Vanadium oxychloride as electrode material for sodium ion batteries

Layered vanadium oxychloride (VOCl) was tested as cathode material for rechargeable sodium ion batteries. Electrochemical characterization showed that the VOCl electrode can deliver a discharge capacity of 120 mAh g− 1 at a 0.5 C rate in a voltage range of 1.0-3.0 V vs Na/Na+. A capacity of 80 mAh g− 1 was obtained after 55 cycles at 1 C rate. A combination of intercalation and conversion type reaction of VOCl with Na has been identified by energy-dispersive X-ray spectroscopy (EDX) and ex situ X-ray diffraction (XRD). The results demonstrate the principle feasibility of using VOCl as cathode material for rechargeable sodium ion batteries.