Sodium Ion Storage Based on a Na_3V_2(PO_4)_3 Cathode Achieves Ultrahigh Rate Capability and Cycling Life

摘要

Due to high ionic conductivity of Na_3V_2(PO_4)_3 (NVP), stable three-dimensional structure and high theoretical capacity, NVP is attracting much attention as cathode material of Na-ion system. However, NVP has poor electronic conductivity which causes poor rate capability and cycle stability. The aim of this research is to further improve electronic conductivity and structural stability, thereby improving the rate capability and cycle stability. rGO has the characteristics of excellent electronic conductivity, large surface area, which make rGO a suitable material for the conductive network. Electrochemical tests show that NVP/rGO composites has much more excellent cycle stability and rate capability than pristine NVP. The results show that NVP/rGO can be considered as a candidate for cathode materials with high rate capability and stability in sodium ion storage systems and that forming a composite with rGO can improve rate & cycle performance of electrode materials.