Abstract Two closely spaced a -type low resolution microwave band series were observed for the normal, 13 C and d 3 isotopic forms of methoxy difluorophosphinoxide. The lower frequency series of the three isotopic species was found and assigned using a pulse beam Fabry—Perot cavity Fourier transform microwave spectrometer. The a - and b -type spectra of the three species were fitted to a Watson hamiltonian
摘要 对于甲氧基二氟膦氧化物的正常、 13 C 和 d 3 同位素形式,观察到两个间隔很近的 a 型低分辨率微波波段系列。使用脉冲束法布里-珀罗腔傅里叶变换微波光谱仪发现并分配了三种同位素的较低频率系列。三种物种的 a - 和 b 型光谱拟合到沃森汉密尔顿,对于正常物种,A = 4568.215(1) MHz,B = 2500.471(9) MHz 和 C =2453.863(9) MHz。CH 3 OP(O)F 2 的斯塔克效应测量导致确定电偶极子分量 μ a =2.699(2) D 和 μ b =1.522(2) D。惯性矩和电偶极子数据表明最低能量构象具有 C s 对称性。数据与观察到的构象异构体对反式构型的分配最一致。在脉冲束腔光谱仪中未观察到的第二个 a 型低分辨率微波波段系列来自反式构象异构体的甲氧基扭转激发态或第二个更高能量的构象。在 a - 和 b - 型光谱中不存在 A-E
Initial stages of thermal decomposition of LiPF6-based lithium ion battery electrolytes by detailed Raman and NMR spectroscopy
the state-of-the-art lithium ion battery electrolytes based on LiPF6 in organic solvents have a low thermal abuse tolerance and poor cycle life at elevated temperatures. We present here a detailed investigation of the initialstages of the thermaldecomposition of LiPF6 in EC/DMC stored at 85 °C using Raman and NMR spectroscopy. During storage (up to 160 h), significant amounts of CO2 are evolved, as
与特定的电极化学性质无关,基于LiPF 6的最先进的锂离子电池电解质在有机溶剂中的耐热性低,并且在高温下的循环寿命差。在此,我们使用拉曼光谱和NMR光谱对在85°C下存储的EC / DMC中LiPF 6热分解的初始阶段进行详细研究。如在拉曼光谱中检测到的那样,在储存过程中(长达160小时),放出了大量的CO 2。时间分辨的1 H,31 P和19 F NMR光谱显示POF 3,POF(OH)2,POF 2(OCH 2 CH2) n F和POF 2 OMe作为反应性分解产物。我们独特的19 F NMR方法(在加热的同时以高能量和高时间分辨率进行测量)可以对进化出的物种进行首次定量分析,并揭示了在最初的30分钟至72小时内的几种分解反应,其中HF和POF的速率2 OMe的形成令人惊讶地是线性的。发现EC与DMC相比反应性低得多。所有信息都用于制定基于LiPF 6的电解质的更新分解路径图。