Dr. Thirugnasambandam G. Manivasagam currently serves as Assistant Professor at Center of Excellence in Advanced Materials and Green Technologies.

 

 

 

AFFILIATIONS

QUALIFICATIONS

YEAR DEGREE/PROGRAM INSTITUTION
2014 Ph. D. Department of Chemical Engineering and Chemistry,
Eindhoven University of Technology The Netherlands
2007 ​M. Tech. (Materials Science) National Institute of Technology, Tiruchirappalli
2004 M. Sc. (Materials Science) PSG College of Technology, Coimbatore.
2002 B. Sc. (Physics) Sri Ramakrishna Mission Vidyalaya, BharathiarUniversity 

CERTIFICATES, AWARDS, HONORS, AND SOCIETIES

  • National merit scholarship 2002-2004
  • ​DST Inspire faculty award 2014
     

RESEARCH

RESEARCH THEMES

  • Energy Materials
  • Functional Materials
     

RESEARCH INTERESTS

My group’s primary research interest is in the development of materials for energy storage and conversion. We are interested in understanding the fundamental nature of the selected materials for applications such as hydrogen production & storage, and lithium-ion batteries.

Hydrogen Storage:

Hydrogen can be stored by various physical and chemical methods. Worldwide, many materials classes have been investigated concerning their potential to store hydrogen. However, each material class exhibits specific advantages along with disadvantages. Despite the search for a suitable high storage capacity materials that adapts to the standards set by the US-DOE for on-board mobile applications, there seems to be no significant breakthrough in that direction. It has been known that an ideal storage material should have (i) high gravimetric and volumetric capacity, (ii) cost-effective, (iii) no capacity degradation over thousands of cycles, (iv) made from materials that are earthabundant and eco-friendly, (vi) fast kinetics for charge and discharge requiring temperatures no more than 100 °C and ambient pressures. Presently, the only materials which are capable of storing and releasing hydrogen at ambient conditions are LaNi5, TiFe, and therefore they are under large-scale production. However, the gravimetric capacity of these compounds is low, i.e. these materials can store upto 1.2 wt.% and 1.5 wt.% of hydrogen, respectively. A promising class of materials with storage capacities of more than 6 wt.% is Mg-based alloys. Pure MgH2 can store 7.6 wt.% of hydrogen. However the rate of (de)hydrogenation is poor and compound is thermodynamically too stable. The equilibrium pressure is 1 bar at 300˚C. Mg-based systems can be modified to improve the sorption properties, such as temperature and reaction rate. It has been recognized that magnesium can be modified in different ways, e.g., by forming nano particles, alloying Mg with transition metals and adding catalysts. We are synthesizing and characterizing bulk Mg-TM alloys for hydrogen storage nickel and metal hydride battery applications. 

Hydrogen Production:

Photo electrochemical (PEC) water splitting is considered as one of the ultimate solutions to make the hydrogen cycle sustainable as it requires only sunlight and water to generate hydrogen. The thermodynamic voltage for water splitting under standard conditions is 1.23 V and the photoactive materials must generate a photovoltage sufficiently high enough to drive water splitting reactions. Hematite is one of the most favorable materials for PEC water oxidation but they suffer from poor electronic conductivity, low absorption coefficient, short hole diffusion length and high electron-hole recombination rate. Altering the properties (both structural and dopant composition) of hematite nanostructures and forming heterojunctions by use of N-doped graphene and secondary metal oxides with a matching band gap would be a promising route to significantly improving the water splitting capability of α-Fe2O3. We are focusing a) developing highly active and durable graphene and hematite-based photo catalysts, b) determining the effects of synthesis routes on the PEC properties of catalysts, and c) developing a cost effective and environmental friendly photo electrode fabrication route for commercialization.

Lithium-ion batteries:

Graphene has elicited significant interest as anode material for Li-Ion energy storage applications due to its superior conductivity, high theoretical surface area (~ 2630 m2g-1), good mechanical properties, high flexibility, and ease of functionalization. Pre Lithiated-Graphite has been typically used as the anode material for Li-Ion batteries but it has poor kinetics for (de)insertion of lithium during charging and discharging and also a problem of volume expansivity during the same process. Also while the theoretical capacity of graphite is 372 mA.h g-1, the practical capacity is only ~320 mA.h g-1, hence, alternate anode materials are studied to improve the cycling capacity and storage capabilities. Metal oxides such as iron oxide, ruthenium oxide, nickel oxide, tin oxide, and manganese oxide have been studied as potential anode materials. Particularly, iron oxide seems to be more promising for practical applications because of its low cost, high theoretical specific capacity (1007 mAh.g-1), environmentally benign nature and easy handling. But one of the major issues of using iron oxide and in fact, most of the metal oxides, is volume expansivity and low electrical conductivity during high charge-discharge rates and hence, reduced cycle life. It has been shown that graphene/metal oxide nanocomposites exhibit improved electrochemical performance as result of reduced diffusion pathways for Li. Also, it is advantageous to consider nano-sized iron oxide because it can be easily prepared by electrochemical deposition at room temperature without any templates and catalysts. The need for a multilayered graphene-iron oxide structure is mainly due to its enhanced electrical conductivity, cycling durability and lithium storage performance. Also, using multi layered graphene could better accommodate the stresses induced due to the volumetric change during Li alloying/ de-alloying process because of its flexible structure. We aim at developing electrodeposited iron oxide-graphene nanostructures, including multilayer structures.

Electrochromism:

Conceptually, ‘electrochromism’ is the reversible optical change of specific compounds in response to a change in the oxidation state of the involved electro-active species. Metalhydrides expanded the classes of electrochromic materials and were listed among advanced optically switching inorganic compounds. Unlike most of the electrochromic color changing materials, metal hydrides even showed all three optical states (reflecting, absorbing and transmitting states) during the reversible (de)hydrogenation processes without any color change. metal-hydride switchable mirrors can be classified into three generations: rare earth (RE) metal hydrides, magnesium – rare earth (MgRE) metal hydrides and magnesium–transition metal (MgTM) hydrides. Various optical states have been identified during the (de)hydrogenation Mg-based alloys, which seem to be interesting for switchable mirror applications. According to Lambert-Beer’s law, the logarithm of the optical transmission is expected to be a good measure of the hydrogen concentration in a film. We aim at developing Mg based alloys thin films for switchable mirror applications.

KEYWORDS

  • Hydrogen storage
  • Hydrogen Production
  • Metal hydrides
  • Metal-oxides
  • Electrochemistry
  • Photoelectrochemical water splitting
  • ​Electrochromic materials
     

COLLABORATORS

  • Dr. M.V.V. Reddy, National University of Singapore, Singapore.
  • Prof. B.V.R. Chowdari, Department of Physics, National University of Singapore, Singapore.
  • Dr. Kaushik Jayasayee, SINTEF Materials and Chemistry, SINTEF, Norway.
  • Dr. Murali Rangarajan, Center of Excellance in Advanced Materials and Green Technolgies, Amrita Vishwa Vidyapeetham University, Coimbatore.
     

Publications

Publication Type: Journal Article
Year of Publication Publication Type Title
2015 Journal Article T. G. Manivasagam and .H.L.Notten, P., “The Electrochemistry of Hydrogen Storage Materials”, Journal of Materials Chemistry, 2015.
2015 Journal Article T. G. Manivasagam, Ksu, M., Kiraz, K., and Notten, P. H. L., “Influence of Ni and Si on the electrochemical hydrogen storage properties of Mg-Ti binary alloy (in preparation)”, 2015.
2014 Journal Article T. G. Manivasagam, Magusin, P. C. M. M., Iliksu, M., and Notten, P. H. L., “Influence of Nickel and Silicon Addition on the Deuterium Siting and Mobility in fcc Mg-Ti Hydride Studied with 2H MAS NMR”, The Journal of Physical Chemistry C, vol. 118, pp. 10606-10615, 2014.[Abstract]

Fluorite-structured Mg-Ti hydrides are interesting for hydrogen storage applications because of their high gravimetric hydrogen storage capacity, and improved (de)hydrogenation kinetics compared to MgH2. In the present study we have investigated the potential catalytic effect of Ni and Si as third element on the siting and mobility of electrochemically loaded deuterium in ball-milled Mg0.63Ti0.27Ni0.10 and Mg0.63Ti0.27Si0.10 alloys. Magic angle spinning (MAS) 2H NMR reveals that Ni and Si induce new types of deuterium sites in addition to the Mg-rich and Ti-rich sites already present in Mg0.65Ti0.35D1.2. 2D exchange NMR spectroscopy shows a substantial deuterium exchange between the various types of sites, which reflects their close interconnectivity in the crystal structure. Furthermore, the time scale and temperature dependence of the deuterium mobility have been quantified by 1D exchange NMR. The obtained effective residence times for deuterium atoms in the Mg-rich and Ti-rich nanodomains in Mg0.65Ti0.35D1.2, Mg0.63Ti0.27Ni0.10D1.3, and Mg0.63Ti0.27Si0.10D1.1 at 300 K are 0.4, 0.3, and 0.8 s, respectively, and the respective apparent activation energies 17, 21, and 27 kJ mol1. The addition of Ni promotes deuterium mobility inside Mg-Ti hydrides, which is in agreement with the observed catalytic effect of Ni on the electrochemical (de)hydrogenation of these materials.

More »»
2014 Journal Article T. G. Manivasagam, Magusin, P. C. M. M., Srinivasan, S., Krishnan, G., Kooi, B. J., and Notten, P. H. L., “Electrochemical deuteration of metastable MgTi alloys: an effective way to inhibit phase segregation”, Advanced Energy Materials, vol. 4, no. 1, 2014.[Abstract]

Electrochemical deuteration of metastable Mg-Ti alloys is studied. To investigate the dynamics of deuterium atoms in the crystal host, the as-prepared hydrides are examined by means of NMR spectroscopy. Remarkably the host compound, which phase segregates upon gas phase deuteration at high temperatures, preserves its original structure during low temperature electrochemical deuteration. Deuterium atoms exchange dynamically between Mg-rich and Ti-rich sites.

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2012 Journal Article T. G. Manivasagam, Kiraz, K., and Notten, P. H. L., “Electrochemical and Optical Properties of Magnesium-Alloy Hydrides Reviewed”, Crystals, vol. 2, pp. 1410–1433, 2012.[Abstract]

As potential hydrogen storage media, magnesium based hydrides have been systematically studied in order to improve reversibility, storage capacity, kinetics and thermodynamics. The present article deals with the electrochemical and optical properties of Mg alloy hydrides. Electrochemical hydrogenation, compared to conventional gas phase hydrogen loading, provides precise control with only moderate reaction conditions. Interestingly, the alloy composition determines the crystallographic nature of the metal-hydride: a structural change is induced from rutile to fluorite at 80 at.% of Mg in Mg-TM alloy, with ensuing improved hydrogen mobility and storage capacity. So far, 6 wt.% (equivalent to 1600 mAh/g) of reversibly stored hydrogen in MgyTM(1-y)Hx (TM: Sc, Ti) has been reported. Thin film forms of these metal-hydrides reveal interesting electrochromic properties as a function of hydrogen content. Optical switching occurs during (de)hydrogenation between the reflective metal and the transparent metal hydride states. The chronological sequence of the optical improvements in optically active metal hydrides starts with the rare earth systems (YHx), followed by Mg rare earth alloy hydrides (MgyGd(1-y)Hx) and concludes with Mg transition metal hydrides (MgyTM(1-y)Hx). In-situ optical characterization of gradient thin films during (de)hydrogenation, denoted as hydrogenography, enables the monitoring of alloy composition gradients simultaneously. More »»
2012 Journal Article K. Jayasayee, Van Veen, J. A. Rob, Manivasagam, T. G., Celebi, S., Hensen, E. J. M., and de Bruijn, F. A., “Oxygen reduction reaction (ORR) activity and durability of carbon supported PtM (Co, Ni, Cu) alloys: Influence of particle size and non-noble metals”, Applied Catalysis B: Environmental, vol. 111-112, pp. 515 - 526, 2012.[Abstract]

Carbon supported platinum and platinum alloys (PtCo, PtNi and PtCu) for \{PEMFC\} cathodes were prepared and studied for their oxygen reduction reaction activity and durability under potential cycling at 80°C in 0.5M HClO4. Catalysts with different metal alloy composition and particle size were synthesized by annealing at different temperatures to discriminate between the effects of alloying and particle size on the electrocatalytic activity and durability. XRD was used for the structural characterization of pristine catalysts, while the bulk compositions were analyzed by EDS before and after durability tests. XPS was employed to determine the surface composition of selected alloys after durability tests. The particle size of the fresh and aged catalysts was determined by TEM. Rapid dealloying, particularly from non-noble metal rich alloys, was already witnessed for the alloys potentially cycled at room temperature. Significant particle growth depending on the initial particle size was observed for both Pt and Pt alloys after the durability tests. For the alloys with similar initial particle size, the initial electrocatalytic activity depends on the initial alloy composition. Although a 3-fold enhancement in the ORR activity was observed for the non-noble metal rich alloys after initial dealloying, the specific activity of Pt and Pt alloys becomes quite similar at the end of the durability tests. Annealing of Pt/C and Pt alloys at 950°C results in catalysts with the highest specific and mass activity and with the highest stability.

More »»
2011 Journal Article T. G. Manivasagam, Manivasagam, T. G., KUMARAN, S., and T. RAO, S. R. I. N. I. V. A. S. A., “Microstructural refinement and mechanical properties of direct extruded ŻM21 magnesium alloys”, Transactions of Nonferrous Metals Society of China, vol. 21, no. 10, pp. 2154 - 2159, 2011.[Abstract]

Cast ŻM21 magnesium alloys were subjected to symmetric extrusion at four different temperatures (200, 250, 300 and 350 °C) with three extrusion ratios of 4:1, 9:1 and 16:1, respectively. The effects of extrusion parameters such as temperature and extrusion ratio were studied by optical microscopy, X-ray diffraction (XRD) and tensile test. The optical micrographs exhibited various stages of recrystallization, i.e., partial to full recrystallization influencing mechanical properties to good extent. Higher extrusion temperature resulted in coarse grains, whereas finer grains were obtained at higher extrusion ratios. Ultimate tensile strength of this alloy was increased from 160 MPa to 316 MPa after extrusion at 250 °C with an extrusion ratio of 9:1. More »»
Publication Type: Conference Paper
Year of Publication Publication Type Title
2013 Conference Paper T. G. Manivasagam, C.M.M.Magusin, P., and .H.L.Notten, P., “Meta-Stable Mg-Based Hydrogen Storage Alloys : A 2H NMR Study”, in ACTS symposium, Lunteren, The Netherlands, 2013.
2012 Conference Paper T. G. Manivasagam, C.M.M.Magusin, P., Krishnan, G., and .H.L.Notten, P., “Sitting and Dynamics of Electrochemically Deuterated Mg0.65Ti0.35D1.12:A2HNMR Study”, in MRS-ICYRAM2012, Singapore, 2012.
2012 Conference Paper K. .Kiraz, Manivasagam, T. G., Dam, B., and .H.L.Notten, P., “Hydrogen Storage and Optical Switching Abilities of Magnesium Alloy Hydrides”, in MRS-ICYRAM2012, Singapore, 2012.
2011 Conference Paper T. G. Manivasagam, .H.L.Notten, P., and .Kiraz, K., “Multi-component Mg based Hydrogen storage materials”, in ICMAT2011, Singapore, 2011.
2011 Conference Paper T. G. Manivasagam and .H.L.Notten, P., “Multicomponent Mg based Hydrogen storage materials”, in Advances in Dutch Hydrogen and Fuel Cell Research, Eindhoven, The Netherlands , 2011.
2011 Conference Paper T. G. Manivasagam and .H.L.Notten, P., “Multicomponent Mg based Hydrogen Storage materials (paper)”, in (NWO) – ACTS symposium, Lunteren, The Netherlands, 2011.
2009 Conference Paper T. G. Manivasagam, .Kiraz, K., and .H.L.Notten, P., “Multi component Mg based Hydrogen storage materials”, in ACTS symposium, Lunteren, The Netherlands, 2009.

COURSES

  • Material Thermodynamics
  • Advanced Electrochemistry
  • Energy Storage Technologies
     

Summary

My research interest revolves around developing novel materials, structures and morphologies for energy production, storage and conversion. We have synthesized Mg based binary metal hydrides that can store hydrogen upto 5 wt. % and also a potential candidate for electrochromic application.We are currently involved in synthesizing Mg-based ternary alloy hydrides that can be applied in hydrogen storage, electrochromic and Nickel-Metal hydride battery applications. We are alsoin the process of designing multilayermetal oxide thin films for photoelectrochemical water splitting and anode materials for lithium-ion batteries.

Faculty Details

Qualification:

Designation: 
Faculty Email: 
gm_thiru@cb.amrita.edu