(6ba) Hierarchical Hybrid Assembly of Functional Nanomaterials

Functional nanomaterials will play critical role in many future technologies related to energy, environment and health. Next generation hybrid or plug-in-hybrid vehicles would require high-power, high-energy density energy storage devices with lower emission for sustainability. To achieve these goals, it is essential to design, identify and sythesize materials that can accommodate efficient transport of ions and electrons in addition to high surface area. Energy storage devices based on nanoscale materials (nanoparticles, nanotubes or nanofibers of electroactive polymers, metal oxides and carbon nanotubes) recently gained significant interest to afford high-power, high-energy density without compromising cycle life.  During my postdoctoral research at MIT, I’ve developed expertise in the design of novel electrode assembly for energy storage devices. I focused on developing hybrid electrodes based on conjugated polymers (Polyaniline, PANi), metal oxides (TiO₂), graphene oxide (GO) and multi-walled carbon nanotubes (MWNT); these nanostructured hybrid electrodes performed exceptionally well (compared to graphitic electrodes) delivering high-power, high-capacity simultaneously for electrochemical pseudocapacitors that  suitable for electric vehicles or plug-in electric vehicles. Along with conventional electrode development, I designed alternative layer-by-layer assembled electrodes based on electrostatic interaction of nanomaterials. The film architecture, assembly technique and post treatment were optimized to create high performance electrodes. These electrodes were engineered to achieve high electronic conductivity and high porosity for improved ion transport of aqueous or organic electrolytes rendering higher capacitance than graphite electrodes with excellent mechanical and electrochemical stability over thousands of cycles. The development of hybrid electrodes of TiO₂,  MWNTs and PANi nanofibers with controlled aspect ratio and morphology exhibits attractive potential in terms of improved electronic conductivity and porosity that are competitive with the expensive state-of-the-art RuO₂. However, these multilayer electrodes of nanoscale materials would reach a performance limit unless we optimize the selection of electrolytes which affect ion conduction and thereby overall electrochemical performance. Polymer-based gel electrolyte could be a solution to address this challenge that could be part of the separator membrane in the overall electrochemical cell design. In addition, my Ph.D research experiences on polymeric membrane design and fabrication would allow me to develop such novel separator membranes.   In future, as an independent researcher, I am interested in the design and facile synthesis of nanomaterials and their assembly for hierarchical electrodes and electrolytes.  Using thses electrodes, my lab will focus on fundamental aspects of charge storages, ion transport which could be ultimately translated to manufacturing. These nanostructured materials along with polymeric/ionic gel electrolyte would have tremendous potential to impact the overall electrode design and performance for improve energy storage devices like metal-air batteries and hybrid supercapacitors.