Design of composite foil anodes for lithium-ion batteries

Heligman, Brian Theodore
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In this work, multi-phase metallic foils are developed for use as high-capacity lithium-ion battery anodes. The core of the approach relies upon using severe plastic deformation to generate dense nanostructures containing multiple metallic phases with differing electrochemical activity. In the first chapter, a historical context is provided both for the development of lithium-ion battery technology broadly and alloying anode materials specifically. This introduction serves to outline the motivation for the work that follows. In the second chapter, the experimental methods utilized to develop this new class of alloying anode materials are outlined. The third chapter entails a detailed investigation of the zinc-tin binary metal system to understand its operation as a battery anode. In this work, we highlight the unmatched volumetric capacity realized by the foil form factor. The fourth chapter investigates the electrochemical reactions of alloying metals more broadly and develops a generalized framework for understanding the implementation of metallic foil anodes in the modern battery system. This work provides a robust foundation for the design and implementation of foil anodes, highlighting the viable materials systems and contextualizing their performance in a modern cell architecture. The fifth chapter represents an investigation of how the electrochemical cycling of a metallic foil anode alters its microstructure and impacts performance. We investigate the processes associated with electrochemical cycling that transform the bulk metallic foil into a porous electrode in-situ. The sixth chapter introduces a new technique for the manufacturing of foil anodes broadly that greatly expands the nanostructured composite foil anode design space. In this work, we investigate the performance and degradation mechanisms of a model Sn/Cu system, highlighting the elimination of active material loss enabled by the inactive matrix. The final chapter is a summary of the work carried out for this dissertation.