In situ methods; Synthesis; Lithium-ion batteries; Oxyphosphates
(2015), In situ X-ray diffraction characterisation of Fe0.5TiOPO4 and Cu0.5TiOPO4 as electrode material for sodium-ion batteries, in Electrochimica Acta
, 176, 18-21.
(2015), Lithium chromium pyrophosphate as an insertion material for Li-ion batteries, in Acta crystallographica Section B, Structural science, crystal engineering and materials
, 71(Pt 6), 661-7.
(2015), Simultaneous in Situ X-ray Absorption Spectroscopy and X-ray Diffraction Studies on Battery Materials: The Case of Fe0.5TiOPO4, in Journal of Physical Chemistry C
, 119(7), 3466-3471.
(2014), Elucidation of the reaction mechanism upon lithiation and delithiation of Cu0.5TiOPO4, in Journal of Materials Chemistry A
, 2(31), 12513-12518.
(2013), Influence of cut-off potential on the electrochemistry of M0.5TiOPO4 (M = Fe, Cu) synthesized by a new route, in Journal of The Electrochemical Society
, 160(9), A1534-A1538.
Based on the very encouraging results of the previous project period, the main goal of this extension project is the design, synthesis, and characterization of a new family of oxyphosphates candidate materials for the next generation of high specific charge electrode materials for Li-ion batteries.Since the commercialization of the first Li-ion battery by Sony in the early 90’s, researchers are still looking for new materials able to offer higher density energy. Even if great improvements have been achieved in the practical specific charge of oxides and graphite, their limits are likely to be reached soon. As the need for much higher specific charge is a major challenge on the way towards electrical vehicles based on Li-ion technology, new classes of materials have to be studied. The studies carried on oxyphosphate materials have shown they were promising electrode materials with a first charge capacity higher than 450 Ah/kg.The first goal of this project is to develop a powerful tool able to combine the structure/properties data to use it as a model for the oxyphosphates family. This tool will be developed by the cross linking of different disciplines such as high quality crystallography for the structural part and the electrochemistry knowledge we already acquired on this kind of materials family. Thanks to the results obtained with the help of the structure/properties tool we will be able to understand the full reaction mechanism of different oxyphosphates (this task was already completed for the Ni0.5TiOPO4 in the previous project). We will then adapt it to a new brand of materials not yet explored electrochemically such as M0.5VOPO4 (M= Co, Ni, Cu, Fe or Mn). The main interest of replacing Ti by V is to decrease the potential window during cycling, to gain in energy density. Having at the same time the results for oxyphosphates and oxyvanadates materials will help the scientific community to understand the link between the number of electrons of the transition metal and the reaction mechanism; as such compounds have never been reported. This project should open new perspectives in the search for high specific charge electrode materials. Finally the results of the two previous tasks will allow us to design a brand new high specific charge electrode material. This “ideal” oxyphosphate will then be synthesized through a method derived from the ones used for the known compounds (solid state or soft chemistry) and depending on the nature of the elements.In short, the fact that we cannot explain the link between the entire charge capacity and the role of the transition metal for the oxyphosphate class of materials indicates that new mechanism of intercalation and/or conversion is certainly underlying it. Getting comprehension on this new mechanism will help taking the step further towards the design of better battery materials.