化学结构，可以形成稳定的固体电解质界面和有机磷酸盐，可以捕获氢自由基并防止燃烧。由0.95 MLin(SO2F)2In TFEP/2，2，2-三氟乙基甲基碳酸酯组成的电解液配方具有优良的阻燃性和零自熄灭时间，使石墨阳极(~0.1 V对锂)和高压LiNi0.5Mn1.5O4阴极(~4.7 V对锂)能够高度稳定地运行，从而优于传统的电解液。这项工作开辟了电解液开发具有更高能量密度的安全锂离子电池的新领域。
The traditional electrolyte for lithium-ion batteries is a combination of 1 M LiPF6with a cyclic carbonate-based solvent (for example, ethylene carbonate). The lack of a suitable alternative solvent has hindered further exploration of new functional electrolytes. Here we design and synthesize a fluorinated cyclic phosphate solvent, 2-(2,2,2-trifluoroethoxy)-1,3,2-dioxaphospholane 2-oxide (TFEP), for use in lithium-ion batteries. Our design rationale is that this solvent molecule has a fused chemical structure of cyclic carbonates that can form a stable solid electrolyte interphase and organic phosphates that can trap hydrogen radicals and prevent combustion. An electrolyte formula composed of 0.95 M LiN(SO2F)2in TFEP/2,2,2-trifluoroethyl methyl carbonate shows excellent non-flammability with zero self-extinguishing time and enables the highly stable operation of graphite anodes (~0.1 V versus lithium) and high-voltage LiNi0.5Mn1.5O4cathodes (~4.7 V versus lithium), and thereby outperforms traditional electrolytes. This work opens up new frontiers in electrolyte developments towards safe lithium-ion batteries with higher energy densities.