Faculty Publications
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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.Item Understanding the interplay of solution and process parameters on the physico-chemical properties of ZnO nanofibers synthesized by sol-gel electrospinning(Institute of Physics, 2023) Prabhu, N.N.; Rajendra, B.V.; Anandhan, S.; Murthy, K.; Jagadeesh Chandra, R.B.; George, G.; Kumar, B.; Shivamurty, B.Aging populations and the increase in chronic diseases worldwide demand efficient healthcare tools for simple, rapid, and accurate diagnosis and monitoring the human health. In this context, gas sensors are used to analyze the type of gas in the breath to diagnose chronic diseases. Metal oxide and ceramic nanofibers (NFs) produced by the electrospinning (ES) method have been investigated for potential use as gas sensors in the engineering and medical sectors. The material and process parameters are the main influencing factors on the functional performance of electrospun metal oxide NFs. Zinc oxide (ZnO) based NFs are used in various gas sensors due to the wide band gap (3.37eV), large exciton binding energy, and high mobility of charge carriers of ZnO. In this research, we made an attempt to study the effect of poly(vinyl alcohol) (PVA) and zinc acetate dihydrate (ZnAc2) concentrations and feed rate, voltage, spinneret tip-to-collector distance (TCD), and pyrolysis temperature on the physical properties of ZnO NFs. An average fiber diameter of 119 nm was obtained after pyrolysis at 600 °C of electrospun fiber produced from an aqueous PVA solution of concentration 15 w% with 7.5 w% ZnAc2 based on the weight of PVA. The grain size, transmittance, structural defects, and band gap energy of NFs were found to increase as a function of the pyrolysis temperature, which could be beneficial for the functional applications of these NFs. © 2023 The Author(s). Published by IOP Publishing LtdItem Probing the influence of strontium doping and annealing temperature on the structure and biocompatibility of hydroxyapatite nanorods(Royal Society of Chemistry, 2024) Patil, H.G.; Rajendran, A.; Lenka, N.; Kumar, B.S.; Murugesan, S.; Anandhan, S.Among numerous biologically important metal cations, strontium (Sr2+) has received much attention in bone tissue regeneration because of its osteoinductive properties combined with its ability to inhibit osteoclast activity. In this study, strontium-doped hydroxyapatite (Sr-HAp) nanorods with varying molar ratios of Ca : Sr (10 : 0, 9 : 1, 5 : 5, 3 : 7 and 0 : 10) were synthesized using the chemical precipitation technique. The synthesized Sr-HAp nanostructures were characterized using powder X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy, energy dispersive X-ray spectroscopy, and Raman and Fourier transform infrared (FTIR) spectroscopies to understand their structural and morphological features, and composition. XRD results revealed the formation of HAp nanostructures, whose unit cell volume increased as a function of the dopant level. The reaction process investigation showed the formation of hydroxyapatite (HAp), strontium apatite (SAp) and various Sr-HAp phases. FESEM micrographs displayed the morphological transformation of Sr-HAp from nanorods to nanosheets upon increasing the dopant level. In the FTIR spectra, the bands of the PO43− group shifted towards a lower wavenumber upon increasing the dopant concentration in Sr-HAp that signifies the structural distortion due to the presence of a large amount of strontium ions. The peaks of PO43− and OH− vibrations in the Raman spectra were further analysed to corroborate the structural distortion of Sr-HAp. Selected area electron diffraction patterns obtained using TEM reveal the reduced crystallinity of Sr-HAp due to Sr-doping, which is in line with the XRD results. Finally, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay showed that the synthesized Sr-HAp has no toxic effect on the survival and growth of mesenchymal stem cells. In summary, the synthesized novel Sr-HAp nanorods exhibit great promise for bone tissue engineering applications. © 2024 The Royal Society of Chemistry.Item Solvothermally synthesized dopant-free anatase-titania nanostructures for efficient photocatalytic degradation of crystal violet under violet irradiation(Elsevier Ltd, 2025) Mohapatra, A.; Murugesan, S.; Anandhan, S.The anatase polymorph of titania is known for its photocatalytic behavior. In this study, titania nanoparticles synthesized through sol-assisted solvothermal process carried out in an autoclave were utilized as photocatalyst under violet radiation for the degradation of a model pollutant, namely crystal violet. The presence of titania in the anatase form was confirmed by x-ray diffraction. Electron microscopy revealed the coexistence of rod-like and spherical-shaped structures in the nano-titania. The average diameters were 9.8 nm and 12 nm for the spherical nanoparticles and the cylindrical ones, respectively. The band gap energy of titania as calculated from the uv–vis spectroscopy was 3.22 eV, which is in line with its theoretical value. The specific surface area of the nano-titania was 39.179 m2/g, and the total pore volume was 0.05 cc/g, which indicates the presence of large number of active sites on the surface of the photocatalyst for the adsorption of pollutant molecules. Excitation and emission spectra of titania were acquired using photoluminescence spectroscopy to ascertain the presence of surface defects. Subsequently the photocatalytic degradation of crystal violet using the anatase titania nanoparticles under violet light irradiation was studied. Under violet irradiation, the dopant-free anatase titania was able to efficiently photodegrade (at loading of 200 mg/L) 1L crystal violet solution of 20 ppm concentration within 90 minutes. The results indicate that this nano-titania could be used an alternate in the place of the systems reported hitherto in literature, which were either doped with heavy metal-based systems or blended with graphene. The result is a leap forward in sustainable water treatment. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.