Pristine Na3Fe0.5V1.5(PO4)3 and carbon-coated Na3Fe0.5V1.5(PO4)3 nano-particles are synthesized by one-step solid-phase reaction method. The full battery based on Na3Fe0.5V1.5(PO4)3@C nano-particles as cathode and commercial hard carbon as anode outputs a high working voltage about 3.3 V and exhibits superior-rate performance. While the rate increases from 0.5 to 1, 2 and 5 C, the discharge capacity of full battery slightly decreases from 110 to 94, 88, 79 mA h g−1 gradually. Moreover, it shows excellent cycle stability with a capacity retention of 93.8% after 200 cycles at 0.5 C.