Solid polymer electrolytes. XI. Preparation, characterization and ionic conductivity of new plasticized polymer electrolytes based on chemical‐covalent polyether–siloxane hybrids

Abstract

ABSTRACT:A new hybrid polymer electrolyte system based on chemical-covalent polyether and siloxane phases is designed and prepared via the sol-gel approach and epoxide crosslinking. FT-IR, 13 C solid-state NMR, and thermal analysis (differential scanning calorimetry (DSC) and TGA) are used to characterize the structure of these hybrids. These hybrid films are immersed into the liquid electrolyte (1M LiClO 4 /propylene carbonate) to form plasticized polymer electrolytes. The effects of hybrid composition, liquid electrolyte content, and temperature on the ionic conductivity of hybrid electrolytes are investigated and discussed. DSC traces demonstrate the presence of two second-order transitions for all the samples and show a significant change in the thermal events with the amount of absorbed LiClO 4 /PC content. TGA results indicate these hybrid networks with excellent thermal stability. The EDS-0.5 sample with a 75 wt % liquid electrolyte exhibits the ionic conductivity of 5.3 ϫ 10 Ϫ3 S cm Ϫ1 at 95°C and 1.4 ϫ 10 Ϫ3 S cm Ϫ1 at 15°C, in which the film shows homogenous and good mechanical strength as well as good chemical stability. In the plot of ionic conductivity and composition for these hybrids containing 45 wt % liquid electrolyte, the conductivity shows a maximum value corresponding to the sample with the weight ratio of GPTMS/PEGDE of 0.1. These obtained results are correlated and used to interpret the ion conduction behavior within the hybrid networks.

Organosilicon‐Based Functional Electrolytes for High‐Performance Lithium Batteries

“…[ 132,133 ] Recently, organosilicon‐functionalized PEO has been evaluated as a reliable electrolyte owing to higher flashpoint, lower vapor pressure, better ionic conductivity, wider operating voltage, and higher thermal stability than pristine PEO and the traditional alkylcarbonates. [ 51,134–138 ] The performance improvement after functionalization originates from the finely tuned interactions among PEO, alkali salt and organosilicon, and the particular characteristics of organosilicon. For example, the integration of organosilicon reduces the T g of PEO, whose ion transport is thus effectively promoted due to improved segmental mobility.…”

Correlations of Ion Motion and Chain Motion in Salt-in-Polysiloxane-g-oligoether Electrolytes

“…14−17 A valuable tool is the combination of investigations with multinuclear NMR and impedance spectroscopy. 18,19 In general, in poly(ethylene oxide) or oligoether-containing polymer systems the coordination of Li to the ether oxygens is essential, as it promotes salt dissociation. However, at the same time the coordination also limits the Li mobility and transference numbers are typically larger for the anion than for Li + .…”

“…Apart from material optimization based on conductivity data, an advanced understanding of the transport mechanisms in such systems is essential for performance improvement. However, not many investigations have dealt with characterizing ion transport in polysiloxane based polymer electrolytes. − A valuable tool is the combination of investigations with multinuclear NMR and impedance spectroscopy. , …”

Novel nanocomposite of poly(acrylonitrile‐co‐glycidyl methacrylate) crosslinked with Jeffamine‐functionalized multiwalled carbon nanotubes as gel polymer electrolytes

“…Generally, the used fillers are inert and nonconductive. Chemical crosslinking modification with the formation of covalent bonds is another important means for the improvement of the mechanical properties of GPEs 16, 17. The resulting crosslinked nanocomposite polymer electrolytes exhibit significantly higher elastic modulus and yield stress than their physically formed nanocomposite counterpart at the cost of negligible loss in transport properties 18…”