Theibault, Monica2024-04-052024-04-052023-08Theibault_cornellgrad_0058F_13844http://dissertations.umi.com/cornellgrad:13844https://hdl.handle.net/1813/114778323 pagesThe development and deployment of multiple forms of electrical energy storage systems will be vital to meeting growing global energy needs while effectively decarbonizing all stages of the energy ecosystem. The production of hydrogen fuels, via water splitting, is of practical relevance for meeting global energy needs and mitigating the environmental consequences of fossil-fuel-based transportation. Water photoelectrolysis has been proposed as a viable approach for generating hydrogen, provided that stable and inexpensive photocatalysts with conversion efficiencies over 10% can be discovered, synthesized at scale, and successfully deployed. Starting with 70,150 compounds in the Materials Project database, the proposed protocol yielded 71 candidate photocatalysts, 11 of which were synthesized as single-phase materials. Follow up work revealed, via computation, a further 13 potential photocatalysts, which were tested for their photocatalytic hydrogen generation, as well as their electrochemical properties (via CV). The deeply collaborative nature of this project allowed for a further two follow up works, providing even more potential photocatalysts to meet future energy needs. In today’s renaissance of high-energy-density secondary batteries, lithium–sulfur (Li–S) batteries represent one of the most promising candidates for the next generation of renewable energy storage systems due to sulfur’s high theoretical specific capacity of 1675 mA h g–1 and high earth abundance. Through rigorous and detailed electrochemical studies of lithium polysulfides via rotating disk electrode (RDE) voltammetry, we have investigated the kinetics of the redox reactions and explored candidate catalysts to potentially overcome/mitigate the polysulfide shuttle effect. From these RDE studies, supported by comprehensive electronic structure calculations of conversion-type surface reactions, we had an initial “proof of concept” hit for a rigorous method of catalyst testing using commercial WSe2. From this proof of concept, I expanded the project to the novel and catalytically exciting class of materials, high entropy sulfides, providing evidence both of catalysis of the lithium polysulfide redox reaction and evidence of the “cocktail effect” theorized for high entropy sulfide materials. With both of these highly collaborative projects, I have aided in the analysis of new materials for energy storage applications, helping usher us into a green energy future.enAttribution-NonCommercial-ShareAlike 4.0 InternationalBatteriesCatalystsElectrical Energy StorageElectrochemistryHydrogen FuelLithium Sulfurdissertation or thesishttps://doi.org/10.7298/sasz-ve67