Influence of tetraglyme towards magnesium salt dissociation in solid polymer electrolyte for electric double layer capacitor

Abstract

Most of commercialized electrical double layer capacitors (EDLCs) with liquid electrolyte are bulky, non-flexible and unsafe which require solid polymer electrolyte (SPE) as the replacement. Herein, SPE containing tetraglyme as the ionic conductivity booster was prepared in which polyvinyl alcohol (PVA), magnesium trifluoromethane sulfonate (Mg (Tf)2) and tetraglyme (TEDGME) have been utilized as the host polymer, salt and additive, respectively. After the addition of TEDGME, the SPE exhibited a significant boost in ionic conductivity from 1.43 × 10−9 to 3.10 × 10−5 S cm−1. This is attributed to the presence of multiple ether oxygen atom functional group from TEDGME that provides more charge carriers. Fourier transform infrared spectroscopy authenticates the formation of complex within the SPE systems which indicates the formation of good interaction between the host polymer and the salts. X-ray diffraction analysis demonstrates the reduction in crystallinity of the SPE after the addition of TEDGME which is beneficial for the ion diffusion. The maximum specific capacitance achieved by the EDLC employing the SPE incorporated with TEDGME is 6.34 F/g at 0.04 A/g, with the rate capability of 74.1%.