Browsing by Author "Biswal, R."

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Comparative Studies on Crystalline and Amorphous Vinylidene Fluoride Based Fibrous Polymer Electrolytes for Sodium-Ion Batteries
(Springer Singapore, 2020) Janakiraman, S.; Khalifa, M.; Biswal, R.; Ghosh, S.; Anandhan, S.; Adyam, A.
In the present work, electrospun poly (vinylidene fluoride) (PVDF) and poly (vinylidene fluoride-co hexafluropropylene) (P(VdF-co-HFP)) fibrous membranes have been compared. Porous homo and copolymer fiber-based membranes with an interconnected structure, high porosity, large electrolyte uptake were prepared by an electrospinning route. The effect of crystallinity in terms of X-ray diffraction (XRD) was investigated for the fibrous polymer membranes (FPMs). The surface morphology of the FPMs is evaluated by field emission scanning electronmicroscopy (FESEM). The FPMswere soaked in 1MNaClO4-ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1, vol%) solution to form fibrous polymer electrolytes (FPEs). The ionic conductivity of copolymer showed 1.126 mS cm−1 under ambient temperature (at 28 °C) higher than the homopolymer (0.79 mS cm−1) because of HFP unit. The electrochemical stability window of the copolymer membrane also enhanced and stable up to 4.9 V versus Na+/Na suitable for high voltage sodium rechargeable batteries. When tested with Na066Fe0.5Mn05O2 as cathode and Na metal as an anode, the cycle performance significantly improved for the copolymer. © Springer Nature Singapore Pte Ltd. 2021.
Electrochemical characterization of a polar ?-phase poly (vinylidene fluoride) gel electrolyte in sodium ion cell
(2019) Janakiraman, S.; Surendran, A.; Biswal, R.; Ghosh, S.; Anandhan, S.; Venimadhav, A.
A polar ?-phase poly (vinylidene fluoride) (PVDF) membrane is developed through the electrospinning method. PVDF gel electrolyte for sodium ion batteries was obtained by saturating the bare porous membrane in a liquid electrolyte, 1 M NaClO4 in EC: DEC (1:1 vol%). The physical and electrochemical characteristics of the polar ?-phase PVDF membrane are explored by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Atomic force microscope (AFM), sodium ion conductivity, linear sweep voltammetry (LSV) and sodium ion transference number. The ionic conductivity of a polar ?-phase PVDF gel electrolyte exhibited 9.2 10?4 S cm?1, higher than the commercially used Celgard 2400 membrane 0.36 10?4 S cm?1 at ambient temperature. The electrochemical expolarations of the sodium ion half-cell (Na2/3Fe1/2Mn1/2O2) as a cathode and sodium metal as a counter electrode) conducted from PVDF gel electrolyte are analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV of the battery showed a pseudo capacitive nature. The equivalent circuit model of the sodium ion cell brought out the effect of dipole moments in the polymer chains on the battery performance. 2018 Elsevier B.V.
Electrochemical characterization of a polar ?-phase poly (vinylidene fluoride) gel electrolyte in sodium ion cell
(Elsevier B.V., 2019) Janakiraman, S.; Surendran, A.; Biswal, R.; Ghosh, S.; Anandhan, S.; Adyam, A.
A polar ?-phase poly (vinylidene fluoride) (PVDF) membrane is developed through the electrospinning method. PVDF gel electrolyte for sodium ion batteries was obtained by saturating the bare porous membrane in a liquid electrolyte, 1 M NaClO4 in EC: DEC (1:1 vol%). The physical and electrochemical characteristics of the polar ?-phase PVDF membrane are explored by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Atomic force microscope (AFM), sodium ion conductivity, linear sweep voltammetry (LSV) and sodium ion transference number. The ionic conductivity of a polar ?-phase PVDF gel electrolyte exhibited 9.2 × 10?4 S cm?1, higher than the commercially used Celgard® 2400 membrane 0.36 × 10?4 S cm?1 at ambient temperature. The electrochemical expolarations of the sodium ion half-cell (Na2/3Fe1/2Mn1/2O2) as a cathode and sodium metal as a counter electrode) conducted from PVDF gel electrolyte are analysed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV of the battery showed a pseudo capacitive nature. The equivalent circuit model of the sodium ion cell brought out the effect of dipole moments in the polymer chains on the battery performance. © 2018 Elsevier B.V.
Electrospun electroactive polyvinylidene fluoride-based fibrous polymer electrolyte for sodium ion batteries
(2019) Janakiraman, S.; Surendran, A.; Biswal, R.; Ghosh, S.; Anandhan, S.; Venimadhav, A.
Electrospinning is an efficient technique to produce ultrafine electroactive mat, diameters ranging from few nanometers to micrometers to use as a separator in sodium ion battery. The polyvinylidene fluoride (PVDF) polymer solution was optimized to 19 wt%, applied voltage 25 kV and flow rate of 0.5 ml h-1 to get a bead free ultrafine electroactive structure. The electroactive ?-phase is confirmed by x-ray diffractometer (XRD). Ionic conductivities, electrolyte uptake, wettability, linear sweep voltammetry (LSV) and thermal stability of the electroactive fibrous polymer electrolyte (EFPE) were studied by soaking the separator with a liquid electrolyte of 1 M sodium hexafluorophosphate (NaPF6) dissolved in ethylene carbonate (EC)/propylene carbonate (PC) (1:1 vol%). The EFPE exhibits high ionic conductivity of 1.08 mS cm-1 and electrochemical stability window of 5.0 V versus Na/Na+ under ambient condition. The half-cell containing Na0.66Fe0.5Mn0.5O2 as cathode and EFPE as the separator cum electrolyte showed a stable cycling performance at a current rate of 0.1C. 2019 IOP Publishing Ltd.
Electrospun electroactive polyvinylidene fluoride-based fibrous polymer electrolyte for sodium ion batteries
(Institute of Physics Publishing helen.craven@iop.org, 2019) Janakiraman, S.; Surendran, A.; Biswal, R.; Ghosh, S.; Anandhan, S.; Adyam, A.
Electrospinning is an efficient technique to produce ultrafine electroactive mat, diameters ranging from few nanometers to micrometers to use as a separator in sodium ion battery. The polyvinylidene fluoride (PVDF) polymer solution was optimized to 19 wt%, applied voltage 25 kV and flow rate of 0.5 ml h-1 to get a bead free ultrafine electroactive structure. The electroactive ?-phase is confirmed by x-ray diffractometer (XRD). Ionic conductivities, electrolyte uptake, wettability, linear sweep voltammetry (LSV) and thermal stability of the electroactive fibrous polymer electrolyte (EFPE) were studied by soaking the separator with a liquid electrolyte of 1 M sodium hexafluorophosphate (NaPF6) dissolved in ethylene carbonate (EC)/propylene carbonate (PC) (1:1 vol%). The EFPE exhibits high ionic conductivity of 1.08 mS cm-1 and electrochemical stability window of 5.0 V versus Na/Na+ under ambient condition. The half-cell containing Na0.66Fe0.5Mn0.5O2 as cathode and EFPE as the separator cum electrolyte showed a stable cycling performance at a current rate of 0.1C. © 2019 IOP Publishing Ltd.