Energy Materials and Devices
As nanomaterials have become easier to synthesize and their basic structures and properties are better understood, their integration into devices with real-life utility has emerged as the next technological frontier. Breakthroughs in energy-related technologies, in particular, are expected from new advances in nanotechnology. Real progress at the convergence of energy and nanotechnology require solutions to many practical challenges related to the scalability and integrability and some of these are addressed in the laboratory.
Electrochemical Energy Technologies
The research is focussed on designing of electrode architecture for high performance of devices. Electrode constitutes an important component of all energy related devices - directly influences the cost and efficiency of devices. The group has expertise in developing electrodes for the electrochemcial devices shown below:
Electrocatalysis for Water Oxidation, Hydrogen Production from Water and Fuel Cells
The fabrication of electrocatalysts has gained importance for the development of efficient energy technologies such as water splitting and fuel cells. In this context, Co3O4 nanoparticles conformally coated on a light weight, 3D and highly conducting carbon cloth is fabricated as a electrocatalyst using an easily synthesized cobalt hexadecylthiolate complex. This method is especially useful for large-scale production as the complex can be synthesized in large quantities and coated on 3D substrates by simple dip-coating method. The optimum loading of the catalyst is achieved through a layer-by-layer assembly of cobalt hexadecylthiolate complex via repeated dip-coating of carbon cloth electrode in the solution. The Co3O4/CC electrocatalyst with optimized loading exhibits remarkable stability over 24 hours with an overpotential of 300 mV at 10 mA/cm2 and Tafel slope of 63.5 mV/dec. The high catalytic activity towards oxygen evolution reaction (OER) in 1 M KOH due to the layer-by-layer dip coating is better than normal Co3O4 and comparable to IrO2 and RuO2 electrocatalyst with a future possibility of commercial-scale production at lower cost.
(Contributors to this work: Ajay Urgunde, Hamid P. K. and Vipin Kamboj)
Energy Storage Devices: Supercapacitors
Fluorination of Graphitic Carbon for Enhanced Supercapacitor Performance
Activated carbon is the ultimate source of carbon electrodes for practical application in energy storage devices as it is commercially available at a much lower cost in contrast to other forms of nanostructured carbon. Recently, fluorinated activated carbon with improved electrical conductivity and wettability have been found to possess better and efficient electrochemical storage properties. However, the development of simple fluorination process is still a challenge. Herein, Selectfluor (F-TEDA) is explored as a fluorinating agent for activated Vulcan Carbon. Fluorination of carbon material resulted in the formation of semi-ionic C-F (F=8.02 at%) and ionic C-F (F=2.71 at%) bonds as observed in XPS analysis along with an increase in defect density (ID/IG) by 33.4%. Symmetric two-electrode supercapacitor cells are assembled in Swagelok-type geometry and specific capacitance for fluorinated carbon is found to increase by ~10 times in contrast to pristine carbon due to induced surface polarization despite a decrease in specific surface area by ~34%, which is remarkable. The fabricated device is stable with negligible capacitance loss over 5,000 cycles resulting in enhanced supercapacitive performance.
(Contributors to this work: Gaurav Bahuguna and Savi Choudhary)