Browsing by Author "Banerjee, Sarbajit"

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A Multiscale Approach to Magnesium Intercalation Batteries: Safer, Lighter, and Longer-Lasting: Justin Andrews
Chemistry; TAMU; https://hdl.handle.net/20.500.14641/219; NASA-Washington
1. EXECUTIVE SUMMARY: Research Goal: The goal of this research has been to design and develop the basic building blocks of inherently safer electrochemical energy storage vectors as replacements for conventional Li-ion batteries. A focus was placed on exploring metastable phase space to identify viable vanadium oxide cathode materials that are capable of reversibly inserting multivalent ions and Li ions from aqueous electrolytes. These materials have been developed with an eye towards the design of all-printed batteries. Brief Background and Motivation: Lithium-ion batteries are the gold-standard for electrochemical energy storage due to their unrivaled combination of high voltage and exceptional specific and volumetric energy densities; however, the development of ‘beyond-Li-ion’ battery technologies has received considerable attention in an attempt to mitigate growing safety concerns, rising materials criticality constraints, and energy storage limitations enforced by the monovalency of the Li-ion. Safety issues in Li-ion batteries are derived from the intrinsic reactivity of Li and manifest in catastrophic failure arising from dendrite formation and1,2 thermal runaway,2,3 which are further exacerbated by the high flammability of most Li-ion battery electrolytes2. These safety problems are of great concern, particularly in applications, such as manned space flight, where safety and device endurance are paramount. The development of inherently safer battery technologies that do not compromise on energy storage capacity is thus an urgent imperative. In the case of Mg-ion batteries, it has been argued that the full realization of Mg batteries (i.e., an Mg battery which includes a metallic Mg anode) would enable significant improvements to both safety (e.g., it has been claimed that Mg is not dendrite forming, Mg has a higher melting point than Li thereby reducing the risk of thermal runaway)12 and energy storage density thereby making them safer, lighter and longer-lasting. Indeed, the projected improvements in the volumetric and specific energy densities enabled by this technological pivot would lead to transformational reductions in weight and volume of the packaged cells, relative to existing Li-ion cells, in principle establishing Mg batteries an immediately attractive alternative to Li-ion technology.19 However, the lack of suitable cathode materials capable of reversibly storing the highly polarizing Mg2+ (only a couple of viable oxide materials)17,20–25 has significantly stymied progress towards their full realization. In an effort to address this technological knowledge gap, this research has focused on leveraging the discovery of a successful ?-V2O5 Mg-ion cathode, a major breakthrough during the first year of this NASA NSTR fellowship, towards the development and optimization of additional cathode materials. A closed-loop design approach, has been implemented to elucidate cathode design principles based on experimental evaluation of V2O5 intercalation cathode materials and aided by first-principles calculations and synchrotron characterization techniques.20,26 This approach has led to the discovery of several new V2O5 polymorphs (?’-V2O5, ?-V2O5, ?-V2O5) that have exhibited promising results as cathode materials in Li-ion, multivalent ion, and aqueous Li-ion batteries. Attention has furthermore been given to scaling the synthesis of these materials to enable the design of large-scale prototypes. While this research has focused on the fundamental aspects of the chemistry of these materials it has also sought to achieve functional devices, with a focus on 3D printing of these materials for the design of flexible batteries.
DMREF: Collaborative Research: A Blueprint for Photocatalytic Water Splitting: Mapping Multidimensional Compositional Space to Simultaneously Optimize Thermodynamics and Kinetics
Chemistry; TAMU; https://hdl.handle.net/20.500.14641/219; National Science Foundation
NON-TECHNICAL DESCRIPTION: Sunlight is a vast source of renewable energy but its intermittent nature means that its utilization requires a means of storing this energy. One attractive approach for solar energy storage is to harness the energy of sunlight to split water into hydrogen and oxygen i.e. solar generated fuels. The solar generated fuels can be combusted to release energy efficiently with water as the only by-product. As a result, this approach avoids the deleterious consequences of greenhouse emissions that accompany the combustion of conventional fossil fuels. The complex cascade of reactions required to harvest sunlight and split water into hydrogen and oxygen present a formidable scientific challenge. The project seeks to develop hybrid materials as the catalyst for water splitting, such that individual components are assembled and function synergistically. The project further works towards employing components that are highly tunable in terms of their energy levels, thereby providing a versatile platform that can be optimized for converting sunlight and water into fuel. Employing a judicious mix of calculations from supercomputers and selective experiments accelerates the rationally design of materials for efficient solar energy storage within chemical bonds. The project team mentors young scientists from underrepresented groups and engages K-12 students and teachers in activities that emphasize the opportunities made available by big data and solar energy. TECHNICAL DESCRIPTION: The project explores the design of programmable heterostructured platforms for photocatalytic water splitting based on interfacing ternary vanadium oxide bronzes with semiconductor quantum dots. In the former compounds, metal cations are intercalated within a variety of open vanadium oxide frameworks, enabling a multitude of compositional possibilities and considerable energy level tuning. Moreover, the energy levels of quantum dots can also be tuned as a function of composition as well as size and the presence of cores. Photocatalytic water splitting requires not just the appropriate alignment of energy levels but also precise control of charge transfer dynamics. Interfacing two versatile and tunable components yields a rich multidimensional space for identification of effective photocatalytic architectures for water oxidation that yield holes at potentials only minimally positive to the water oxidation potential, thereby allowing for efficient conversion of sunlight to solar fuels. The multidimensional parameter space is mapped through a closely integrated and iterative combination of first-principles structure prediction, electronic structure calculations, diversified materials synthesis, detailed spectroscopy, high-throughput screening, and big data analytics. The activity involves development of an open-source platform for statistical analysis and mining of spectroscopic data. A summer research activity engages undergraduates from diverse backgrounds.
DMREF: Collaborative Research: A Blueprint for Photocatalytic Water Splitting: Mapping Multidimensional Compositional Space to Simultaneously Optimize Thermodynamics and Kinetics
Chemistry; TAMU; https://hdl.handle.net/20.500.14641/219; National Science Foundation
NON-TECHNICAL DESCRIPTION: Sunlight is a vast source of renewable energy but its intermittent nature means that its utilization requires a means of storing this energy. One attractive approach for solar energy storage is to harness the energy of sunlight to split water into hydrogen and oxygen i.e. solar generated fuels. The solar generated fuels can be combusted to release energy efficiently with water as the only by-product. As a result, this approach avoids the deleterious consequences of greenhouse emissions that accompany the combustion of conventional fossil fuels. The complex cascade of reactions required to harvest sunlight and split water into hydrogen and oxygen present a formidable scientific challenge. The project seeks to develop hybrid materials as the catalyst for water splitting, such that individual components are assembled and function synergistically. The project further works towards employing components that are highly tunable in terms of their energy levels, thereby providing a versatile platform that can be optimized for converting sunlight and water into fuel. Employing a judicious mix of calculations from supercomputers and selective experiments accelerates the rationally design of materials for efficient solar energy storage within chemical bonds. The project team mentors young scientists from underrepresented groups and engages K-12 students and teachers in activities that emphasize the opportunities made available by big data and solar energy. TECHNICAL DESCRIPTION: The project explores the design of programmable heterostructured platforms for photocatalytic water splitting based on interfacing ternary vanadium oxide bronzes with semiconductor quantum dots. In the former compounds, metal cations are intercalated within a variety of open vanadium oxide frameworks, enabling a multitude of compositional possibilities and considerable energy level tuning. Moreover, the energy levels of quantum dots can also be tuned as a function of composition as well as size and the presence of cores. Photocatalytic water splitting requires not just the appropriate alignment of energy levels but also precise control of charge transfer dynamics. Interfacing two versatile and tunable components yields a rich multidimensional space for identification of effective photocatalytic architectures for water oxidation that yield holes at potentials only minimally positive to the water oxidation potential, thereby allowing for efficient conversion of sunlight to solar fuels. The multidimensional parameter space is mapped through a closely integrated and iterative combination of first-principles structure prediction, electronic structure calculations, diversified materials synthesis, detailed spectroscopy, high-throughput screening, and big data analytics. The activity involves development of an open-source platform for statistical analysis and mining of spectroscopic data. A summer research activity engages undergraduates from diverse backgrounds.
I-Corps: Super-slick Coatings for the Handling of Viscous Fluids in Extreme Environments
Chemistry; TAMU; https://hdl.handle.net/20.500.14641/219; National Science Foundation
The broader impact/commercial potential of this I-Corps project derives from the anticipated reduction of energy consumption and cleaning expenditures incurred by any industry dealing with the handling of viscous liquids. The technology that is the focus of this project is a thin-film coating that is repellant to both water and oil and can withstand high temperatures. Such coatings are expected to find broad applicability in oil tankers, railcars, and trucks used to transport viscous fuels. The coatings will bring end-users considerable benefits in terms of reduced cleaning and repair costs while enabling improved energy efficiency and reducing the volume of fluids discarded during transportation. The technology is further of relevance to the design of nozzles for additive manufacturing, the processing of nuclear waste streams, and the robotic handling of specialty chemicals. In all of these applications, the coating will allow for viscous fluids to be delivered without adhesion and contamination of surfaces and with the added benefit of protecting the underlying substrate from corrosion. Benefits to society will include more efficient fuel utilization and reduced exposure of workers to potentially hazardous substances. This I-Corps project is based on research that has led to the development of thermally robust and highly textured coatings that readily glide both water and viscous oil droplets. Nature has an abundance of surfaces that are not wetted by water droplets (e.g., lotus leaves or shark skin); however, surfaces that are not wetted by low-surface-tension liquids, such as oils, do not exist in nature. This project is based on coatings that in laboratory tests are not wetted by either oil or water. The extreme non-wettability of these surfaces derives from the creation of thermally robust three-dimensional texturation spanning multiple length scales within ultra-thin metal or ceramic films, which gives rise to an interconnected network of trapped air pockets. Grafting molecules with intrinsically low wettability onto the surfaces of porous films yields extended surfaces that are non-wettable by water or oil. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.