VOPO4•2H2O as a new cathode material for rechargeable Ca-ion batteries

VOPO4 center dot 2H(2)O, as a new cathode material for Ca-ion batteries, exhibits a discharge capacity of 100.6 mA h g(-1), excellent cycling stability (200 cycles) and good rate performance (42.7 mA h g(-1) at 200 mA g(-1)). In situ X-ray diffraction and in situ Raman results demonstrate the calcium-ion-storage mechanism of VOPO4 center dot 2H(2)O is a single-phase reaction based on asymmetric Ca2+ insertion and deinsertion.