published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management

Energy storage is a necessity for the electrification of the modern world and the progression towards renewable energy. Designing new and innovative energy storage alternatives is one of the many challenges taken on by the Nuckolls group at Columbia University. More precisely, organic materials for energy storage with facile synthesis methods, non-toxic materials, and compatibility with aqueous electrolytes are a focus of this research. For this purpose, Perylenediimide (PDI) is the chosen primary molecular building block, that has enabled design of redox active materials due to its versatility as a structural unit, as well as its remarkable electrochemical performance. In this thesis 3 classes of materials based on PDI - small molecules, polymer networks, and COF materials - are compared; providing insights into how their design impacts electrochemical performance. Chapter 1 provides an overview of existing organic materials for energy storage. In particular, explaining the limitations, challenges, current landscape, and future of organic materials for battery and pseudocapacitive applications. This research area confronts current traditional energy storage strategies, such as lithium-ion batteries, with new organic alternatives that offer opportunities that could be more eco-friendly alternatives to lithium-ion batteries in specific applications. Chapter 2 describes the synthesis and characterization of PHATN, the highest performing aqueous n-type pseudocapacitor based on the PDI molecular backbone integrated into a 3-dimensional polymer network, and the relationship between electrochemical performance and structural contortion generated because of the molecular design. This is accomplished by benchmarking against a non-contorted linear polymer and comparing their electrochemical properties. This work provides the foundation for chapters 3 and 4. Chapter 3 expands on the use of molecular contortion as a design principle for molecular electronics, associating molecular contortion to electrochemical performance by generating helical inspired PDI polymers. This design reveals that the helical motif allows for enhanced electronic communication between the redox moieties and leads to higher device performance. Chapter 4 utilizes linear PDI polymers as a non-contorted control in comparison to the helical inspired polymers described in chapter 3. This linear motif reveals the competing design principle of increased surface area for electrolyte access to redox sites which is shown to increase device performance. Chapter 5 discusses a COF inspired redox active 2-dimensional polymers (RA-2DP) based on PDI materials and how the structural motif and conductive linkers can improve electrochemical performance. This chapter validates the design criteria outlined in chapter 4 and explains how these RA-2DPs and similar structures can enhance energy storage in organic materials. Collectively, this work provides a structured story of PDI materials, their potential as energy storage materials, and the design principles that have led to increased performance. The work completed in this thesis points towards structured and porous redox active organic materials as next generation energy storage alternatives. With the consideration of renewable energy and challenges with existing energy storage options, it is our hope that organic materials will contribute to this ever evolving and growing research area to create a more sustainable and environmentally friendly future.