Alain Tressaud

Abstract:

Inorganic fluoride materials constitute an important part of solid-state chemistry since they are present today as components in many advanced technologies, for instance in energy storage devices, such as Li-ion batteries, F- ion-based all-solid-state batteries, or fuel cells. Beside this type of applications, fluoride materials are also decisive components in microphotonics, fluorescent chemical sensors, solid-state lasers, nonlinear optics, bio- and medicinal technologies, etc [1]. Most of these outstanding properties can be correlated to the exceptional electronic properties of the element "Fluorine" [2].
The strategic importance of inorganic fluoride materials will be illustrated by some examples:
- In energy storage and conversion fields, fluorinated carbon nano-particles (F-CNPs) have been tested as active materials in electrodes of primary lithium batteries, whereas in secondary Li batteries, 3d-transition metal fluorides and oxyfluorides are proposed as active electrodes.
- Among the huge variety of solid-state d-transition metals, fluorides derived from the perovskite, layered BaCuF₄ and iron fluorides (TTB- K₃Fe₅F₁₅), are noticeable multiferroics, in which magnetism and ferroelectricity coexist.
- Functionalization processes and surface modifications using various fluorination treatments yield nano-sized materials with very high surface areas. In the case of fluorinated nano-carbons, the physical properties that can be drastically modified may concern: electrical conductivity, varying from insulating to metallic behavior, switchable hydrophobic/hydrophilic surfaces of substrates treated with fluorinated rf plasmas, high mobility in FET systems involving fluoro-graphene, and new kinds of fluorinated nano-carbons providing higher potential and energy density values, and thus improving the electrochemical performances of primary Li-battery.
Concerning environmental and sustainable issues, new alternatives are proposed to substitute CFCs, HFCs and PFCs by molecules much favorable for our troposphere because of their lower GWP. In many fields such as the ceramics industry or aluminum production, new technologies allow to considerably lower the level of fluorine and fluoride emission or wastes. Finally, in areas of the world where the level of fluorine in water is dangerously high, various de-fluoridation processes improve the quality of drinking water, lower the risks of fluorosis, and bringing most promising development for these populations [3].

[1] "Progress in Fluorine Science", A. Tressaud Series Editor, Elsevier, USA Vol. 1 - "Photonic & Electronic Properties of Fluoride Materials", A.Tressaud & K. Poeppelmeier Eds. (2016) ; Vol. 2 - "New Forms of Fluorinated Carbons", O. Boltalina & T. Nakajima, Eds. (2016); Vol. 3 " "Modern Synthesis Processes and Reactivity of Fluorinated Compounds", H. Groult, F. Leroux & A. Tressaud, Eds. (2017); Vol. 4 - "Fluorine & Health: Pharmaceuticals, Medicinal Diagnostics, and Agrochemicals", G. Haufe, & F. Leroux Eds. (2018).
[2] Fluorine Chemistry, a thematic issue, Chemical Reviews, V. Gouverneur, K. Seppelt, Eds., Chem. Rev. 115 (2015) 563-1306.
[3] "Fluorine and the Environment", Vol.1: F-emissions and atmospheric chemistry. Vol.2: Green Chemistry, Water, Agriculture, and Analytical aspects, Advances in Fluorine Science Series, A. Tressaud, Ed. Elsevier (2006)