Nonaqueous Electrolyte Design for Energy Storage and Electrosynthesis

Author: Ware, Skyler Danielle

Year: 2024

Degree: Dissertation (Ph.D.)

Advisor: See, Kimberly

Committee Members: Lewis, Nathan Saul; Cushing, Scott K.; Reisman, Sarah E.; See, Kimberly

Option: Chemistry

DOI: 10.7907/kx7f-2065

Abstract

Electrochemically driven metal redox has enabled advances in both academic and industrial processes, including production of metals from their ores, storage of renewable energy in batteries and fuel cells, and greener chemical synthesis conditions. While many electrochemical reactions are performed in aqueous solutions, applications in energy storage and organic synthesis often require extreme applied potentials that lie outside the electrochemical stability window of water or necessitate water-free conditions to prevent undesirable side reactions. Herein, we develop tailored non-aqueous electrolytes for applications in both energy storage and organic electrosynthesis and analyze the effects of electrolyte composition on interfacial and electrochemical reactions. First, a series of highly concentrated solvate electrolytes is developed for Li-S batteries, and interfacial reactivity between the solvate electrolytes and the Li anode is investigated in detail. The addition of a fluoroether cosolvent limits electrolyte decomposition at the Li surface, improving cycling stability and enabling new high-temperature applications. Next, samarium(III)/(II) redox is investigated in a variety of non-aqueous electrolytes to support an electrocatalytic cycle for samarium-mediated carbon-carbon bond formation. The coordination environment of the samarium salt, which can be tuned through anion exchange between the electrolyte and the samarium precursor, strongly affects the reversibility and reducing power of the samarium redox couple. Third, electrolyte additives are studied to increase the desolvation barrier of Zn²⁺. When Zn sacrificial anodes are used in organic electrosynthesis, such additives may prevent deleterious cross-plating of Zn²⁺ at the cathode. Finally, a detailed guide to troubleshooting metal sacrificial anodes is presented with special attention to issues commonly encountered in reductive electrosynthesis.

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