Transition metal oxides (TMOs) occupy an increasing share in the search for new electrode materials for Li-Ion batteries. Despite promising electrochemical performances (up to 1000 mAh g⁻¹ in the case of conversion), these materials have poor cyclability linked primarily to hysteresis phenomena. To improve their electrochemical performance, one strategy consists of reducing the particle size. A second strategy relies on the incorporation of fluorine directly into electrode materials to limit the solid–electrolyte interface (SEI). Our study focuses on the impact of fluorination on the electrochemical performance of manganese oxide obtained by solid combustion synthesis (SCS). Two fluorinating agents were used: pure gaseous molecular fluorine F₂ and radical fluorine F^• through xenon difluoride XeF₂ decomposition. The use of F₂ results in strong fluorination localized primarily at the particle surface while XeF₂ diffuses deeper into the particle, resulting in the removal of residual carbon from the synthesis by combustion. The electrochemical performance of the oxide fluorinated with XeF₂ reaches more than 750 mAh g⁻¹ after 160 cycles, whereas that of the oxide fluorinated by F₂ barely exceeds that of the non-fluorinated oxide, less than 200 mAh g⁻¹ after 200 cycles.

Nitryl fluoride (FNO₂) and nitrosyl fluoride (FNO) are two nitrogen oxyfluorides that are rarely described in the literature. Their respective syntheses, by combination of nitrogen oxide (NO₂ or NO) and molecular fluorine (F₂), are known to be particularly energetic, which can lead to a flame even at low temperatures. This reactivity, however, has not prevented their use to synthesize exotic inorganic compounds. The simultaneous presence of nitrogen oxides, fluorine, and the nitrogen oxyfluorides formed, all gaseous and very reactive, strongly limits the number of analytical techniques available to precisely monitor the reaction. This article proposes to revisit the synthesis of these two compounds, by very precise monitoring of the pressure inside the reactor coupled with infrared spectroscopy, in a setup specifically built and dedicated to their study.

Heteroatom doping of graphene effectively modifies surface charge, defect density, and electronic structure, with multi-heteroatom co-doping enhancing bond polarization, charge redistribution, and electrochemical performance for advanced energy storage, conversion, and other technological applications. In this work, we report a one-step synthesis of di- and tri-doped graphene via the simultaneous incorporation of fluorine and boron into pristine as well as S- and N-doped graphene, starting from commercially available N- or S-doped graphene. Mild gas–solid fluorination was performed using elemental fluorine diluted in an inert nitrogen atmosphere at controlled temperatures. The presence of a boron-containing precursor enables the in situ generation of BF3, which acts as an effective boron-doping agent during the fluorination process. This approach allows, for the first time, the controlled synthesis of F/B/S-, and F/B/N- -tri-doped graphene materials through a single-step reaction. The doping mechanisms and structural evolution were elucidated using complementary characterization techniques, including Fourier-transform infrared (FTIR) spectroscopy, solid-state nuclear magnetic resonance (NMR) spectroscopy (19F, 11B and 13C), thermogravimetric analysis (TGA) coupled with mass spectrometry (MS) and infrared spectroscopy (IR), and X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and (scanning)transmission electron microscopy ((S)TEM). The results demonstrate that hexagonal boron nitride and molecular fluorine act as precursors for the in situ generation of BF3, which, together with F2, enables efficient and homogeneous incorporation of fluorine and boron into heteroatom-doped graphene carbon frameworks.