Fluorination in advanced battery design

Abstract

The increasing demand for high-performance rechargeable batteries, particularly in energy storage applications such as electric vehicles, has driven the development of advanced battery technologies with improved energy density, safety and cycling stability. Fluorine has emerged as a crucial element in achieving these goals, owing to its hydrophobicity, robust bond strength and stability, exceptional dielectric properties and strong electronegativity and polarization. These attributes provide fluorinated battery components with high thermal and oxidative stability, chemical inertness and non-flammability. Importantly, fluorinated materials also facilitate the formation of a thin, protective film of corrosion products at the metal–electrolyte interface, which serves as a barrier against further chemical reactions with the electrolyte. Fluorinated species are now used in a wide range of battery components, including solid and liquid electrolytes, electrolyte additives, solvents, binders and protective layers for electrodes. This Review explores the design and utilization of fluorine-containing species in advanced batteries, focusing on the relationship between the chemical structure of the species and its impact on battery performance. Additionally, given the regulatory landscape surrounding the use of fluorinated compounds, we discuss the current challenges and future directions related to the responsible reuse and recycling of fluorinated materials in battery-related components. Incorporating fluorine into battery components can improve the energy density, safety and cycling stability of rechargeable batteries. This Review explores the broad use of fluorinated compounds in battery design, examines the relationship between their chemical structure and battery performance and discusses the challenges and opportunities of fluorinated batteries within the present regulatory framework.