Faculty Publications
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Item Electroactive poly(vinylidene fluoride) fluoride separator for sodium ion battery with high coulombic efficiency(Elsevier B.V., 2016) Janakiraman, S.; Surendran, A.; Ghosh, S.; Anandhan, S.; Adyam, A.Electroactive separators are recent interest in self-charging rechargeable batteries. In this study, electrospun polyvinylidene fluoride (PVDF) is characterized as an electroactive separator for Na-ion batteries. The intrinsic ?-phase with high porosity of the separator is confirmed from X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM) and Atomic Force Microscopy (AFM) studies. The electroactive separator is immersed in 1M NaClO4-ethylene carbonate (EC)/diethyl carbonate (DEC) (1:1 by weight) solution. The physicochemical characteristics of electroactive separator electrolyte (EaSE) were investigated using sodium ion conductivity, ion transference number and contact angle measurements. Linear and cyclic voltammetry studies were also carried out for the electrolyte system to evaluate oxidation stability window. The inherent ?-phases of the separator as obtained by electrospinning has an ionic conductivity of ~ 7.38 × 10- 4 S cm- 1 under ambient condition. Sodium ion cell made from EaSE with Na0·66Fe0.5Mn0·5O2 as cathode and Na metal as anode has displayed a stable cycle performance with a coulombic efficiency of 92% after 90 cycles. © 2016 Published by Elsevier B.V.Item 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.Item Synthesis and evaluation of a new gel polymer electrolyte for high-performance Li-ion batteries from electrospun nanocomposite of PVDF/Ca–Al-layered double hydroxide(Springer Nature, 2022) Shamitha, C.; Janakiraman, S.; Ghosh, S.; Adyam, V.; Prabhu, K.N.; Anandhan, S.Poly(vinylidene fluoride) (PVDF)/Ca–Al-layered double hydroxide(CAL) (PCL) nanocomposite-based nanofabrics were electrospun for application in lithium-ion batteries as gel polymer electrolyte (GPE). The nanofabric exhibited a high β-phase content of 82.79% after the addition of CAL that was synthesized by co-precipitation method. The PCL-based GPE exhibited enhanced electrochemical properties, such as high ionic conductivity, optimal Li-ion transference number, and improved electrolyte uptake due to the presence of a highly interconnected porous structure. The PCL GPE exhibited an ionic conductivity of 3.54 × 10–3 S cm−1 at ambient temperature, which is much higher than that of pristine PVDF and commercial Celgard® 2400 separators. Moreover, Li/PCL/LiCoO2 cell showed an initial discharge capacity of 140.31 mAh g−1, which is superior to that of PVDF and Celgard® 2400 separators. It also exhibited high coulombic efficiency retention of 99% after 30 cycles of charging. PCL-based GPE showed superior mechanical and low thermal shrinkage properties, indicating its suitability in battery separator application. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to The Materials Research Society.