Dynamic Mechanical, DSC, and Electrical Investigations on Nano Al₂O₃Filled PVA:NH₄SCN:DMSO Polymer Composite Dried Gel Electrolytes

Abstract

This paper reports the dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and ionic conductivity studies on nanosized Al 2 O 3 (aluminium oxide) filled PVA:NH 4 SCN:DMSO polymer composite dried gel electrolytes prepared by the wet chemistry route. Better mechanical stability and thermal behavior are noticed in the composite system. Multiple relaxation peaks seen in tangent loss measurements (in DMA studies) have been suitably correlated. Enhancement in ionic conductivity has been noticed with an optimum value of 4.02 Â 10 À3 Scm À1 for 4 wt% nano Al 2 O 3 filled composite electrolytes. Temperature dependence of ionic conductivity shows a combination of Arrhenius and VTF (Vogel-Tamman-Fulcher) behavior.

DMA and Conductivity Studies in PVA:NH4SCN:DMSO:MWNT Nanocomposite Polymer Dried Gel Electrolytes

“…Further, a small shoulder around 98 ∘ C has been traced in E . This can be correlated to presence of water formed in the process of interaction of DMSO with PVA and has been reported earlier [11]. This transition shifts on temperature scale towards lower temperature with increase of MWNT contents ( Table 1).…”

“…Pure PVA powder used in the present investigation possesses a glass transition of nearly ∼85 ∘ C and has been reported in one of our earlier papers [8]. This transition shifts towards higher temperature in nanocomposite polymer electrolyte with MWNT level upto 4 wt% and transforms into welldefined broad peak in E & tan reflecting dynamic of PVA in NCPE and also referred as a relaxation [11]. Further, a small shoulder around 98 ∘ C has been traced in E .…”

“…The loss spectra of pristine complex show a well-defined peak around 120 ∘ C. This can be assigned to presence of bound water in pristine system. Existence of this water has also been shown earlier [11]. A shoulder relaxation around 150 ∘ C gives reflection of the presence of uncomplexed salt in electrolyte on account of melting of salt [12].…”

“…At intermediate concentrations the decrease in conductivity may be due to pairing effect/re-association of free ions [1,5,21]. The second conductivity maxima is related to formation of highly conducting interfacial layer between MWNT and gel electrolyte caused by filler salt interaction which dominates over ion pairing effect [6,11,14,24]. Ionic conductivity of polymer electrolytes is known to augment with rise of temperature and the behaviour has been rationalised by recognizing free volume model [30].…”

“…After the advent of nanotechnology, researchers have also used dispersion of a third component of nanodimensions in pristine polymer electrolytes in a bid to circumvent problems cited above. Thus, efforts have been directed in recent past to develop high performance nanocomposite polymer electrolytes [11,12]. Generally, nanostructural particles like ceramics [12,13] and carbon nanotubes [14] have not only been shown to improve the mechanical properties of gel and solid polymer electrolyte membranes and their nanofibers but they have also provided improved conductivities to allow their usage in sensors, super capacitors, batteries, electronic components, and so forth [15].…”