Résumé
Polyanionic materials (phosphates in particular) are of special interest as positive electrodes for Li-Ion or Na-ion batteries since they offer competitive electro-chemical performances compared to sodiated or lithiated transition metal oxides [1,2]. They are based upon stable 3D frameworks, which provide long-term structural stability and demonstrate a unique variety of atomic arrangements in their crystal structures. Recent electrochemical and structural investigations of vanadium-based phosphate compounds (LiVPO4O-LiVPO4F, Na3V2(PO4)2F3, Na3V2(PO4)3 .....) revealed promising perspectives [3-6].The NASICON structural family with its large panel of compositions, NaxMM'(PO4)3 (0 < x < 4 ; M,M' = Ti, Fe, V, Cr, Mn) is among the most widely investigated, due to its specific three-dimensional framework structure, stable long-term cycling ability and high Na+ mobility [1, 7]. Among them, the vanadium phosphate Na3V2(PO4)3 [8] is of particular interest. The crystal chemistry of these compositions is very rich and we will present several new structures that we determined, from pristine powders or for intermediate compositions spotted by operando X-Ray diffraction.By substitution of Vanadium with Aluminum, towards the new composition Na3AlV(PO4)3, a higher operating voltage is reached at 3.9 V vs. Na/Na+ for the V4+/5+ redox couple [9]. Similar phenomena were spotted for Na3FeV(PO4)3 and Na2TiV(PO4)3 [10-11]. Recently, Mn2+ was used as a substituting ion to enhance the capacity of the Na3V2(PO4)3 cathode materials [12-13]. Single phase Na4MnV(PO4)3 powders were synthesized and studied structurally and electrochemically in details. Na4MnV(PO4)3 can be charged at 156 mAh/g towards the new composition NaMnV(PO4)3 but tricky redox phenomena were spotted thanks to operando XAS spectroscopy and apparent structural irreversibility occurs when vanadium is oxidized from V4+ to V5+. Even more recently, we succeeded in synthesizing Fe-substituted Na4FeV(PO4)3 that allows the reversible extraction of close to 3 Na+ (for two transition metals). We will report on its crystal structure and on that of Na3FeV(PO4)3 for which new Na+ order-disorder phenomena have been spotted [14].[1] C. Masquelier, L. Croguennec ; Chemical Reviews, 113(8), 6552-6591 (2013)[2] P. Adelhelm, M. Casas-Cabanas, L. Croguennec, I. Hasa, A. Koposov, S. Mariyappan, C. Masquelier, D. Saurel, J. Power Sources, 482, 228872 (2021)[3] E. Boivin, J. N. Chotard, C. Masquelier, L. Croguennec, Molecules, 26(5), 1428 (2021)[4] T. Broux, F. Fauth, N. Hall, M. Bianchini, T. Bamine, J.-B. Leriche, E. Suard, D. Carlier, L. Simonin, C. Masquelier & L. Croguennec, Small Methods, 3, 1800215 (2019)[5] F. Chen, V. Kovrugin, R. David, J. N. Chotard, O. Mentré, F. Fauth & C. Masquelier, Small Methods, 3, 1800218 (2019)[6] B. Singh, Z. Wang, S. Park, G. Sai Gautam, J.N. Chotard, L. Croguennec, D. Carlier, A. K. Cheetham, C. Masquelier & P. Canepa, J. Mater. Chem. A, 9(1), 281-292 (2021)[7] C. Delmas, A. Nadiri and J. L. Soubeyroux, Solid State Ionics, 28–30, 419–423 (1988)[8] J.N. Chotard, G. Rousse, R. David, O. Mentré, C. Masquelier, Chem. Mater., 27(17),5982-5987 (2015)[9] F. Lalère, V. Seznec, M. Courty, J. N. Chotard & C. Masquelier, J. Mater. Chem. A, 3, 16198-16205 (2015)[10] F. Lalère, V. Seznec, M. Courty, J. N. Chotard & C. Masquelier, J. Mater. Chem. A, 6, 6654-6659 (2018)[11] W. Zhou; L. Xue; X. Lü; H. Gao; Y. Li; S. Xin; G. Fu; Z. Cui; Y. Zhu; J. B. Goodenough, Nano letters, 16 (12) (2016)[12] F. Chen, V. Kovrugin, R. David, J. N. Chotard, O. Mentré, F. Fauth & C. Masquelier, Small Methods, 1800218 (2018)[13] M. Zakharkin, O. Drozhzhin, I. Tereshchenko, D. Chernyshov, A. Abakumov, E. Antipov, K. Stevenson, Appl. Energy Materials, 1(11), 5842 (2018)[14] S. Park, J. N. Chotard, D. Carlier, I. Moog, M. Courty, M. Duttine, F. Fauth, A. Iadecola, L. Croguennec, C. Masquelier, Chem. Mater., submitted (2021)