Department Of Physics
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Item Improved ionic conductivity, potential window and dielectric strength in intercalated polymer nanocomposites(American Institute of Physics, 2019) Pritam, Arya A; Sharma, A. L.A nanocomposite solid polymer electrolyte has been synthesized using polyethylene oxide (PEO), sodium hexafluorophosphate (NaPF6), and organomodified montmorillonite (DMMT) nano-clay, with an aim to improve the ionic conductivity, voltage stability window, transference number and dielectric properties. The DMMT intercalated PNCs exhibits an ionic conductivity of three order (∼10-5 S cm-1) higher as compared to the pure polymer (∼10-8 S cm-1). The DMMT based PNCs have ion transference number close to unity (0.99) and wide voltage stability window (∼5V). The dielectric constant and dc conductivity increases with nanoclay addition. The relaxation peak in loss tangent plot shift toward high frequency on nanoclay addition and indicates the decrease of relaxation time. The evaluated relaxation time τϵ′, τtan δ, τh, τm are in good correlation with each other and exhibits minima for the nanoclay based PNCs which infers the faster segmental motion of polymer chain and supports the enhanced ionic conductivity. © 2019 Author(s).Item Effect of Nano-Filler on the Properties of Polymer Nanocomposite Films of PEO/PAN Complexed with NaPF 6(Journal of Materials Science and Engineering B 5, 2016) Bhatt, Chandni; Swaroop, Ram; Arya, Anil; Sharma, A. L.Free standing transparent PNC (Polymer nanocomposite) films based on PEO/PAN + NaPF 6 with different concentration (wt./wt.) filler of nano sized (TiO 2 ) is synthesized by using standard solution cast technique. HRXRD (High resolution X -ray diffraction) and FESEM (Field emission scanning electron microscopy) have been performed to see the structural and microstructural behavior of the PNC films. The microscopic interaction among polymer, salt and nano-ceramic filler has been analyzed by FTIR (Fourier transformed infra-red) spectroscopy. The reduction of ion pair formation in polymeric separator is clearly observed on addition of nano-filler in the polymer salt complex film. Electrical (ionic/electronic) conductivity has been estimated (~ 10 -4 S/cm) optimized PNC films concentration of nanofiller (15 Wt.%). The estimated value of electrical conductivity is well corroborated by FTIR study. Thermal analysis has been done with thermo gravimetry analysis to find out thermal stability of PNC films. Transport properties associated due to majority mobile carriers ions and only negligible participation from electrons was observed through transport number analysis. The band gap (i.e. direct as well as indirect) decreases on the addition of nano-filler observed from the optical analysis. The estimated result of the prepared PNC films are at par with desired value for the device application.Item Sodium-Ion-Conducting Polymer Nanocomposite Electrolyte of TiO 2 /PEO/PAN Complexed with NaPF 6(AIP Publishing, 2016) Bhatt, Chandni; Swaroop, Ram; Sharma, Parul Kumar; Sharma, A. L.A free standing transparent of state based on PEO/PAN+NaPF6 with different compositions of nano sized TiO2 in weight percent (x = 0, 1, 2, 5, 10, 15, 20) is synthesized by using standard cast technique. The homogeneous of above composition is examined by FESEM. The microscopic interaction among salt and nanoceramic filler has been analyzed by Fourier Transformed Infra-Red spectroscopy. The reduction of ion pair formation in polymeric separator is clearly observed on addition of nanofiller in the salt complex Electrical conductivity has been recorded of the prepared polymeric separator which is of the order of ∼10−4 Scm−1 after addition of nanofiller (15% wt/wt) which support the results. Electrochemical potential window has been observed of the order of ∼6V by the cyclic voltammetry results. The observed data of the prepared separator are at par with the desirable value for device applicationsItem Development of novel cathode materials based on MWCNT for energy storage/conversion devices(Springer Science and Business Media, LLC, 2017) Agnihotri, Shruti; Rattan, Sangeeta; Sharma, A. L.In Chap. 1, already available technology for energy storage solutions like capacitors, lead acid batteries, compressed air energy storage, flywheels has been discussed in order to compare their energy and power densities. Emphasis has been laid on Rechargeable Lithium ion Battery (Li-ion). Various materials which are already explored and used as cathode of battery has also been discussed with their merits and demerits. Further introduction of prepared orthosilicate material with used conductive additive Multiwalled carbon nano tube (MWCNT) has also given. In Chap. 2, methodology used to prepare respective Li2MnFeSiO4 material and its composite with MWCNT has been discussed in detail. Further, in order to validate its electrochemical application, different steps of cell assembly of Lithium half cell fabrication has also been discussed. Chapter 3 comprises of results obtained using standard Field emission scanning electron microscope (FESEM). Effect of used MWCNT on its morphology has been discussed in this chapter. A.C Impedance spectroscopy has been used to study variation in conductivity with respect to bared material. Possible reasons for increased conductivity with morphology has also been discussed in discussion. Chapter 4 includes conclusions drawn from mentioned results. This chapter summarizes measured conductivity values with different concentrations of MWCNT. Improved conductivity with respect to bared orthosilicate material has been pointed in this chapter. ? Springer International Publishing Switzerland 2017.Item Correlation of microscopic interaction with electrical conductivity in polymer separator of energy storage devices(Springer Science and Business Media, LLC, 2017) Sharma, Parul Kumar; Sharma, Anshul Kumar; Sadiq, M.; Sharma, A. L.In the present report solid polymer nanocomposite (PNCs) comprising of (PEO)14+ NaClO4+ wt% BaTiO3has been prepared by solution casting method. Important characterization like: FTIR (Fourier Transform Infrared Spectroscopy), and conductivity have been performed for the applicability of the prepared materials in device application. The highest conductivity of the prepared polymer nanocomposite materials has been estimated 1?10?4Scm?1for 15 wt% of BaTiO3. A very fine correlation has been built among polymer-ion, ion-ion and polymer ion interaction with obtained conductivity results. ? Springer International Publishing Switzerland 2017.Item Evaluation of aluminium doped lanthanum ferrite based electrodes for supercapacitor design(Elsevier, 2014) Rai, Atma; Sharma, A. L.; Thakur, Awalendra K.; Thakur, A.K.We report Al doped ferrites La1 - xAlxFeO 3(x = 0, 0.3) as an electrode material for supercapacitor design. The La1 - xAlxFeO3 has been synthesized via chemical route. Structural and microstructural evolution has been carried out by X-ray diffraction (XRD) analysis and field emission scanning electron microscopy (FESEM) respectively. The electrode property of La 1 - xAlxFeO3 has been evaluated by using three electrode systems, glassy carbon (working), Pt (counter) and Ag/AgCl (reference electrode) with H2SO4 as the electrolyte. The Al doped ferrites show better cycle life (~ 250) and columbic efficiency (?) (~ 96%) in comparison to un-doped lanthanum ferrite sample. An increase in specific capacitance (~ 1.5 times) has also been observed in Al doped lanthanum ferrite in comparison to lanthanum ferrite. The maximum specific capacitance for Al doped lanthanum ferrite is ~ 260 F/g as compared to lanthanum ferrite ~ 200 F/g. The improved specific capacitance, columbic efficiency and cycle life of Al doped ferrites may be related to a relative decrease in equivalent series resistance (95 ? for LFO to 55 ? LAFO) and lower M.W. of Al doped lanthanum ferrite. ? 2013 Elsevier B.V.Item Transport Properties of Solid Polymer Nanocomposite Films for Energy Device Applications(NIT Srinagar, 2016) Sadiq, M.; Sharma, A. L.Sample preparation of high quality new series polymer nanocomposite (PNC) films based on (PAN-PEO)-LiPF 6 +xwt. %DMMT has been prepared via solution cast technique. Keeping in view of applications of solid state PNC films, Fourier transform infrared (FTIR) spectroscopy is done for understanding of microscopic interaction among the different composite component present in the material system. The impedance and electrochemical analysis have been done to fulfill the objective of the materials for the energy storage/conversion device applications. Thermo gravimetric analysis (TGA) has been done to estimate the thermal stability of the prepared polymer nanocomposite films.Item Optimization of concentration of MWCNT in terms of performance of prepared novel cathode material for energy storage(Integrated Science, 2017) Agnihotri, Shruti; Sharma, A. L.The successful synthesis of a novel cathode material Li2MnFeSiO4 (LMFS) was done using thestandardSol-Gel technique. To improve the electrical conductivity of cathode material different concentration (wt/wt) of MWCNT are incorporated into LMFS generating composite Li2MnFeSiO4/MWCNT via solution method. In order to achieve better electron passage to particle–particle boundaries, MWCNT is considered as one of the ideals and appropriate conductive additive. The Li2MnFeSiO4 nanoparticles are dispersed homogeneously in CNT's network and assembled as micro-sized porous spherical particles. Such special composite structure constructs an efficient Li+ and electron channel, which significantly enhance the Li-ion diffusion coefficient and reduced the charge transfer resistance, hence may lead to high electrical conductivity. Carbon nano tube not only deposited on the surface, but also provide theinterconnected network. This continuous conductive network enhances the electronic conductivity of the insertion/de-insertion cycles. Complex impedance spectroscopy (EIS) is used to estimate the electrical conductivity of prepared samples. The Li2MnFeSiO4/MWCNT with 12 wt% of CNT delivers highest electrical conductivity (i.e. ~10-3 Scm-1) which is at par with desire for the energy storage applications.Item Role of low salt concentration on electrical conductivity in blend polymeric films(Integrated Science, 2016) Arya, Anil; Sharma, Sweety; Sadiq, Mohd; Sharma, A. L.A new blend polymer electrolyte based on polyethyelene oxide (PEO) and polyacrylonitrile (PAN) doped with Lithium Hexafluorophosphate (LiPF6) has been prepared by solution casting technique using Dimethyalformamide (DMF) as solvent. The prepared samples were characterized by FTIR, FESEM and ac impedance spectroscopic measurements. The complex formation between blend polymer (0.5g PEO: 0.5g PAN) and LiPF6 has been studied using Fourier transform infrared spectroscopy (FTIR). From AC impedance spectroscopic analysis there is enhancement of two order on addition of salt than pure PEO-PAN. The effect of low salt concentration on the conductivity and surface morphology of the blend polymer electrolyte has been discussed.Item Optimization of Free standing Polymer Electrolytes films for Lithium ion batteries application(Integrated Science, 2016) Sadiq, M.; Arya, Anil; Sharma, A. L.The free standing polymer nancomposite films consisting of blend polymer based on Poly(acrylonitrile) (PAN) as host polymer–Poly(ethylene oxide)(PEO) as a copolymer, Dimethylformamide (DMF) as solvent and Lithium hexaflourophosphate (LIPF6) as a conducting speciesm were prepared. Keeping in view of characterization of solid state film such as, Fourier transform infrared (FTIR) spectroscopy is done for an understanding of the microscopic interaction among the different component present in the material system. The energy storage/conversion device applications have been analyzed by the impedances spectroscopy. The surface morphology or micro-structural of the polymer nanocomposite electrolytes film was analyzed by FESEM. The electrochemical stability window was about ~4V for the polymer electrolyte film at (/Li=6). The advantageous outcome of PAN combining with PEO based electrolytes is in comparable electrical conductivity and wider electrochemical stability window. Further optimization might lead to practical solid state polymer electrolytes for lithium ion batteries.
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