THE SYNTHESIS OF IMIDAZOLIUM-BASED IONIC LIQUIDS UTILIZING MAOS (MICROWAVE-ASSISTED ORGANIC SYNTHESIS) METHOD AND STUDY OF ITS ELECTROCHEMICAL PROPERTIES FOR LITHIUM-ION BATTERIES APPLICATION

• Main Author: Wahyu Agung, Gilang
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/52132
• Institution: Institut Teknologi Bandung

Lithium ion batteries (Li-ion Batteries) are a type of battery that is commonly used in everyday life, however organic solvent that is often used in commercial Li-ion batteries has poor thermal stability and thus its safety level needs to be improved. Therefore, ionic liquids can be used as alternative to replace organic solvent. In this study, 1-decyl-3-methylimidazolium bromide ([DMIm]Br) and 1-dodecyl-3-methylimidazolium bromide ([DDMIm]Br) ionic liquids have been successfully synthesized using MAOS (Microwave-Assisted Organic Synthesis) method. These ionic liquids were synthesized by reacting 1-methylimidazole with n-bromodecane and n-bromododecane, respectively. The synthesized products were purified by extraction and vacuum distillation. The synthesized products then characterized using TLC (Thin Layer Chromatography), as well as 1H-NMR, and 13C-NMR spectroscopy. The yields for the ionic liquids [DMIm]Br and [DDMIm]Br were 34.22% and 45.57%, respectively. The conductivity of these ionic liquids was tested using electrochemical impedance spectroscopy method and electrochemical window width test using cyclic voltammetry method for its application as electrolyte solvent in Li-ion batteries. Measurement result found that electrochemical window width of [DDMIm]Br and [DMIm]Br was 1,02 V and 0,56 V, respectively. It was also found that the conductivity of [DMIm]Br was much greater than [DDMIm]Br which indicates that with increasing alkyl chain length, its electrochemical stability increased and its conductivity decreased. Computational calculation using DFT method (Density Functional Theory) at B3LYP theory level and 6-31G (d,p) basis set showed that from 3 variations of cations, namely [OMIm]+ (1-octyl-3-methylimidazolium), [DMIm]+, and [DDMIm]+, the length of the alkyl chain does not really affect the width of electrochemical window, while from 3 variations of anions, namely [BF4]?? [PF6]?, and [TFSI]?, shows that the width of electrochemical window is very much influenced by the anion type with the order is as follows: [PF6]? > [BF4]? > [TFSI]?.