Dr. Dhamodaran Santhanagopalan is an Assistant Professor and DST Ramanujan Fellow at Amrita Center for Nanosciences and Molecular Medicine. Before joining the center, he was a Postdoctoral Fellow at the Laboratory for Energy Storage and Conversion, University of California, San Diego, for three years. Prior to postdoctoral work, he was a faculty at Physics Department, IIT Kanpur, for about three and a half years. Dr. Dhamodharan received PhD from University of Hyderabad, and M.Phil. and M.Sc degrees in Physics from Pondicherry University. During his postdoctoral work he was part of the Energy Frontier Research Centre led by Stony Brook University, funded by US Department of Energy. During this tenure, he was also a Guest researcher at Brookhaven National Laboratory, New York, and Pacific Northwest National Laboratory, Washington. As a part of this work, he established for the first time, fabrication of electrochemically active solid-state nano-batteries using focused ion beams. This significant contribution enabled in situ galvanostatic biasing of nano-batteries in the TEM to investigate interface effects, a bottle-neck in energy storage devices. During his tenure at IIT Kanpur, he developed several ion beam facilities and a GaN growth facility for high quality nanostructures with novel morphologies that are useful for opto-electronic applications. Two of the GaN nanostructure images were published as journal cover pages in Materials Today (2011) and Nano Today (2012). He has over 50 peer reviewed journal publications and 10 proceedings to his credit. He has been invited as a speaker in several national and international conferences. He is also an active reviewer for several international journals on topics related to his research interests. In the recent past, he has worked on micro/nano-fabrication and semiconductor nano-materials. Dr. Dhamodharan is currently focusing on energy storage technologies such as, lithium ion batteries, all-solid-state batteries and supercapacitors. The goal is to significantly improve both energy and power densities without compromising safety and cycling stability.

Publications

Publication Type: Journal Article
Year of Publication Publication Type Title
2016 Journal Article S. Mohapatra, Shantikumar V Nair, Santhanagopalan, D., and Alok Kumar Rai, “Nanoplate and mulberry-like porous shape of CuO as anode materials for secondary lithium ion battery”, Electrochimica Acta, vol. 206, pp. 217-225, 2016.[Abstract]

Facile hydrothermal synthesis of nanoplate and mulberry-like porous shape of CuO nanostructures was developed as anode materials for application in lithium ion batteries. The powder X-ray diffraction patterns of both the samples were indexed well to a pure monoclinic phase of CuO with no impurities. The CuO sample synthesized at different pH and reaction temperature exhibited nanoplate with average width and length of ∼150-300 nm and ∼300-700 nm and mulberry-like porous shape of CuO with average length of ∼300-400 nm. Electrochemical tests show that the lithium storage performances of both the nanoplate and mulberry-like samples are influenced more closely to its structural aspects than their morphology and size factors. The CuO nanoplate electrode exhibits high reversible charge capacity of 279.3 mAh g-1 at 1.0C after 70 cycles, and a capacity of 150.2 mAh g-1 even at high current rate of 4.0C during rate test, whereas the mulberry-like porous shape of CuO anode delivers only 131.4 mAh g-1 at 1.0C after 70 cycles and 121.7 mAh g-1 at 4.0C. It is believed that the nanoplate type architecture is very favorable to accommodate the volume expansion/contraction and aggregation of particles during the cyclic process. In contrast, the mulberry-like porous morphology could not preserve the integrity of the structure and completely disintegrated into nanoparticles during Li+ ion insertion/deinsertion due to the loose contact between the particles. © 2016 Elsevier Ltd. All rights reserved.

More »»
2016 Journal Article P. Preetham, Mohapatra, S., Shantikumar V Nair, Santhanagopalan, D., and Alok Kumar Rai, “Ultrafast pyro-synthesis of NiFe2O4 nanoparticles within a full carbon network as a high-rate and cycle-stable anode material for lithium ion batteries”, RSC Advances, vol. 6, pp. 38064-38070, 2016.[Abstract]

NiFe2O4 nanoparticles fully anchored within a carbon network were prepared via a facile pyro-synthesis method without using any conventional carbon sources. The surface morphology was investigated using field-emission scanning electron microscopy, which confirmed the full anchoring of NiFe2O4 nanoparticles within a carbon network. The primary particle size of NiFe2O4 is in the range of 50-100 nm. The influence of the carbon network on the electrochemical performance of the NiFe2O4/C nanocomposite was investigated. The electrochemical results showed that the NiFe2O4/C anode delivered a reversible capacity of 381.8 mA h g-1 after 100 cycles at a constant current rate of 1.0C, and when the current rate is increased to a high current rate of 5.0C, a reversible capacity of 263.7 mA h g-1 is retained. The obtained charge capacity at high current rates is better than the reported values for NiFe2O4 nanoparticles. The enhanced electrochemical performance can be mainly ascribed to the high electrical conductivity of the electrode, the short diffusion path for Li+ ion transportation in the active material and synergistic effects between the NiFe2O4 nanoparticles and carbon network, which buffers the volume changes and prevents aggregation of NiFe2O4 nanoparticles during cycling. © The Royal Society of Chemistry 2016.

More »»
2016 Journal Article Za Wang, Santhanagopalan, D., Zhang, Wc, Wang, Fc, Xin, H. Lc, He, Kc, Li, Jd, Dudney, Nd, and Meng, Y. Sa, “In situ STEM-EELS observation of nanoscale interfacial phenomena in all-solid-state batteries”, Nano Letters, vol. 16, pp. 3760-3767, 2016.[Abstract]

Behaviors of functional interfaces are crucial factors in the performance and safety of energy storage and conversion devices. Indeed, solid electrode-solid electrolyte interfacial impedance is now considered the main limiting factor in all-solid-state batteries rather than low ionic conductivity of the solid electrolyte. Here, we present a new approach to conducting in situ scanning transmission electron microscopy (STEM) coupled with electron energy loss spectroscopy (EELS) in order to uncover the unique interfacial phenomena related to lithium ion transport and its corresponding charge transfer. Our approach allowed quantitative spectroscopic characterization of a galvanostatically biased electrochemical system under in situ conditions. Using a LiCoO2/LiPON/Si thin film battery, an unexpected structurally disordered interfacial layer between LiCoO2 cathode and LiPON electrolyte was discovered to be inherent to this interface without cycling. During in situ charging, spectroscopic characterization revealed that this interfacial layer evolved to form highly oxidized Co ions species along with lithium oxide and lithium peroxide species. These findings suggest that the mechanism of interfacial impedance at the LiCoO2/LiPON interface is caused by chemical changes rather than space charge effects. Insights gained from this technique will shed light on important challenges of interfaces in all-solid-state energy storage and conversion systems and facilitate improved engineering of devices operated far from equilibrium. More »»
Faculty Details

Qualification:

Designation: 
Faculty Email: 
dsgopalan20710@aims.amrita.edu