Green Synthesis of [EMIm]Ac Ionic Liquid for Plasticizing MC-based Biopolymer Electrolyte Membranes

Abstract

Lithium-ion batteries (LIBs) are favorable power source devices in recent years, due to their high energy density, rechargeable, long life cycle, portable, safe, rechargeable, good performances and environmentally friendly. To support the LIBs development, in this research, we have successfully prepared the biopolymer electrolyte membranes based on 1-ethyl-3-methylimidazolium acetate, [EMIm]Ac, ionic liquid-plasticized methyl cellulose/lithium perchlorate (MC/LiClO₄). [EMIm]Ac ionic liquid was easily synthesized by metathesis reaction between 1-ethyl-3-methylimidazolium bromide,    [EMIm]Br, ionic liquid and potassium acetate (CH₃COOK) at ambient temperature, for 1 hour. The functional groups within the structure of [EMIm]Ac was analyzed using Fourier Transform Infra-red (FTIR) spectroscopy and its structure was further analyzed using ¹H-NMR and ¹³C-NMR spectroscopy. The [EMIm]Ac-plasticized MC/LiClO₄ biopolymer electrolyte membranes were prepared by casting solutions, with various [EMIm]Ac ionic liquid contents of 0, 5, 10, 15, 20, 25, and 30% (w/w).  The effect of 15% (w/w) [EMIm]Ac ionic liquid incorporation to MC/LiClO₄ exhibited the best condition, and it was further selected as the optimum condition to reveal the ionic conductivity, tensile strength, elongation break and thermal stability properties, which are 9.16 x 10^-3 S.cm^-1, 24.19 MPa, 36.43%, ~256 and ~370 ^oC, respectively. These results confirmed that the [EMIm]Ac ionic liquid has capability to plasticize the MC/LiClO₄ biopolymer electrolyte membranes with outstanding performances that fulfill the LIBs’ separator requirement.

Keywords:  Biopolymer electrolytes, Cellulose; Ionic Liquids; Lithium-ion Batteries; Methyl cellulose.

Authors: Sun Theo Constan Lotebulo Ndruru¹, Deana Wahyuningrum², Bunbun Bundjali¹, I Made Arcana¹

¹ Inorganic and Physical Chemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia

² Organic Chemistry Division, Faculty of Mathematics and Natural Sciences, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132, Indonesia