Dispersion of conductive carbon allotropes inside Na2FePO4F particles by spray-drying

Among all phosphate based compounds, Na2FePO4F (NFPF) is identified as a promising low-cost material for Li and Na-ion batteries [2]. Beside a relatively high voltage (3.6 V vs. Li+/Li0), Na2FePO4F exhibits a good theoretical capacity (~135 mAh/g) and an excellent stability of the structure during the intercalation process. However, despite these powerful advantages, the main drawback of Na2FePO4F cathode material is its low conductivity leading to mediocre cycling performance. The aim of this work is to enhance the electronic conductivity of Na2FePO4F particles by addition of carbon nanotubes (CNT) or carbon black (CB) during the spray-drying synthesis [3]. The structural, electrochemical and morphological properties of the synthesized Na2FePO4F-xCB and Na2FePO4F-xCNT (x = wt% of carbon) were investigated by various techniques in order to compare the effect of CB and CNT.