Christopher D. Klaassen
(Texas Tech. University)
ChemE PhD: “Creating Synergy between Graphene and Redox Mediator for Li-Air Battery Cathodes”
My research deals with studying the cathode structure and electrolytes used in Lithium Air batteries. Carbon based cathodes are prominent within Li-Air battery research due to their rigidity, high surface area, and low cost. Through deposition layering techniques and carbothermal reduction of metal oxides, I plan on increasing the cycle life of Li-Air batteries by reducing poisoning side reactions while maintaining oxygen diffusion pathways in the carbon substrate.
(Institute of Technology, Nirma University)
ChemE PhD: “Graphite/Graphene/Silicon Hybrids for Li-ion Battery Anodes“
The current state of art Lithium ion batteries are unable to satisfy the demands for EV applications due to their low energy density. One of the main reasons for this low energy density is the use of Graphite as the anode material which has a limited theoretical capacity. Silicon has been the most promising alternative due its extraordinary theoretical capacity. However, Silicon anode undergoes enormous volume expansion resulting in severe capacity decay. Thus, mitigation of this volume expansion has been a stumbling block for its commercialization. My research focusses on engineering void spaces for the effective accommodation of silicon volume expansion. I also carry out in-situ volume expansion measurements via dilatometer to quantify the reduction in volume expansion due to the incorporation of these pores. My research goal is to mitigate volume expansion in the more commercial milled silicon microparticles. Experiments and numerical simulations will be both investigated to arrive at a more fundamental understanding of the fracture mechanics involved in the lithiation and delithiation of the silicon anode.
(East China University of Science and Technology)
ChemE PhD: “Mesoscale Modeling for Directed Self-Assembly Process of Block Copolymers“
My research is about using molecular dynamic method in simulating the self-assembly (DSA) of polystyrene-poly (methyl methacrylate) diblock copolymers (BCP) directed via chemoepitaxial method. The formed structure can be applied in the manufacturing of micro electronic devices, thus BCP DSA can be an economic and promising alternative for EUV lithography. Some issues in this process are required to be solved such as defectiveness, critical dimension variation and line space variation, which all are my research goals.
(National Taiwan University)
ChemE PhD: “Synergy of Graphene Nanoribbons and Graphene Sheets for High-Rate Li-S Batteries“
My research is focusing on the utilization of nanomaterials, like graphene nanoribbons (GNRs), in Li-S batteries. In our previous work, Li-ion batteries with the addition of GNRs, produced by unzipping carbon nanotubes (CNTs), exhibited improved electrochemical performances compared with the batteries with CNTs. Inspired by this achievement, my study deals with the replacement of graphene sheets with GNRs in the cathodes of Li-S batteries. The composition of cathodes has been modified through air-controlled electrospray, to construct a crosslinked network. The two-dimensional structure of GNRs helps build up inter-connected networks, which can increase the electroconductivity, confirmed by the electrochemical impedance spectroscopy (EIS), and modify the porosity, indicated through pore size distribution profiles. My research goal is to alleviate the polysulfide shuttle effect and improve the electrochemical performances of Li-S batteries at high C-rates, with the aid of nanomaterials and porous structures. The synthesis of functional GNRs and simulations of Li diffusion could be the next development of my work.
(Georgia Institute of Technology)
ChemE PhD: “High Rate High Loading Li-S Batteries“
My research aims at designing high sulfur-loading cathodes of lithium sulfur battery and improving its rate capability and cyclability. As the state-of-art Li-ion battery reaching its theoretical limit, Li-S battery has been recognized as one of the most promising candidates for next-generation cost-efficient energy storage, benefiting from its high gravimetric capacity (5x of Li-ion) and being the 4th abundant element in earth ‘s crust. My research focuses on the most pressing challenges of high sulfur-loading Li-S batteries, including the polysulfide shuttle effect and the low conductivity of discharge products. I will start from the fundamental understanding of transport phenomena, including nucleation and failure mechanism, adsorption and diffusion of polysulfides, etc. Both experiments and numerical simulations will be investigated as a cross-validation.
(University of Pennsylvania)
ChemE PhD: “Optimization of Tuneable Electrochemical Species and Membrane Architectures for Use in Metal-Free Organic Redox-Flow Batteries“
My work focuses on the synthesis and optimization of new electrochemical species, as well as the development of new cost-effective membrane frameworks, for use in organic quinone-based redox-flow battery (RFB) systems. With the rising demand for energy and the shift toward renewable forms of generation, the issue of reliable, energy-dense forms for storage is becoming increasingly important. RFBs offer a unique response to this demand, yet existing organic-based systems are faced with very low energy densities and high costs per kilowatt-hour. To address these challenges, I will be using organic synthesis techniques to develop a library of quinone-based cathode molecules and to explore new, electrochemically-stable polymeric membranes for incorporation into RFB cells.
(The City College of New York)
ChemE PhD: “Synthesis and Fabrication of Exfoliated Graphene from Synthetic vs Natural Graphite Using a Taylor-Couette Flow Reactor“
My research focuses on the synthesis and fabrication of few layer graphene (FLG) and expandable graphite (EG) using a Taylor-Couette reactor (TCR). My work is based on the dissertation work of previous graduate student, Mohammed AlAmer, who initially developed the TCR in our laboratory and explored the synthesis of FLG, EG and graphene oxide (GO). The graphenic products from the TCR are used in various applications in our laboratory ranging from Li-ion batteries, Heat Dissipation, EMI Shielding and Graphene Fiber. Currently, my work explores the use of FLG and EG in synthesis of graphene fiber via wet spinning to explore thermal switching behavior of electrical conductivity of the graphene fibers. Additionally, under a partnership with Saudi Aramco, I will be exploring the synthesis of graphenic products from synthetic vs natural graphite sources and comparing their behavior in several applications.
Vaidik R. Shah
ChemE PhD: “Integration of Gel-Electrolyte component in Li-S batteries”
ChemE MS: “Effect of Binder on the Volume Expansion of Silicon/Graphene Anodes”
Sanjana Sham Sunder Bharadwaj
ChemE MS: “Motionless 3D printing based on guiding electrically charged jet with programmable electric relay array”
ChemE MS: “Conductive Membrane Coatings and Carbon Electrodes Modification for Metal-free Quinone-Based Redox Flow Batteries”
ChemE MEng: “Design of Silicon/Graphene Hybrid Anodes for High Rate Li-ion Batteries”