Browsing by Author "Sharma, A. L."

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Conductivity and stability properties of solid polymer electrolyte based on PEO-PAN + LiPF 6 for energy storage
(Applied SCience Letters, 2016) Arya, Anil; Sharma, A. L.
Ionically conducting solid polymer electrolyte (SPE) films has drawn considerable attention because of its many appealing properties such as flexibility, design mouldability, role as leakage free solid separator/electrolyte in devices and improved safety hazard. Polymer blend electrolytes are prepared for various concentration of salt ( ) with the constant ratio (0.5 gm) of each PEO and PAN polymers (blend polymer) using solution casting technique. The maximum ac ionic conductivity value is found to be of the order of ~10-5 S cm-1 for the film having = 4 support the applicability of films for the energy storage/conversion device application. The thermo gravimetric analysis (TGA) result shows the stability of the prepared films for use in the device application. Finally the cyclic voltammetry experiment was performed to see the voltage sustainability (~4 Volt) of prepared free standing solid polymeric films for the device applications.
Correlation of ion-ion interaction with electrical conductivity in solid state polymeric separator for energy storage applications
(American Institute of Physics Inc., 2016) Sharma, Parul Kumar; Sadiq, M.; Bhatt, Chandni; Sharma, A. L.
In the present study, we report innovative study on the prepared high quality solid state free standing thin polymeric separator. In prepared free standing polymeric separator, polymer (PEO) has been used as host matrix; appropriate bulky anion salt (LiPF6) as conducting species and Nano ceramic filler (BaTiO3) is used to enrich the mechanical and thermal stability of separator used for the device applications. The Fourier Transform Infra-Red (FTIR) result has been analysed properly of the prepared materials to look the microscopic interaction among polymer-ion, ion-ion and polymer-ion-clay interaction. Electrical conductivity results has been recorded using the impedance spectroscopy results which gives the estimated value of the order of ?10-3 Scm-1 of the nano ceramic doped polymeric separator which is desirable for energy storage application. A fine correlation has been established between the obtained results by this two analysis. ? 2016 Author(s).
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.
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.
Effect Of MWCNT On Prepared Cathode Material (Li 2 Mn (x) Fe (1-x) SiO 4 ) For Energy Storage Applications
(AIP Publishing, 2016) Agnihotri, Shruti; Rattan, Sangeeta; Sharma, A. L.
The electrode material Li 2 MnFeSiO 4 was successfully synthesized by standard sol–gel method and further modified with multiwalled carbon nano tube (MWCNT) to achieve better electrochemical properties. Our strategy helps us to improve the performance and storage capacity as compared with the bared material. This novel composite structure constructs an efficient cation (Li + ) and electron channel which significantly enhance the Li + ion diffusion coefficient and reduced charge transfer resistance. Hence leads to high conductivity and specific capacity. Characterization technique like Field emission scanning electron microscopy (FESEM) has been used to confirm its morphology, structure and particle size which comes out to be of the order of ~ 20 to 30 nm. Lesser particle size reveals better electrochemical properties. Electrical conductivity (~10 -5 Scm -1 ) of MWCNT doped oxide cathode materials was recorded using ac impedance spectroscopy technique which reflects tenfold increment when compared with pure oxide cathode materials. Cyclic voltametery analysis has been done to calculate specific capacity and potential window of materials with and without CNTs. The results obtained from different techniques are well correlated and suitable for energy storage applications.
Effect of Nano filler on PEO based polymer electrolytes for energy storage devices applications
(Intergated Science, 2017) Sharma, P. K.; Sharma, A. K.; Sadiq, M.; Sharma, A. L.
Ionically conducting solid polymer films have been utilized in many energy related sectors like high energy density solid polymer batteries, PEM fuel cells, and super capacitors, etc.In the present study, we report innovative study on the prepared high quality solid state free standing thin polymeric separator. In prepared free standing polymeric separator, polymer (PEO) has been used as host matrix; appropriate bulky anion salt (NaClO 4 ) as conducting species and nano ceramic filler (BaTiO 3 ) is used to enrich the mechanical and thermal stability of separator used for the device applications. The Fourier Transform Infra-Red (FTIR) result has been analysed properly of the prepared materials to look the microscopic interaction among polymer-ion, ion-ion and polymer-ion-filler interaction. Electrical conductivity results has been recorded using the impedance spectroscopy results which gives the estimated value of the order of ~10 Scm of the nano ceramic doped polymeric separator which is desirable for energy storage application. A fine correlation has been established between the electrical conductivity and FTIR results analysis
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.
Electrical Conductivity and Ion Transport Number Analysis of Polymer Nanocomposite Films
(The Research Publication, 2016) Sharma, Parul Kumar; Sharma, Anshu Kumar; Sadiq, M.; Sharma, A. L.
Solid state free standing polymer nanocomposite films have been used in numerous vitality related segments like: high energy density solid polymer batteries, PEM fuel cells, super capacitors, etc. Such applications require a desirable conductivity value of the order of ~10-3 Scm-1at room temperature. A free standing transparent film of solid state polymer electrolyte based on PEO+ LiPF6 with different compositions of nano sized filler (BaTiO3) in weight percent (x = 0, 1, 2, 5, 10, 15, 20 ) is synthesized by using standard solution cast technique. Surface morphology of the prepared polymer composition is examined by field emission scanning electron microscopy (FESEM). I-V characteristics of the prepared sample have been characterized for the stability of electrochemical potential window. The transport number analysis of prepared sample has been done to separate out the contribution due to ions and electrons in the electrical conductivity results. The transference number has been estimated and found of the order of ~94%.
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.
Improved electrical properties of free standing blend polymer for renewable energy resources
(American Institute of Physics Inc., 2016) Arya, Anil; Sharma, Sweety; Sharma, A. L.
Blend polymer electrolytes are prepared for salt concentration (?/Li = 4) with the constant ratio (0.5 gm) of PEO and PAN using solution casting technique. The prepared free standing solid polymeric film is characterized by Field Emission Scanning Electron Microscopy (FESEM) which confirms the homogeneous distribution of dissociated salt in blend polymer matrix. After addition of salt the ionic conductivity value is found to be of the order of 7.13 ? 10-5 Scm-1 which is three orders higher when compared with pure blend polymer films. The microscopic interaction among the polymer-ion, ion-ion has been confirmed by the Fourier Transform Infrared (FTIR) Spectroscopy. A very fine correlation has been built in the electrical conductivity and FTIR result. On the basis of above finding, a prepared free standing solid polymeric film appears to be appropriate for the energy storage/conversion device applications. ? 2016 Author(s).
Improved electrochemical performance of the Cr doped cathode materials for energy storage/conversion devices
(American Institute of Physics Inc., 2016) Agnihotri, Sangeeta Shruti; Arya, Anil; Sharma, A. L.; Sangeeta, S.
Successful synthesis of a nanostructured Cr-doped LiFePO4 cathode material has been prepared by a sol-gel technique followed by a single step thermal treatment at 750? C for 12 hours. As olivine type LiFePO4 has already gained much attention due to its advantages over other cathode materials, doping of metal ion is done in the paper to improve its drawback of lower conductivity. FESEM couples with EDX were done to characterize the morphology and particle size of the materials. LiFe(1-x)CrxPO4 (x=0.1, 0.2, 0.3) materials have average particle size of 30 to 50?nm. EDX analysis confirmed the precursor used and also confirmed the presence of carbon which is in good agreement with chemical analysis result. Electrical conductivity of the prepared cathode materials is estimated of the order of 10-5 Scm-1 by AC impedance analysis. The energy density and power density of the cathode materials is improved drastically after addition of Cr as dopant. The estimated parameters appear at desirable value for use of materials as cathode in energy storage/conversion devices. ? 2016 Author(s).
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).
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.
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.
Optimization of salt concentration in polymer based ionic conductor
(American Institute of Physics Inc., 2017) Thakur, Deep Kumar; Sharma, A. L.
Free standing polymeric films (electrolytes) have been prepared by PAN as a polymer host and Li salt (LiPF6) using the standard solution cast process. Interaction of polymer-salt complex of the host matrix has also been observed in the Fourier transform infrared (FTIR) spectrum results. The cation (Li+) coordination at nitrile (-C?N) site of the polymer backbone along with the appearance of a shoulder suggesting strong evidence of polymer-ion interaction. Field Emission Scanning Electron Microscopy (FESEM), was used to study morphological information of grain boundaries and cracks while Complex impedance spectroscopy suggests bulk electrical conduction. Solid electrolytes provide advantages in terms of simplicity of design and operational safety, but typically SPE's have the conductivities that are lower than those of organic liquid electrolytes. ? 2017 Author(s).
Polymer electrolytes for lithium ion batteries: a critical study
(Institute for Ionics, 2017) Arya, A.; Sharma, A. L.
Polymer electrolytes (PEs) are an essential component being used in most energy storage/conversion devices. The present review article on a brief history, advantage, and their brief application of polymer electrolyte systems. It consists of a glimpse on liquid, gel, and solid polymer electrolyte and a contrast comparison concerning benefits/disadvantages among the three. The article started with a brief introduction of polymer electrolytes followed by their varieties and extreme uses. The role of host polymer matrix by taking numerous examples of polymer electrolyte published by the different renowned group of the concerned field has been explored. The criteria for selection of appropriate host polymer, salt, inorganic filler/clay, and aprotic solvents to be used in polymer electrolyte have been discussed in detail. The mostly used polymer, salt, solvents, and inorganic filler/clay list has been prepared in order to keep the data bank at one place for new researchers. This article comprises different methodologies for the preparation of polymer electrolyte films. The different self-proposed mechanisms (like VTF, WLF, free volume theory, dispersed/intercalated mechanisms, etc.) have been discussed in order to explain the lithium ion conduction in polymer electrolyte systems. A numerous characterization techniques and their resulting analysis have been summarized from the different published reports at one place for better awareness of the scientific community/reader of the area. ? 2017, Springer-Verlag Berlin Heidelberg.
Relaxation behavior in clay-reinforced polymer nanocomposites
(Institute for Ionics, 2015) Sharma, A.L.; Thakur, A.K.; Sharma, A. L.
The effect of clay reinforcement on dielectric, conductivity, and mechanical relaxation behavior of a polymer clay nanocomposite film is reported. Polymer nanocomposite is composed of three component polymers (polyacrylonitrile) as a host matrix, salt (LiPF6) as conducting species, and clay (sodium montmorillonite) as intercalant. The macroscopic parameters like polymer glass transition temperature and available free mobile charge carriers have been analyzed properly using dynamic mechanical analysis and dielectric analysis. Dielectric analysis indicated distribution of relaxation time as a function of clay concentration, whereas conductivity spectrum exhibited dispersion at lower frequency followed by saturation region at intermediate frequency. The dispersion behavior is related to the electrode polarization attributed to faster ion dynamics. The dielectric and conductivity relaxation are in excellent correlation with mechanical relaxation owing to the changes in glass transition temperature due to polymer-ion-clay interaction. The proposed mechanism is a sequel to the experimental results. ? 2014, Springer-Verlag Berlin Heidelberg.
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.
Role of salt concentration in blend polymer for energy storage conversion devices
(American Institute of Physics Inc., 2016) Arya, A.; Sadiq, M.; Sharma, A. L.
Solid Polymer Electrolytes (SPE) are materials of considerable interest worldwide, which serves dual purpose of electrolyte and separator between electrode compartments in renewable energy conversion/storage devices such as; high energy density batteries, electrochromic display devices, and supercapacitors. Polymer blend electrolytes are prepared for various concentration of salt (?/Li) with the constant ratio (0.5 gm) of each PEO and PAN polymers (blend polymer) using solution casting technique. Solid polymeric ionic conductor as a separator is the ultimate substitute to eliminate the drawback related to liquid and gel polymer ionic conductors. In the present work, solid polymer electrolyte film consisting of PEO, PAN and LiPF6 are examined for various concentration of lithium salt by keeping PEO/PAN blend ratio as a constant with a view to optimize the dominant salt concentration which could give the maximum conductivity at ambient temperature. ? 2016 Author(s).
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 applications