Aromatic heterocyclic anion based ionic liquids and electrolytes
Journal article, 2023

Five new ionic materials comprising fluorine-free aromatic heterocyclic anions based on pyridine and pyrazine combined with a common n-tetrabutylphosphonium cation, (P4444)+, result in two room temperature ionic liquids (RTILs), one semi-solid, and two organic ionic plastic crystals (OIPCs) with melting points >20 °C. The OIPCs showed a plastic crystalline phase, multiple solid-solid transitions, and plastic crystalline and melt phases. For both the neat RTILs and the Li+ conducting electrolytes, the nature and strength of the ion-ion interactions mainly depend on the position of the nitrogen atom with respect to the carboxylate group in the anions. Furthermore, for the RTILs the ionic conductivity is effected by the electronic structure and flexibility of the ions and the anions diffuse faster than the (P4444)+ cation, but are slowed down in the electrolytes due to the strong electrostatic interactions between the carboxylate group of the anions and the Li+, as shown both experimentally and computationally. Overall, this study describes the effect of structural tuning of aromatic anions on the ion-ion interactions and introduces new ionic materials with promising properties to be used as solid and liquid electrolytes in energy storage devices.

Author

Mukhtiar Ahmed

Luleå University of Technology

Soniya Rao

Chalmers, Physics, Materials Physics

Andrei Filippov

Luleå University of Technology

Patrik Johansson

Chalmers, Physics, Materials Physics

Faiz Ullah Shah

Luleå University of Technology

Physical Chemistry Chemical Physics

1463-9076 (ISSN) 1463-9084 (eISSN)

Vol. 25 4 3502-3512

Enabling Safer Batteries via Click-Chemistry Created Fluorine-Free Electrolytes

Swedish Energy Agency (48194-1), 2020-01-01 -- 2023-12-31.

Subject Categories

Physical Chemistry

Materials Chemistry

DOI

10.1039/d2cp05272e

PubMed

36637119

More information

Latest update

3/7/2024 9