Polymer design for rechargeable batteries with high-energy-density

Abstract

Rechargeable batteries are integral to advancing modern energy storage systems, evolving significantly to meet the demands of contemporary technological applications. This evolution is driven by breakthroughs in materials science and electrochemical engineering, particularly with the introduction of lithium-ion batteries (LIBs) in the early 1990s. These batteries leverage the high electrochemical potential of lithium, offering superior energy density, efficiency, and longevity without the memory effect of previous technologies. The exceptional performance of LIBs is due to their 4 key components: anode, cathode, electrolyte, and separator. Innovations in anode materials, especially, aim to increase lithium-ion storage capacity and improve conductivity and stability. These efforts are crucial as the demand for electric vehicles and large-scale storage systems requires batteries that are not only powerful but also lightweight and compact. The shift towards high-capacity anode materials like silicon (Si) and lithium metal anodes (LMAs) addresses these needs. However, they face challenges such as significant volume changes during operation, causing mechanical instability, active materials loss, and unstable solid-electrolyte-interphase (SEI) formation, leading to capacity fading and safety concerns. This thesis focuses on overcoming these obstacles using polymeric materials, which are pivotal in the manufacturing of batteries for their processability, multifunctionality, and cost- effectiveness. Polymers not only provide structural support and safety but also play crucial roles in maintaining electrode integrity and facilitating ion diffusion. Innovations include designing polymeric binders, separators, and three-dimensional (3D) hosts that enhance the performance and safety of high-energy-density batteries. Novel polymeric binders developed for Si anodes accommodate drastic volume changes and promote stable SEI formation, significantly improving cycle performance. Additionally, for LMAs, which pose risks of dendritic growth and high reactivity, research has focused on developing polymeric separators and 3D host structures which that facilitate uniform lithium-ion flux and enable densely packed lithium metal. This thesis contributes to the development of next-generation batteries by enhancing the energy density and safety of lithium-ion batteries through advanced polymeric materials and anode technologies. Addressing the key challenges associated with high-capacity anodes, this research supports the broader adoption of energy storage solutions that are more efficient, durable, and aligned with sustainable practices.