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Updated: Dec 20, 2025

Synthesis of Ionic Liquid Based Electrolytes, Assembly of Li-ion Batteries, and Measurements of Performance at High Temperature
Published on: December 20, 2016
Comparing the Thermal and Electrochemical Stabilities of Two Structurally Similar Ionic Liquids
Faiz Ullah Shah1, Inayat Ali Khan1, Patrik Johansson2
1Chemistry of Interfaces, Luleå University of Technology, SE-971 87 Luleå, Sweden.
Abstract:
Here we focus on the thermal and variable temperature electrochemical stabilities of two ionic liquids (ILs) having a common tributyloctyl phosphonium cation [P4,4,4,8]+ and two different orthoborate anions: bis(mandelato)borate [BMB]- and bis(salicylato)borate [BScB]-. The thermo-gravimetric analysis data suggest that [P4,4,4,8][BScB] is thermally more stable than [P4,4,4,8][BMB] in both nitrogen atmosphere and air, while the impedance spectroscopy reveals that [P4,4,4,8][BScB] has higher ionic conductivity than [P4,4,4,8][BMB] over the whole studied temperature range. In contrast, the electrochemical studies confirm that [P4,4,4,8][BMB] is more stable and exhibits a wider electrochemical stability window (ESW) on a glassy carbon electrode surface as compared to [P4,4,4,8][BScB]. A continuous decrease in the ESWs of both ILs is observed as a function of operation temperature.
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