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Ab initio study of the operating mechanisms of tris(trimethylsilyl) phosphite as a multifunctional additive for Li-ion batteries
Journal of Power Sources ( IF 8.1 ) Pub Date : 2017-04-22 , DOI: 10.1016/j.jpowsour.2017.04.062
Dong Young Kim , Hosang Park , Woon Ih Choi , Basab Roy , Jinah Seo , Insun Park , Jin Hae Kim , Jong Hwan Park , Yoon-Sok Kang , Meiten Koh

Tris(trimethylsilyl) phosphite (P(OSi(CH3)3)3) is a multifunctional electrolyte additive for scavenging HF and forming a cathode electrolyte interphase (CEI). Systematic analysis of the HF reaction pathways and redox potentials of P(OSi(CH3)3)3, OP(OSi(CH3)3)3, P(OSiF3)3, and OP(OSiF3)3, and their reaction products, using ab initio calculations allowed us to elucidate the operating mechanism of P(OSi(CH3)3)3 and verify the rules that determine its HF reaction pathways and electrochemical stability. While OSi cleavage is the predominant HF scavenging pathway for P(OSi(CH3)3)3, OP cleavage is stabilized by replacing CH3 with an electron-withdrawing group. Thus, P(OSiF3)3 scavenges HF mainly through OP cleavage to produce PF3, which has high oxidation stability. However, the OSi cleavage pathway produces P(OSi(CH3)3)2OH, P(OSi(CH3)3) (OH)2, and P(OH)3 sequentially, along with Si(CH3)3F. These PO3 systems, which are oxidized earlier than carbonate solutions and form tightly bonded units following oxidation, act as seed units for compact CEI growth. Moreover, the HF scavenging ability of PO3 systems is maintained during oxidation until all OSi bonds are broken. As a strategy for developing additives with enhanced functionality, modifying P(OSi(CH3)3)3 by replacing CH3 with an electron-donating group to exclusively utilize the OSi cleavage pathway for HF scavenging is recommended.



中文翻译:

从头开始研究亚磷酸三(三甲基甲硅烷基)酯作为锂离子电池多功能添加剂的工作机理

亚磷酸三(三甲基甲硅烷基)酯(P(OSi(CH 333)是一种多功能电解质添加剂,用于清除HF并形成阴极电解质中间相(CEI)。P(OSI(CH的HF反应途径和氧化还原电位的系统分析333,OP(OSI(CH 333,P(OSiF 33,和OP(OSiF 33,以及它们的反应产物,从头算开始,使我们可以阐明P(OSi(CH 333的作用机理并验证确定其HF反应途径和电化学稳定性的规则。虽然O Si裂解是P(OSi(CH 333的主要HF清除途径,但O P裂解通过用吸电子基团取代CH 3来稳定。因此,P(OSiF 33主要通过O P裂解清除HF以产生具有高氧化稳定性的PF 3。但是,O Si裂解途径会产生P(OSi(CH 332 OH,P(OSi(CH 33)(OH)2和P(OH)3依次沿有Si(CH 33 F.这些PO 3个系统,其比以下氧化作用,充当种子单位紧凑CEI生长碳酸盐溶液和形式紧密地结合单元更早氧化。此外,在氧化过程中保持PO 3体系的HF清除能力,直到所有O Si键断裂为止。作为开发具有增强功能的添加剂的策略,建议通过用给电子基团取代CH 3来修饰P(OSi(CH 333,以专门利用O Si裂解途径进行HF清除。

更新日期:2017-04-22
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