Determination of the intercalation mechanism of sodium in NaLnTiO4-type materials

Titanate-based materials have attracted attention for battery applications for ongoing decades due to their low cost and ease of processing. Among these, titanium-based layered perovskite oxides (NaLnTiO4), are promising materials with initial capacities above 130 mAhg-1 at C/10 and good capacity retention on Li-ion batteries. Particularly Ln=La and Y, show reversible capacities of 130 and 160 mA h g-1, respectively. However, these materials have not yet been assessed in Na-ion batteries. Our work focuses on the study of these materials as negative electrodes (anodes) in sodium-ion batteries, where we have demonstrated reversible capacities of 120 and 100 mAhg-1 at C/10, respectively. Nonetheless, the charge storage mechanism for sodium uptake and removal in these materials is unknown. A synchrotron operando XRD study using ID11, will allow us to determine the structural changes, and Na intercalation mechanism occurring within the crystal structure, as well as their reversibility.