Compositing pine pollen derived carbon matrix with Na 4 FeV(PO 4 ) 3 nanoparticle for cost-effective sodium-ion batteries cathode.

Na super-ion conductor type material Na3 V2 (PO4 )3 has been widely researched as the cathode of sodium-ion batteries (SIBs) in recent years, but the unsatisfying cost of Na3 V2 (PO4 )3 impedes its wide application in SIBs. In this study, iron element is used to replace part of vanadium in Na3 V2 (PO4 )3 to reduce its expense, and pine pollen is applied for the first time as a very effective carbon source to improve the performance of Na4 FeV(PO4 )3 . The fabricated composite material achieves a capacity of 105 mA h g-1 under 0.2 C and fascinating cycling stability over 94 % under 2 C for 500 cycles and 98 % under 10 C for 1000 cycles. The excellent cycle performance is caused by the involvement of pine pollen that acts as a carbon matrix to enhance the electron conductivity and block the agglomeration of active material effectively, thus the well-dispersed nano sized Na4 FeV(PO4 )3 shortens the diffusion path of sodium ion and gains a remarkable rate capability. Moreover, the distinguished reversibility during the charge and discharge procedures is ascribed also to the robust structure of Na4 FeV(PO4 )3 . This work provides an efficient route to realize the economic cathode material of SIBs with good performance.