MoO42−-mediated engineering of Na3V2(PO4)3 as advanced cathode materials for sodium-ion batteries.

A simple high-temperature solid state process is developed to prepare MoO 4 2−-doped Na 3 V 2 (PO 4) 3 (NVP-MoO 4 (x), x = 0, 0.05, 0.10, 0.15) with excellent rate capability and long cycling stability. In-situ XRD measurement reveals that the electrochemical reaction of NVP-MoO 4 (0.10) exhibits a highly reversible phase transition process. [Display omitted] • MoO 4 2−-doped Na 3 V 2 (PO 4) 3 is prepared by a simple high temperature solid-state method. • MoO 4 2− doping can propel kinetics behavior and boost electronic conductivity. • The NVP-MoO 4 (0.10) presents a superior rate and excellent cyclic performance. • In-situ XRD reveals that the electrochemical reaction of NVP-MoO 4 (0.10) exhibits a highly reversible phase transition process. Sodium vanadium phosphate [Na 3 V 2 (PO 4) 3 ] with high voltage platform, low cost and environment friendliness has been considered as one of the most promising candidates as cathodes for high-performance sodium-ion batteries. However, the sodium storage property of Na 3 V 2 (PO 4) 3 is limited because of its low electronic conductivity and poor kinetic performance. Herein, MoO 4 2−-doped Na (3+2x) V 2 (PO 4) (3-x) MoO 4(x) [NVP-MoO 4 (x), x = 0, 0.05, 0.10, 0.15] have been developed and prepared by a feasible solid-state reaction. The optimal NVP-MoO 4 (0.10) delivers a high initial capacity of 108.9 mA h g−1 and presents an excellent capacity retention of 91.5% at 1 C after 150 cycles. In addition, the NVP-MoO 4 (0.10) shows a good rate capability, delivering a relatively high capacity of 84.2 mA h g−1 at 50 C. The results of sodium storage measurement and density of states calculation indicate that MoO 4 2− doping can significantly enhance the structural stability, promote the kinetics behavior and boost the electronic conductivity of the materials. In-situ XRD test reveals that the electrochemical reaction of the NVP-MoO 4 (0.10) exhibits a highly reversible phase transition process. This work provides a new insight for the design of advanced cathodes for high-performance sodium-ion batteries by the strategy of unique anion doping. [ABSTRACT FROM AUTHOR]