Na₃V₂(PO₄)₃─A Highly Promising Anode and Cathode Material for Sodium-Ion Batteries

Sodium-ion batteries may develop into a cost-efficient alternative to lithium-ion batteries. Na3V2(PO4)3/C (NVP/C) is known to be a suitable electrode material for such batteries that can be used as an anode or cathode. Here, NVP/C-based electrodes were investigated in different cell configurations. The electrodes were cycled against the anode materials hard carbon, Sb/C, SnSb/C, and sodium metal. Furthermore, NVP versus NVP was investigated. When NVP/C is cycled against the other anode materials, the cells exhibit relatively poor reliability, but in NVP–NVP cells, a high cycling stability was observed and more than 1500 cycles with a capacity retention of 80% were achieved. This work demonstrates that common problems of Na and Na-ion cells result from the anode materials used and that NVP/C itself is very reliable both as an anode and cathode material.