BITS Faculty Publications
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Item Electrical transport and structural investigations in Cu2O substituted AgI-Ag2O-V2O5 glass-ceramic nanocomposites(AIP, 2012-06) Dalvi, AnshumanGlass-ceramic nanocomposites in Cu2O substituted AgI-(Ag2O)1-x-(Cu2O)x-V2O5 superionic system are prepared by annealing the melt-quenched glasses above the crystallization temperatures. Structural and electrical properties have been investigated. Scanning electron microscopy suggests the existence of fine particles of size 20-200 nm dispersed in the annealed glass matrix. Samples are essentially ionic and stable under conductivity-temperature cycles upto ∼ 160 °C. It is found that the conductivity in the nanocomposites increases with Cu2O substitution and highest conductivity is found to be ∼ 2 × 10−3 Ω−1cm−1 for x = 0.3 at room temperature. Differential scanning calorimetry scans confirm the existence of silver iodide crystallites in all the glass-ceramic compositions.Item Understanding of ionic transport in Ntp dispersed Na+ ion hybrid polymer nanocomposites using Xanes spectroscopy(International Atomic Energy Agency, 2018) Dalvi, AnshumanPresent investigation focuses on conductivity-structure correlation in NaTi2(PO4)2 (NTP) NASICON embedded novel hybrid polymer composites. Structural and electrical investigations suggest that for low NTP content salt ions prefer to move through polymer for electrical transport. However, for higher content, the surfaces as well as inner states of NTP crystallites facilitate the ionic conduction as suggested earlier alsoItem Li+ NASICON nanocrystallites in ionic glasses: A potential nano composite system for all-solid-state Li+ ion batteries(AIP, 2019-07) Dalvi, AnshumanIn order to prepare a suitable oxide based solid electrolyte for Li+ ion batteries, Li+ NASICON LATP nanocrystallites [LiAl0.3Ti1.7(PO4)3] have been externally dispersed in fast ionic oxide glassy system, viz, 60[Li2SO4]-40[Li2O-P2O5]. To prepare this novel composite, milling assisted synthesis route was adopted in which ionic glass and LATP were separately ball milled, subsequently mixed and pelletized. The present work reports that even for a very small amount of LATP (1 wt%) in the mixture, the conductivity exhibits a significant enhancement. Structural and electrical properties of the composite with a typical composition of 1%(LATP)-99%(60LSLP) have been reported. X-ray diffraction confirmed that milling leads to reduction in the size of both the glass grains and the LATP crystallites. These novel composites have been found to be potential candidates for all solid-state battery applicationsItem Novel Na3Zr2Si2PO12–polymer hybrid composites with high ionic conductivity for solid-state ionic devices(Elsevier, 2020-03) Dalvi, AnshumanIncorporation of PEO based Na+ ion polymer electrolyte in Na3Zr2Si2PO12 (NZSP) NASICON results into novel hybrid composite formation with high ionic conductivity of ~10−4 Ω−1 cm−1 at room temperature. Thus compositions 63NZSP-37(PEO1−xNaIx) for x = 0.03–0.13 have been prepared. The ionic transport mechanism investigated using impedance and X-ray absorption near edge structure spectroscopy suggests decoupling of Na+ ions from the polymer matrix, and significant role of NASICON crystallites in providing pathways for ionic conduction. Compositions with large salt content exhibit reversible conductivity-temperature cycles at least upto 100 °C. The best conducting composite (x = 0.13) exhibits appreciable electrochemical stability window of 4.64 V vs Na/Na+.