Na3V2(PO4)3 as cathode material for hybrid lithium ion batteries

Na3V2(PO4)3 of the rhombohedral NASICON structure has been prepared via solid state carbothermal reduction reaction assisted by mechanochemical activation. As a cathode material for hybrid lithium ion batteries, Na3V2(PO4)3 exhibits an initial specific discharge capacity of 114.2 mAh g−1 in the voltage range between 2.5 V and 4.6 V, with a long discharge plateau near 3.7 V versus lithium metal. Approximately 3% of the discharge specific capacity is lost over the first 3 cycles at a current rate of 0.1 C. Then, the capacity appears to stabilize with the discharge specific capacity retention of 97.4% over the following 97 cycles. The material also exhibits good rate performance. Reversible capacities of 107.0 mAh g−1 at a 1 C rate, 100.5 mAh g−1 at 5 C and 84.4 mAh g−1 at 10 C have been obtained. The preliminary results prove that Na3V2(PO4)3 is a new promising material for hybrid lithium ion batteries.

► We used the Na3V2(PO4)3 material as cathode material for hybrid lithium ion batteries for the first time. ► We introduced a mechanochemical activation assisted solid state carbothermal reduction reaction to synthesis the material. ► The product exhibited excellent cycling stability and rate performance in the hybrid ion system. ► Higher voltage plateau was exhibited than that in sodium ion batteries.