Spray-dried K3V(PO4)2/C composites as novel cathode materials for K-ion batteries with superior electrochemical performance

Abstract Intensive efforts are needed to find an alternative to replace Li-ion batteries. Among the potential candidates, K-ions batteries (KIBs) have received a lot of interest thanks to the low reduction potential and low cost of potassium due to the high abundance and broad distribution of potassium sources. In this regard, the development of high performance cathode materials has raised some challenges. Phosphate-based materials are considered as the most promising cathode materials for KIBs owing to their high structural stability upon cycling, high ionic conductivity and high insertion potential. Here, K3V(PO4)2 (KVP) and K3V(PO4)2/C composites are reported as new cathode materials for KIBs with a high theoretical capacity (150 mAh.g−1) and a high working potential (3.5–4 V). The pristine KVP and KVP/C composite materials are obtained by spray-drying process. The influence of grinding process on the structural, morphological and the electrochemical properties is investigated. The composite with carbon nanotubes (KVP/20CNT) demonstrates the best reversible capacity of 101 mAh.g−1 at C/40 using 0.8 M KPF6 in PC +10 wt% FEC as electrolyte. Different characterization techniques are combined to investigate the structural and morphological properties of the materials such as XRD, SEM, TEM and Laser granulometry.