Thermal, Conductivity and Molecular Interaction Studies of Poly(ethylene oxide)/Poly(methyl acrylate) Solid Polymer Electrolytes

Abstract

Summary Solid polymer electrolytes of poly(ethylene oxide) (PEO) and poly(methyl acrylate) (PMA) with addition of lithium perchlorate (LiClO4) were studied. Samples were prepared by solution casting method. An existence of single and compositional‐dependant glass transition temperature (Tg) of PEO/PMA systems [studied by Differential scanning calorimetry (DSC)] shows miscibility of the binary PEO/PMA blends as well as when added with small of amount of LiClO4 in the molten state and amorphous phase. The systems are miscible in molten state and amorphous phase at high salt content with PEO content in the blends is in excess. In this case, the Tgs of the PEO/PMA blends increase slightly with increasing salt concentration suggesting the molecular interaction of salt with the polymers. Impedance spectroscopy (IS) studies reveal that PEO/PMA 80/20 blend (w/w) added with 0.12 of LiClO4 (YS) shows the highest conductivity (σDC = 1.43 × 10−5 S cm−1) as compared to PEO/LiClO4 system at the same salt concentration (σDC = 6.43 ×10−6 S cm−1). Results of Tg using DSC and molecular interaction from Fourier‐transform infrared (FTIR) spectra suggest that blend with PEO in excess, Li+ ions coordinate with ether oxygen of PEO instead of carbonyl oxygen of PMA. Hence, the percolation pathway for these SPEs is lying in the amorphous region of the PEO phase.

Thermal Properties and Morphology of Poly(ethylene oxide)/Poly(n‐butyl methacrylate) Blends

“…However, the binary systems of PEO and salt display low conductivity ( σ DC ∼10 −6 –10 −8 S cm −1 ) and show higher conductivity ( σ DC ∼10 −4 S cm −1 ) above its melting temperature at around 65 °C and hence, they are not suitable for the commercial application at ambient temperature. This is due to the high crystallinity (up to 70%) for high molar‐mass SPEs . Thus, various approaches have been made to enhance to conductivity of SPEs such as addition of plasticizers and fillers, polymer blending, polymer hosts using copolymers etc.…”

“…Hence, the demand for rechargeable power sources is now focusing on solvent-free polymer electrolytes, which have been attaining great research attention both academically and industrially over the last two decades. [1][2][3][4][5][6][7] Solid polymer electrolytes (SPEs) (the solvent-free polymer electrolytes) based on poly(ethylene oxide) (PEO) as a polymer host have been extensively studied, [6,[8][9][10][11][12] due to its high solvating capability of wide variety of metallic salts such as lithium sulfate (Li 2 SO 4 ), [13,14] lithium iodide (LiI), [15,16] lithium triflate (LiCF 3 SO 3 ), [13,17,18] lithium bis(fluorosulfonyl)imide (LiFSI), [19,20] lithium perchlorate (LiClO 4 ) [21][22][23] and lithium tetrafluoroborate (LiBF 4 ). [24,25] However, the binary systems of PEO and salt display low conductivity (σ DC $10 À6 -10 À8 S cm À1 ) [4,[26][27][28] and show higher conductivity (σ DC $10 À4 S cm À1 ) above its melting temperature at around 65 C [8,29] and hence, they are not suitable for the commercial application at ambient temperature.…”

“…This is due to the high crystallinity (up to 70%) for high molar-mass SPEs. [5][6][7]18,30] Thus, various approaches have been made to enhance to conductivity of SPEs such as addition of plasticizers [31][32][33] and fillers, [34][35][36][37][38][39][40] polymer blending, [4,26,[41][42][43] polymer hosts using copolymers [44][45][46][47][48] etc. Blending PEO with another component is one of the cost-effective and convenient ways for the enhancement of the conductivity of SPEs by compositional change of the blends.…”

“…is getting higher nowadays. Hence, the demand for rechargeable power sources is now focusing on solvent‐free polymer electrolytes, which have been attaining great research attention both academically and industrially over the last two decades . Solid polymer electrolytes (SPEs) (the solvent‐free polymer electrolytes) based on poly(ethylene oxide) (PEO) as a polymer host have been extensively studied, due to its high solvating capability of wide variety of metallic salts such as lithium sulfate (Li 2 SO 4 ), lithium iodide (LiI), lithium triflate (LiCF 3 SO 3 ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium perchlorate (LiClO 4 ) and lithium tetrafluoroborate (LiBF 4 ) .…”

Quo Vadis, Macromolecular Science? Reflections by the IUPAC Polymer Division on the Occasion of the Staudinger Centenary

“…[74,75] High ionic conductivity coexisting with high lithium ion transference number may lead to a reduction of polarization (resistance), and hence electrical performance can be enhanced. [76] Various strategies for polymer hosts have been introduced to improve the electrical properties of the SPEs, e. g. polymer-blends, [76][77][78][79][80] addition of fillers (e. g. Al 2 O 3 , TiO 2 ), [74,75,81,82] addition of plasticizers, [83][84][85] tuning macromolecular architectures (e. g. block copolymers, [86][87][88] graft copolymers, [89][90][91] polymer networks [92][93][94] ), or a combination of these strategies. [95][96][97] Efficient energy storage is the prerequisite for the switch from fossil fuels to electrically-powered vehicles, and discovery of new anode materials, cathode materials and electrolytes is anticipated for sustainable battery technology.…”