PVP辅助水热合成钠离子电池正极材料NaV6O15及电化学性能研究

In this paper, NH4VO3 and NaCl were used to synthesize NaV6O15 nanorods via PVP-assisted hydrothermal method.The results showed the samples with pH value of 2,calcined at 400℃ and 0.1g PVP as the surfactant delivered better performance.The obtained NaV6O15 nanorods had uniform particle sizes,with an average length of 1um and width of 10um.The initial discharge capacities at the current densities of 20mA/g was 157mAh/g for potentials ranging from 1.5 to 3.8 V and yielding 121 mAh/g at a high current density of 200 mA/g, as well as the capacity retention of the sample was 79% after the 20th cycle,indicating its good cycling stability and excellent rate capability.EIS analysis results demonstrated that the diffusion coefficients DNa as higher as 2.71×10-12 cm2 s-1 at room temperature. In addition, it could be clearly observed that the NaV6O15 exhibited metallic behavior from the electron density of states, providing excellent electron conductivity. All these results suggest that NaV6O15 nanorods can be a very promising cathode for sodium batteries.