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End date: 2020

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    ELECTROCHEMICAL EVOLUTION OF FEPO4 SPHERICAL NANO PARTICLES AS EFFICIENT NEGATIVE ELECTRODE MATERIAL FOR HYBRID SUPERCAPACITORS
    (Bhabha Atomic Research Centre (BARC), Mumbai, 2020-01-21) Priyadharsini N
    A newer of FePO4 electrode material have synthesized through facile combustion method for the fabrication of aqueous type hybrid supercapacitors. The phase purity, homogeneity and the functional groups present in the synthesized FePO4 are characterized through X-ray diffraction and FTIR measurements. Field emission scanning electron microscopy (FESEM) images show that there is a uniform and spherical shaped nano particles present in the electrode material. The electrochemical properties of the FePO4 electrode are studied in various alkaline aqueous electrolytes to explore their superior electrochemical performances. Among these aqueous electrolytes, the FePO4 electrode provides a maximum specific capacitance of 400 F g-1 in 1 M NaOH at 2 mV s-1 and also retained about 93% of the initial capacitance value even after 5000 cycles at a current density of 1 mA cm-2. These results suggest that the synthesized sample has higher potential as a newer electrode material for hybrid supercapacitors. By employing FePO4 as a negative electrode in hybrid supercapacitor configuration of FePO4║Co3O4, it exploits an outstanding electrochemical with an enhanced energy density of 18 W h kg−1 at an improved power density of 443 W kg−1 and protracted cyclic stability for about 5000 cycles.
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    TUNING DIELECTRIC PROPERTIES OF STRONTIUM BASED TITANATE (SRTIO3) AND MANGANATE (SRMNO3) PEROVSKITES FOR MICROWAVE ANTENNA APPLICATIONS
    (Nirmalagiri College, Kerala, 2019-06-12) D, Sathiyapriya; N, Priyadharsini
    Interesting properties of perovskite materials such as very stable in structure, Ferroelecticity and high dielectric constant are attracted to study for electronic device applications. In this work, we have considered Strontium Manganate (SrMnO3) and Strontium Titanate (SrTiO3) structures to tune the perovskite in the Micro Strip Patch Antenna Application. Various Synthetic Techniques were used to prepare the material. In the current work, we synthesized SrMnO3 and SrTiO3 using combustion method by taking Sr(NO3)3, (C4H6MnO4.4H2O) and citric acid (for SrMnO3), and Sr(NO3)3 , TiO2 and citric acid ( for SrTiO3) as the starting precursors. The formation of the prepared material was confirmed through X-ray diffraction (XRD). From the XRD analysis, it is found that SrMnO3 has the Hexagonal Crystal Structure and the SrTiO3 has the Cubic Crystal Structure. In addition, we have calculated the crystallinity, crystallite size, lattice constants and cell volume to confirm the structural information of the considered material. Surface morphology of the sample clearly depicts the uniform formation of clusters of nano particles. FTIR analysis shows the presence of the metal oxygen (M – O) bonds. The Perovskite are highly Efficient and Adundance. The Cost of the Raw materials and Fabrication was low. The Perovskite band gap can be tuned by the chemical subsititution for the high energy performances in future.
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    ELECTROCHEMICAL ANALYSIS OF FEPO4 SPHERICAL NANO PARTICLES AS EFFICIENT NEGATIVE ELECTRODE MATERIAL FOR HYBRID SUPERCAPACITORS
    (Bhabha Atomic Research Centre (BARC), Mumbai, 2018-09-26) Priyadharsini N
    A battery type electrode material of FePO4 nano particles have synthesized through facile combustion method for the fabrication of aqueous type hybrid supercapacitors. The phase purity, homogeneity and the functional groups present in the synthesized FePO4 are characterized through X-ray diffraction and FTIR measurements. Field emission scanning electron microscopy (FESEM) images show that there is a uniform and spherical shaped nano particles present in the electrode material. The electrochemical properties of the FePO4 electrode are studied in various aqueous electrolytes of 1 M LiOH, 1 M KOH and 1 M NaOH to explore their superior electrochemical performances. Among these aqueous electrolytes, the FePO4 electrode provides a maximum specific capacitance of 400 F g-1 in 1 M NaOH at 2 mV s-1 and also retained about 93% of the initial capacitance value even after 5000 cycles at a current density of 1 mA cm-2. These results suggest that the synthesized sample has higher potential as a newer electrode material for hybrid supercapacitors. By employing FePO4 as a negative electrode in hybrid supercapacitor configuration of FePO4║Co3O4, it exploits an outstanding electrochemical with an enhanced energy density of 18 W h kg−1 at an improved power density of 443 W kg−1 and protracted cyclic stability for about 5000 cycles. The higher electrical conductivity of FePO4║Co3O4 hybrid device is confirmed by the lower charge transfer resistance (5.5 Ω) of EIS measurements, which is slightly increased to 38 Ω after 5000 cycle’s performance. From these results, it is evident that the FePO4║Co3O4 hybrid supercapacitor shows better electrical conductivity, higher diffusion of ions and more charge propagation behaviour.
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    SYNTHESIS AND CHARACTERIZATION OF FEPO4 SPHERICAL NANO PARTICLES AS EFFICIENT ELECTRODE MATERIAL FOR HYBRID SUPERCAPACITOR
    (PSGR Krishnammal College for Women, Coimbatore, 2018-01-03) S, Seema; B, Agnes latha; N, Priyadharsini
    A battery type electrode material of FePO4 nano particles have synthesized through various synthetic routes of combustion, hydrothermal and ultrasonication methods for the design of aqueous supercapacitors. The phase purity, homogeneity and the functional groups present in the synthesized FePO4 are characterized through X-ray diffraction and FTIR measurements. Field emission scanning electron microscopy (FESEM) images show that there is a uniform and spherical shaped nano particles present in the compound synthesized from combustion technique than the remaining samples. The electrochemical properties of the FePO4 electrode are studied in various aqueous electrolytes of 1 M LiOH, 1 M KOH and 1 M NaOH to explore their superior electrochemical performances. Among these alkaline electrolytes, the FePO4 electrode provides a maximum specific capacitance of 400 F g-1 in 1 M NaOH at 2 mV s-1 and also retained about 93% of the initial capacitance value even after 5000 cycles at a current density of 1 mA cm-2. These results suggest that the fabricated electrode material has high potential as a newer electrode material for hybrid supercapacitor.
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    EXPLORATION OF KNIPO4 AS A NEW CLASS OF POSITIVE ELECTRODE MATERIAL FOR HYBRID SUPERCAPACITORS
    (Bannari Amman Institute of Technology, Sathyamangalam, 2017-08-17) N, Priyadharsini; R, Kalai Selvan
    A facile sol-gel thermolysis route was adopted to synthesize KNiPO4 nano-sheets for the hybrid supercapacitor applications. The phase purity, homogeneity, and functional groups present in the synthesized KNiPO4 were characterized through X-ray diffraction and FTIR measurements. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images showed that the nano-sheet-like particles were loosely stacked. The electrochemical properties of the KNiPO4 electrode were studied in various aqueous-based electrolytes such as 1 M LiOH, 1 M NaOH, and 1 M KOH to explore their superior performances. Among these electrolytes, the KNiPO4 electrode provided a maximum specific capacity of 278 C g-1 in 1 M KOH at 5 mV s-1. A hybrid supercapacitor was fabricated using the synthesized KNiPO4 as the positive electrode and activated carbon as the negative electrode in a 1 M KOH aqueous electrolyte. The supercapacitor exhibited a specific capacitance of 48 F g-1 in 1 M KOH at 0.6 mA cm-2 and energy density of 13 Wh kg-1 at a power density of 59 W kg-1. In addition, the hybrid system retained 93% of its initial specific capacitance even after 2000 cycles. KNiPO4 based hybrid system thus exhibits super characteristics and hence is a promising candidate for high-performance electrochemical energy storage devices.
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    PHOTOCATALYTIC DEGRADATION OF POLYSTYRENE - AG NANOCOMPOSITE
    (Anna University, Chennai, 2017-01-06) D, Anitha Jennifer; N, Priyadharsini
    Abstract: The polymer nanocomposite has become world-wide research interest for developing polymeric materials with improved and desired properties by incorporation of the nanoscale materials into polymer matrix [1, 2]. Due to their nanometre size dispersion, nanocomposites exhibit markedly improved properties when compared with the pure polymers or conventional composites. In this work, the solid-phase photocatalytic degradation of polystyrene-silver nanocomposite (PS/Ag) was investigated under the ambient air in order to assess the feasibility of developing photodegradable polymers. PS-Ag nanocomposites were prepared by using Ex-situ solution method in which various concentration (0.5%, 1%, 1.5%) of Ag nanoparticles were dispersed by constant stirring. The prepared nanocomposites such as PS-Ag (0.5%), PS-Ag (1%), PS-Ag (1.5%) and pure PS were exposed to UV irradiation for various time intervals i.e. 0, 30 and 60h. On increasing irradiation time, increase in degradation efficiency was observed. Moreover, the effect of UV radiation on its structural, optical and degradation properties of various PS-Ag nanocomposites have been studied. Further, SEM analysis reveals the morphological nature of the nanocomposites and confirms the photo degradation of nanocomposites. Results indicate that an increase in AgNPs concentration with polystyrene matrix enhances the photo-catalytic degradation of PS-Ag nanocomposite. Hence the influence of Nano silver particles and its efficient contribution in degradation of polymer was confirmed. The process of photo degradation has been enhanced because of the addition of silver nano particles in the polymer matrix and the results are clearly elucidates the effect of silver in the degradation of polystyrene host materials.
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    SOL-GEL THERMOLYSIS SYNTHESIS OF LIMNPO4 FOR SUPERCAPACITOR ELECTRODES
    (CECRI, Karaikudi, 2016-12-08) N, Priyadharsini; R, Kalai Selvan
    As a novel approach, LiMnPO4 has tried as a positive electrode material for the super capacitor system because of its large operating voltage, low cost and environmental friendliness. It is a promising cathode material for Li ion batteries due to its higher redox voltage, 4.1 V vs. Li/Li+, compared to other cathode materials [1-5]. In the present work, LiMnPO4 was synthesized via sol-gel thermolysis using lithium dihydrogen phosphate, manganese acetate were starting materials with citric acid as a fuel. Physical properties, structural and elemental analysis of electrode materials were studied by TEM, X-ray diffraction and EDAX measurements. Surface morphology of the sample shows a thin layer of carbon coating in the as-prepared sample which enhances the electronic conductivity in the charge carrier discharge. The electrochemical performance of the LiMnPO4 electrode materials were studied using cyclic voltammetry, galvanostatic charge-discharge cycling and electrochemical impedance spectroscopy in a three electrode system at a potential range from -0.6 to 0.4 V vs Hg/HgO in 1 M LiOH electrolyte solution. The result exhibits a specific capacitance of 151 F/g at a scan rate of 5 mV s-1. The maximum specific capacitances of 123 F/g for total electrode at 1 A/g were achieved in 1M LiOH solution. These encouraging results promote interest in developing such electrode materials for super capacitor applications, including nontoxic and greener components compared with current organic based devices.
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    PERFORMANCE EVOLUTION OF AG-TIO2 NANO COMPOSITE BASED FIBER OPTIC SURFACE PLASMON RESONANCE SENSOR
    (Post Graduate and Research Department of Chemistry and Physics held at PSGR Krishnammal College for Women, Coimbatore, 2015-12-07) M, Tharani; N, Priyadharsini
    In this work, the solid-phase photocatalytic degradation of polystyrene (PS) and polystyrene-silver (Ag) nanocomposite were investigated under the ambient air in order to assess the feasibility of developing photodegradable polymers. PS-Ag nanocomposites were prepared by using PS solution in which various weight percentage (10, 20) of Ag nanoparticles were dispersed by constant stirring. The prepared nanocomposites such as PS, PS-10%Ag and PS-20%Ag were exposed to UV irradiation for various time intervals i.e. 30, 60, 90 and 120 h. On increasing irradiation time, increase in degradation efficiency was observed. Moreover, the effect of UV radiation on its structural, optical and degradation properties of various PS-Ag nanocomposite has been studied. Further, SEM analysis reveals the morphological nature of the nanocomposites and confirms the degradation of nanocomposites. Results shows that an increase in Ag concentration with Polystyrene enhances the photo-catalytic degradation of PS-Ag nanocomposite. Hence the influence of Nano silver particles and its efficient contribution in degradation of polymer was confirmed.
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    PHOTOCATALYTIC DEGRADATION OF POLYSTYRENE AND POLYSTYRENE-AG NANOCOMPOSITE
    (Coimbatore Institute of Technology (CIT), Coimbatore, 2015-12-02) D, Anitha Jennifer; S, Sindhu; N, Priyadharsini
    In this work, the solid-phase photocatalytic degradation of polystyrene (PS) and polystyrene-silver (Ag) nanocomposite were investigated under the ambient air in order to assess the feasibility of developing photodegradable polymers. PS-Ag nanocomposites were prepared by using PS solution in which various weight percentage (10, 20) of Ag nanoparticles were dispersed by constant stirring. The prepared nanocomposites such as PS, PS-10%Ag and PS-20%Ag were exposed to UV irradiation for various time intervals i.e. 30, 60, 90 and 120 h. On increasing irradiation time, increase in degradation efficiency was observed. Moreover, the effect of UV radiation on its structural, optical and degradation properties of various PS-Ag nanocomposite has been studied. Further, SEM analysis reveals the morphological nature of the nanocomposites and confirms the degradation of nanocomposites. Results shows that an increase in Ag concentration with Polystyrene enhances the photo-catalytic degradation of PS-Ag nanocomposite. Hence the influence of Nano silver particles and its efficient contribution in degradation of polymer was confirmed.
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    HYDROTHERMAL SYNTHESIS OF MN DOPED TIO2 NANO PARTICLES FOR DILUTE MAGNETIC SEMICONDUCTORS
    (Vellore Institute of Technology, Vellore, 2014-03-10) N, Priyadharsini; A, Nancy
    The TiO2 nano particles are synthesized of Manganese doping through a novel hydrothermal method. The undoped and doped nanostructures were systematically investigated employing X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), and Fourier transform infrared (FTIR) analysis. The space group of the material and associated lattice parameters was ascertained through XRD analysis. The Energy Dispersive Spectroscopy analysis gives the proportion of the chemical composition of the sample synthesized with and without Mn doping. The magnetic properties of the compound are measured through Vibration sample magnetometer (VSM). It is observed that the ferromagnetic behavior of the compound improved largely due to the replacement of Mn ions with Ti. This enhanced ferromagnetic property of the material will be functional for the dilute magnetic semiconductors (DMS). From these observed results, room temperature ferromagnetism behavior can be explained by polaron formation of charge carriers