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Author: search.filters.author.Khalifa, M.

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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.
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    Graphene-based elastomer nanocomposites: A fascinating material for flexible sensors in health monitoring
    (CRC Press, 2022) Khalifa, M.; SelvaKumar, S.; Anandhan, S.
    [No abstract available]
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    Polymer Electrolytes and Separators for Magnesium-Ion Batteries
    (CRC Press, 2024) Singh, R.; Khalifa, M.; Janakiraman, S.; Adyam, V.; Anandhan, S.; Biswas, K.
    Magnesium (Mg)-ion-based rechargeable batteries are attractive because magnesium is bivalent, abundant, non-toxic, and inexpensive. In the development of Mg-ion batteries (MIBs) with high energy densities, their ionic conductivity and safety have become important features. The most commonly used cathodes are Mo6S8, MoO3, V2O5, MnO2, and TiO2, but they are limited due to low voltages (<2.0 V) and low specific capacities. Therefore, electrolytes are needed to improve the voltage stability and ease of synthesis. In this chapter, polymer electrolytes and separators in MIBs with liquid or gel electrolytes are briefly outlined. Polymer electrolytes are classified into two categories, namely solid polymer electrolytes and gel polymer electrolytes (GPEs). Solid polymer electrolytes have several advantages such as high safety, lightweight, and favorable mechanical properties, but their weakness is their relatively lower ionic conductivity. To overcome these issues, GPE, which is a combination of liquid electrolyte and a polymer matrix, is explored. Poly(vinylidene fluoride)-based gel electrolytes showed a high ionic conductivity of the order of 10−3 S cm−1 at room temperature. In GPEs, an electrolyte is used as an ion transport medium between the electrodes, whereas a polymer membrane acts as a separator, thereby eliminating the physical contact between the electrodes. © 2025 selection and editorial matter, Prasanth Raghavan, Akhila Das, and Jabeen Fatima M. J.
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    Rubber-based lightweight nanocomposites: spectroscopic characterization
    (Elsevier, 2025) Khalifa, M.; Anandhan, S.
    Carbon nanofiller-based rubber nanocomposites have gained considerable attention in academia and industries because of their suitability in various applications, including automobiles, sports, aerospace, medical, and structural components. The addition of carbon nanofillers, such as carbon nanotubes, graphene, carbon fibers, carbon black, and graphite, helps in tuning the electrical conductivity, thermal conductivity, barrier properties, and mechanical properties of rubbers. Some of these characteristics and properties of rubber nanocomposites can be studied using spectroscopic techniques. These techniques are rapid, nondestructive, highly sensitive, and provide molecular-level information. Various spectroscopic techniques, such as Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), etc., have been adopted that provide information on the dispersion of fillers, interfacial interactions, molecular bonds, orientations, elemental compositions, impurities, etc. This chapter provides an overview of the use of FTIR, Raman, XPS, and NMR spectroscopies in the characterization and analysis of carbon nanofiller-rubber composites. © 2026 Elsevier Inc. All rights reserved..