XPS and Raman study of spray-dried Na3V2(PO4)2F3/C as cathode material for sodium ion batteries

Na3V2(PO4)2F3 (NVPF) has attracted much attention as cathode material for Na-ion batteries thanks to the inductive effects allowing for a high working potential combined with a high theoretical specific capacity due to the multiple oxidation states of vanadium [1-2]. One of the limitations of NVPF electrodes is their low intrinsic electronic conductivity; therefore, we have prepared composites of NVPF with conductive carbon sources to ensure higher electronic conductivity of the electrodes.
NVPF and NVPF/carbon composite materials were prepared by spray-drying as in our previous work [2]. Spray drying is a cost-effective and up-scalable route to prepare homogeneous multi-component powders, thus making it a suitable method to incorporate carbon in the composite powder [4].
The influence of different carbon sources on structural and morphological properties of NVPF and NVPF/carbon composite was investigated by combining several characterization techniques (XRD, SEM and TEM). The chemical composition at the surface of the powders were studied using XPS. Raman spectroscopy was used to evaluate the quality in disordered carbon materials and its electronic conductivity [3] and compare the results with the results from EIS and cycling performance of different samples.

References:
[1] Shakoor et al., Chem. 22,2012, 20535.
[2] Eshraghi et al., Electrochimica Acta, 228, 2017, 319.
[3] Mahmoud et al., J Solid State Electrochem. 22, 2018,103.
[4] Vertruyen et al., Materials 2018, 11, 1076.