Browsing by Author "Agnihotri, Shruti"

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    Development of novel cathode materials based on MWCNT for energy storage/conversion devices
    (Springer Science and Business Media, LLC, 2017) Agnihotri, Shruti; Rattan, Sangeeta; Sharma, A. L.
    In Chap. 1, already available technology for energy storage solutions like capacitors, lead acid batteries, compressed air energy storage, flywheels has been discussed in order to compare their energy and power densities. Emphasis has been laid on Rechargeable Lithium ion Battery (Li-ion). Various materials which are already explored and used as cathode of battery has also been discussed with their merits and demerits. Further introduction of prepared orthosilicate material with used conductive additive Multiwalled carbon nano tube (MWCNT) has also given. In Chap. 2, methodology used to prepare respective Li2MnFeSiO4 material and its composite with MWCNT has been discussed in detail. Further, in order to validate its electrochemical application, different steps of cell assembly of Lithium half cell fabrication has also been discussed. Chapter 3 comprises of results obtained using standard Field emission scanning electron microscope (FESEM). Effect of used MWCNT on its morphology has been discussed in this chapter. A.C Impedance spectroscopy has been used to study variation in conductivity with respect to bared material. Possible reasons for increased conductivity with morphology has also been discussed in discussion. Chapter 4 includes conclusions drawn from mentioned results. This chapter summarizes measured conductivity values with different concentrations of MWCNT. Improved conductivity with respect to bared orthosilicate material has been pointed in this chapter. ? Springer International Publishing Switzerland 2017.
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    Effect Of MWCNT On Prepared Cathode Material (Li 2 Mn (x) Fe (1-x) SiO 4 ) For Energy Storage Applications
    (AIP Publishing, 2016) Agnihotri, Shruti; Rattan, Sangeeta; Sharma, A. L.
    The electrode material Li 2 MnFeSiO 4 was successfully synthesized by standard sol–gel method and further modified with multiwalled carbon nano tube (MWCNT) to achieve better electrochemical properties. Our strategy helps us to improve the performance and storage capacity as compared with the bared material. This novel composite structure constructs an efficient cation (Li + ) and electron channel which significantly enhance the Li + ion diffusion coefficient and reduced charge transfer resistance. Hence leads to high conductivity and specific capacity. Characterization technique like Field emission scanning electron microscopy (FESEM) has been used to confirm its morphology, structure and particle size which comes out to be of the order of ~ 20 to 30 nm. Lesser particle size reveals better electrochemical properties. Electrical conductivity (~10 -5 Scm -1 ) of MWCNT doped oxide cathode materials was recorded using ac impedance spectroscopy technique which reflects tenfold increment when compared with pure oxide cathode materials. Cyclic voltametery analysis has been done to calculate specific capacity and potential window of materials with and without CNTs. The results obtained from different techniques are well correlated and suitable for energy storage applications.
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    Optimization of concentration of MWCNT in terms of performance of prepared novel cathode material for energy storage
    (Integrated Science, 2017) Agnihotri, Shruti; Sharma, A. L.
    The successful synthesis of a novel cathode material Li2MnFeSiO4 (LMFS) was done using thestandardSol-Gel technique. To improve the electrical conductivity of cathode material different concentration (wt/wt) of MWCNT are incorporated into LMFS generating composite Li2MnFeSiO4/MWCNT via solution method. In order to achieve better electron passage to particle–particle boundaries, MWCNT is considered as one of the ideals and appropriate conductive additive. The Li2MnFeSiO4 nanoparticles are dispersed homogeneously in CNT's network and assembled as micro-sized porous spherical particles. Such special composite structure constructs an efficient Li+ and electron channel, which significantly enhance the Li-ion diffusion coefficient and reduced the charge transfer resistance, hence may lead to high electrical conductivity. Carbon nano tube not only deposited on the surface, but also provide theinterconnected network. This continuous conductive network enhances the electronic conductivity of the insertion/de-insertion cycles. Complex impedance spectroscopy (EIS) is used to estimate the electrical conductivity of prepared samples. The Li2MnFeSiO4/MWCNT with 12 wt% of CNT delivers highest electrical conductivity (i.e. ~10-3 Scm-1) which is at par with desire for the energy storage applications.