UCLA

The emergence of electrochemical energy storage technologies represents a significant milestone in the pursuit of sustainable energy solutions, offering a viable alternative to fossil fuels. This shift is driven by the urgent need to mitigate environmental impacts and maximize the efficiency of renewable energy systems. Central to this advancement is the development of storage systems with improved energy density (energy stored per unit volume or mass) and power density (rate of energy delivery), crucial for high-capacity applications. Notably, the transition from traditional lithium-ion batteries with organic electrolytes to aqueous battery systems, using water-based electrolytes, brings several advantages. Aqueous batteries are inherently safer, reducing the risk of thermal runaway, vital for large-scale applications like grid storage. They also have a reduced environmental footprint, aligning with sustainability goals, and offer cost-effectiveness due to the use of water-based electrolytes and potential for cheaper materials. Furthermore, aqueous batteries often exhibit superior electrochemical stability and faster ion transport, enhancing cycle life and rapid charging capabilities. Nonetheless, challenges persist, such as the narrow electrochemical stability window of water, which can limit operating voltage and energy density, necessitating innovative electrode and electrolyte design for performance enhancement.The goals of this dissertation have been to investigate some fundamental properties of carbon-based electrodes, specifically carbon nanodots in their chelating chemistry, to tune the electrochemical performance in aqueous energy storage systems. Chapter 2 discusses the role of graphene in enhancing supercapacitors, emphasizing its electrochemical and electrical attributes. Graphene's two-dimensional hexagonal lattice of sp2-hybridized carbon atoms, with exceptional thermal and electrical conductivity, enhances energy storage efficiency. Synthesis methods, including top-down and bottom-up approaches, are reviewed, along with the scalability of graphene production through Graphene Oxide (GO) and reduced Graphene Oxide (rGO). The chapter also explores Carbon Nanodots (CNDs) and Graphene Quantum Dots (GQDs) in energy storage. Chapter 3 focuses on using Carbon Nanodots (CNDs) and derivatives in capacitive energy storage. Strategies to increase their specific surface area and rate capability for high-performance conductive electrodes are discussed, including integrating conductive compounds and polymers. Synthesis methods of CNDs are evaluated, positioning them as components in advanced energy storage systems. Chapter 4 introduces a laser process to enhance sulfonyl compounds' performance in pseudocapacitive charge storage materials. Laser-converted carbon nanodots (CNDs) form conductive scaffolds with high surface areas, enabling efficient Faradaic processes. The resulting electrode exhibits remarkable capacitance and cycling stability, promising for advanced capacitive storage materials. Chapter 5 emphasizes electrode matching for filter electrochemical capacitors (FECs) in green electricity conversion. Effective matching improves capacitance, frequency response, voltage range, and longevity. Analytical methodologies are employed to design a durable filter electrochemical capacitors with exceptional performance metrics. Chapter 6 explores zinc-based batteries for grid-level energy storage. A novel functionalization process using ZnCND and H-ZnCND improves zinc anodes' stability, offering a safer and efficient energy storage solution. Chapter 7 addresses the rechargeability and cycling efficiency of zinc batteries by reengineering the solid-electrolyte interface (SEI) with ZF-rich fluorinated zinc-based SEI, enhancing its mechanical properties and ionic conductivity. This approach leads to dendrite-free zinc metal anodes and promising energy density.