<p>A detailed NMR study of translational and reorientation mobility in mixtures of [BMPyrrTFSI] with [LiTFSI] (0; 0.1 and 1.5&#xa0;mol/kg) was carried out in the temperature range of 278&#xa0;K ≤ T ≤ 333&#xa0;K. To realize the NMR advantage, the resonances of the <sup>1</sup>H, <sup>13</sup>C, <sup>7</sup>Li, and <sup>19</sup>F nuclei were registered. The diffusion data clearly indicate a strong correlation of the translational motion of all ions in the studied objects at all used temperatures. On the basis of the data obtained, the activation energies, <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({E}_{a}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mi>a</mi> </msub> </math></EquationSource> </InlineEquation>, for translational motion have also been calculated. The energy barriers for the translational diffusion of the IL cations and anions are close, but for the movement of the Li<sup>+</sup> cations, the activation energy <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\({E}_{a}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>E</mi> <mi>a</mi> </msub> </math></EquationSource> </InlineEquation> is significantly greater. It follows that the lithium cation moves together with the solvate shell of a certain number of anions. To investigate the local mobility, the temperature dependences of the spin–lattice relaxation rates in the studied systems were measured. A comparison of the activation energy values calculated from diffusion and NMR-relaxation data indicates that the energy barriers for the translational motion of ions in the system under study are much higher than for local reorientation processes. The data obtained confirm the conclusion that there is a strong solvate shell (big <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\({\tau}_{c}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>τ</mi> <mi>c</mi> </msub> </math></EquationSource> </InlineEquation>) around lithium cations.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Translational and Reorientational Mobility of Ions in the “BMPyrrTFSI–LithiumTFSI” System According to NMR Data

  • Konstantin V. Tyutyukin,
  • Alexandr V. Ievlev,
  • Oscar Cabeza,
  • Luis M. Varela,
  • Vladimir V. Chizhik

摘要

A detailed NMR study of translational and reorientation mobility in mixtures of [BMPyrrTFSI] with [LiTFSI] (0; 0.1 and 1.5 mol/kg) was carried out in the temperature range of 278 K ≤ T ≤ 333 K. To realize the NMR advantage, the resonances of the 1H, 13C, 7Li, and 19F nuclei were registered. The diffusion data clearly indicate a strong correlation of the translational motion of all ions in the studied objects at all used temperatures. On the basis of the data obtained, the activation energies, \({E}_{a}\) E a , for translational motion have also been calculated. The energy barriers for the translational diffusion of the IL cations and anions are close, but for the movement of the Li+ cations, the activation energy \({E}_{a}\) E a is significantly greater. It follows that the lithium cation moves together with the solvate shell of a certain number of anions. To investigate the local mobility, the temperature dependences of the spin–lattice relaxation rates in the studied systems were measured. A comparison of the activation energy values calculated from diffusion and NMR-relaxation data indicates that the energy barriers for the translational motion of ions in the system under study are much higher than for local reorientation processes. The data obtained confirm the conclusion that there is a strong solvate shell (big \({\tau}_{c}\) τ c ) around lithium cations.