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：

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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 ₃）₃）₃）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₃）₃）₃，OP（OSI（CH ₃）₃）₃，P（OSiF ₃）₃，和OP（OSiF ₃）₃，以及它们的反应产物，使用从头算的方法使我们能够阐明P（OSi（CH ₃）₃）_3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OSi裂解是P（OSi（CH ₃）₃）₃的主要HF清除途径，但OP裂解通过用吸电子基团取代CH ₃得以稳定。因此，P（OSiF ₃）₃主要通过OP裂解来清除HF ，从而产生具有高氧化稳定性的PF ₃。但是，OSi裂解途径会依次产生P（OSi（CH ₃）₃）₂ OH，P（OSi（CH ₃）₃）（OH）₂和P（OH）₃以及Si（CH₃）₃ F.这些PO ₃系统比碳酸盐溶液更早被氧化，并在氧化后形成紧密结合的单元，充当致密CEI生长的种子单元。此外，在氧化过程中保持PO ₃系统的HF清除能力，直到所有OSi键均被破坏为止。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 ₃）₃）₃，以专门利用OSi裂解途径清除HF。