Qualification: 
MSc
Email: 
h_manjunath@blr.amrita. edu
Phone: 
+919845908558

Manjunatha H. currently serves as Assistant Professor (Senior Grade) at the Department of Physics, School of Engineering, Amrita Vishwa Vidyapeetham, Bengaluru Campus. He is currently pursuing his Ph.D. in the area of Solid Polymer Electrolytes in Amrita Vishwa Vidyapeetham. The doctoral thesis is titled "Investigations on Mixed Conducting Solid Polymer Electrolytes.”

Education

  • Ph.D. ( In Progress)
    Amrita Vishwa Vidyapeetham 
  • 2010: M.Phil.
    Prist University
  • 2000: M.Sc.
    Bangalore University

Professional Appointments

Year Affiliation
2009 - Present Assistant Professor (Senior), Amrita School of Engineering, Bengaluru
2005 - 2009 Assistant Professor, Amrita School of Engineering, Bengaluru
2000 - 2005 Lecturer, Oxford College of Engineering, Bengaluru

Major Research Interests

  • Battery Materials: Solid Polymer Electrolytes, Electrode Materials

Courses Taught

  • Engineering Physics
  • Engineering Physics Lab
  • Concepts of Nano Science and Nano Technology
  • Electrical Engineering Materials
  • Nuclear Energy: Principles and Applications
  • Thin Film Physics
  • Physics of Semiconductor Devices
  • Engineering Physics –A
  • Engineering Physics Lab-B
  • Biology for Engineers

Publications

Publication Type: Journal Article

Year of Publication Title

2019

H. Manjunatha, Damle, R., and Kumaraswamy, G. N., “Effect of Mixed Ions and Ion Irradiation on Ionic Conductivity of Solid Polymer Electrolytes”, IOP Conference Series: Materials Science and Engineering, vol. 577, p. 012195, 2019.[Abstract]


It is a well known fact that conductivity in case of solid polymer electrolytes (SPEs) is due to hopping of ions assisted by the segmental motion of polymer chains. It is observed that the ionic conductivity in SPEs increases with increase in the concentration of ions. After certain critical concentration the conductivity starts decreasing due to the formation of ion pairs. In this work, an attempt is made to identify the concentration at which ion pair formation occurs and hence improve conductivity by incorporating two different ions (salts) in the polymer matrix. SPEs with mixed conducting species PEOxLiBryNaBr with different concentration of salts have been prepared and investigated. Also an attempt is made to modify the crystalline phase of the host polymer by low energy ion beam (Oxygen ion, O+1 with energy 100 keV) irradiation. These observations place ion irradiation as an effective tool in improving ionic conductivity in SPEs. Using X-ray diffraction spectra and the temperature dependent conductivity studies of SPEs, the effect of mixed ions and ion irradiation on the ionic conductivity of SPEs is investigated and presented.

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2018

H. Manjunatha, Damle, R., and Kumaraswamy, G. N., “Effect of blending and nanoparticles on the ionic conductivity of solid polymer electrolyte systems”, AIP Conference Proceedings, vol. 1953, p. 030272, 2018.[Abstract]


In the present work, a polymer electrolyte blend containing polymers Poly ethylene oxide (PEO) and Poly (vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) was prepared. The polymer blend was complexed with potassium trifluoromethanesulfonate (KCF3SO3), and titanium oxide nanoparticles (TiO2) (10nm size) were dispersed in to the complex at different weight percentages. The conductivity due to ions in the blend is determined by Ac impedance measurements in the frequency range of 10Hz-1MHz. The nano composite polymer blend containing 5wt% of TiO2 shows a conductivity of 7.95×10−5Scm-1, which is almost 1.5 orders more than polymer electrolyte with PEO as a polymer. XRD studies show a decrease in the coherence length of XRD peaks on addition of nanoparticles, which is due to increase the amorphous phase in the systems. Temperature dependence conductivity studies of the systems shows that, activation energy decreases with increase in the percentage of nanoparticles in the blend.

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2018

H. Manjunatha, Damle, R., Pravin, K., and Kumaraswamy G. N., “Modification in the transport and morphological properties of solid polymer electrolyte system by low-energy ion irradiation”, vol. 24, no. 10, pp. 3027 - 3037, 2018.[Abstract]


The poly(ethylene oxide) (PEO)-based solid polymer electrolyte (SPE) systems consisting of NaBr as a dopant salt are prepared. The stable PEO:NaBr system with 3 wt% of NaBr was subjected to low-energy ion beam irradiation to bring in morphological modification. The irradiated samples are studied using complex impedance spectra to evaluate electrical conductivity and relaxation process in the system. The studies show an increase in conductivity by one order magnitude in the irradiated systems. The dielectric loss tangent (tanδ) curves show a single peak due to strong coupling of ion transport with segmental motion. The resultant relaxation time τ exhibits a continuous decrease indicating increase in segmental dynamics as a result of increased amorphous content in the system. The temperature-dependent studies also indicate that the irradiated systems are more disordered/amorphous compared to pure systems. This fact is further supported by XRD, by observing an increase in peak width associated with reduction in peak intensity. The Raman spectra also support the change in morphology of the system by the appearance of disordered-longitudinal acoustic mode band.

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Publication Type: Conference Paper

Year of Publication Title

2016

H. Manjunatha, Damle, Rb, and Kumaraswamy G. N., “Ion beam irradiation as a tool to improve the ionic conductivity in solid polymer electrolyte systems”, in AIP Conference Proceedings, 2016, vol. 1728.[Abstract]


Solid polymer electrolytes (SPEs) have potential applications in solid state electronic and energy devices. The optimum conductivity of SPEs required for such applications is about 10-1-10-3 Scm-1, which is hard to achieve in these systems. It is observed that ionic conductivity of SPEs continuously increase with increasing concentration of inorganic salt in the host polymer. However, there is a critical concentration of the salt beyond which the conductivity of SPEs decreases due to the formation of ion pairs. In the present study, solid polymer thin films based on poly (ethylene oxide) (PEO) complexed with NaBr salt with different concentrations have been prepared and the concentration at which ion pair formation occurs in PEOxNaBr is identified. The microstructure of the SPE with highest ionic conductivity is modified by irradiating it with low energy O+1 ion (100 keV) of different fluencies. It is observed that the ionic conductivity of irradiated SPEs increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains due to radiation induced micro structural modification.

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2014

H. Manjunatha, Kumaraswamy G. N., Damle, R., and , “Effect of low energy oxygen ion beam irradiation on ionic conductivity of solid polymer electrolyte”, in AIP Conference Proceedings, 2014.[Abstract]


Over the past three decades, solid polymer electrolytes (SPEs) have drawn significant attention of researchers due to their prospective commercial applications in high energy-density batteries, electrochemical sensors and super-capacitors.The optimum conductivity required for such applications is about 10-2 - 10-4 S/cm, which is hard to achieve in these systems.It is known that the increase in the concentration of salt in the host polymer results in a continuous increase in the ionic conductivity. However, there is a critical concentration of the salt beyond which the conductivity decreases due to formation of ion pairs with no net charge. In the present study, an attempt is made to identify the concentration at which ion pair formation occurs in PEO: RbBr. We have attempted to modify microstructure of the host polymer matrix by low energy ion (Oxygen ion, O+1 with energy 100 keV) irradiation. Ionic conductivity measurements in these systems were carried out using Impedance Spectroscopy before and after irradiation to different fluencies of the oxygen ion. It is observed that the conductivity increases by one order in magnitude. The increase in ionic conductivity may be attributed to the enhanced segmental motion of the polymer chains. The study reveals the importance of ion irradiation as an effective tool to enhance conductivity in SPEs.

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