Ionothermal synthesis of polyanionic electrode material Na3V2(PO4)2FO2 through a topotactic reaction

Jacob Olchowka (1, 2, 3) , Long H. B. Nguyen (1, 4, 2) , Emmanuel Petit (1, 2) , Paula Sanz Camacho (1) , Christian Masquelier (4, 2, 3) , Dany Carlier (1, 2, 3) , Laurence Croguennec (1, 2, 3)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 RS2E - Réseau sur le stockage électrochimique de l'énergie
3 ALISTORE-ERI - Advanced Lithium Energy Storage Systems - ALISTORE-ERI
4 LRCS - Laboratoire réactivité et chimie des solides - UMR CNRS 7314

Polyanionic Na3V2(PO4)2FO2 has been successfully prepared for the first time by ionothermal reaction in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMIM TFSI) ionic liquid. Its structure and elemental stoichiometry are confirmed by X-ray diffraction, NMR spectroscopy, and ICP-OES, respectively. Furthermore, the scanning electron microscopy reveals that the as-obtained material possesses an original platelet-like morphology. A topochemical reaction mechanism is proposed to explain the formation of the 3D framework of Na3V2(PO4)2FO2 from layered compound α-VOPO4·2H2O. Galvanostatic electrochemical tests indicate a modification of the desodiation and sodiation mechanism of the as-prepared Na3V2(PO4)2FO2 compared to those synthesized by conventional solid-state approaches. Furthermore, the electrochemical performance of Na3V2(PO4)2FO2 obtained at different cycling rates is also discussed.

Domaines: Matériaux

Jacob Olchowka, Long H. B. Nguyen, Emmanuel Petit, Paula Sanz Camacho, Christian Masquelier, et al.. Ionothermal synthesis of polyanionic electrode material Na3V2(PO4)2FO2 through a topotactic reaction. Inorganic Chemistry, 2020, 59 (23), pp.17282-17290. ⟨10.1021/acs.inorgchem.0c02546⟩. ⟨hal-03028092⟩