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Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Deviations from ideality in mixtures of two ionic liquids containing a common ion
José N Canongia Lopes1, Telma C Cordeiro, José M S S Esperança
1Centro de Química Estrutural, Instituto Superior Técnico, 1049-001 Lisboa, Portugal. jnlopes@ist.utl.pt
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Excess molar volumes were measured for binary mixtures of ionic liquids. Results show small, positive volumes, indicating minimal changes upon mixing, and correlate with cation alkyl chain length differences.
Area of Science:
- Physical Chemistry
- Materials Science
- Thermodynamics
Background:
- Ionic liquids (ILs) are salts that are liquid below 100°C, with tunable properties.
- Understanding IL mixing behavior is crucial for designing new materials and processes.
- Binary mixtures of imidazolium-based ILs with bis(trifluoromethylsulfonyl)amide anion were investigated.
Purpose of the Study:
- To measure excess molar volumes (V(E)) for binary mixtures of ILs.
- To analyze the mixing process of ILs with common or varying cations and anions.
- To investigate the influence of alkyl chain length and anion type on V(E).
Main Methods:
- Experimental measurement of excess molar volumes for six ([C(m)mim][NTf(2)] + [C(n)mim][NTf(2)]) and three ([C(4)mim][NTf(2)] + [PF(6)]), ([C(4)mim][NTf(2)] + [BF(4)]), and ([C(4)mim][BF(4)] + [PF(6)]) systems.
- Measurements conducted at 298 K and 333 K.
- Application of Flory theory for correlation with excess enthalpies.
Main Results:
- All studied IL binary mixtures exhibited small, positive excess molar volumes (V(E)).
- V(E) values were largely independent of temperature and pressure.
- V(E) showed additive trends, increasing with greater differences in cation alkyl chain lengths.
Conclusions:
- The mixing of ILs with common cations and varying anions, or vice versa, results in minimal volume changes.
- Flory theory offers a useful semiquantitative correlation for V(E) and excess enthalpies in these IL mixtures.
- Findings contribute to the understanding of IL solution thermodynamics and structure-property relationships.
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