Current Projects

Li Anode Protection

Li metal has high theoretical capacity (~3800 mAh/g). It has been considered as an ideal anode material since the inception of rechargeable batteries decades ago. However, it is not yet used in commercial batteries due to safety hazard. The root of the issue is related to the fact that Li is susceptible to dendrite formation that can grow with cycling and ultimately lead to short circuit. Another major issue is related to the low oxidation potential of Li. The electrolytes reacts irreversibly with Li anode resulting in the loss of active material. This has detrimental effect on batteries shelf life.
In collaboration with experimentalists at the Sandia National Laboratories we are investigating possible physical blocking materials that has promising properties of suppressing dendrite formation and simultaneously minimizing direct electrolyte/Li contact. Simulations ranging from few hundred atoms, using Density Functional Theory (DFT), to million atoms, applying classical molecular dynamics (MD) as implemented in LAMMPS, are being used to model this system.

Li-S Batteries

Li-S battery is one of the most promising beyond Li-ion battery chemistries that is being actively pursued by the scientific community. It uses inexpensive and non-toxic Sulfur (S). Coupled with low cost and high theoretical gravimetric and volumetric energy density, this system is presently considered as a promising candidate to power the electric vehicles. A video on left (taken from Youtube and created by Fraunhofer IWS) shows schematics of a Li-S battery charge/discharge processes.
One of the major challenge in Li-S battery is related to the formation of polysulfides (PS) during discharge that can dissolve in electrolyte and traverse across to cathode resulting in catastrophic capacity limiting reactions. There has been numerous attempts to limit the PS dissolution with advanced cathode nanostructures and application of sparingly solvating electrolytes that restricts PS shuttling.

With the confinement of PS, the electrochemistry is bound to occur at the surface of these batteries. Hence it is critical that we understand the transport properties of the redox end-members (REMs), namely S and Li2S. We are currently working on studying the coherent and incoherent transport phenomena using theoretical constructs ranging from hybrid functional DFT to Green's function techniques.

MOF

Metal organic frameworks (MOFs) are porous materials ideally suited for applications such as hydrogen storage, carbon capture and catalysis.
Many of the MOFs exhibit limited resistance to moisture. We are currently studying MOF-5, a widely recognized high storage density MOF, for stability against humidity. Advanced MD techniques such as Thermodynamic Integration scheme is being used to model finite temperature reaction mechanisms.

Contact me to learn more about my research.