Na2VSn(PO4)3: A novel NASICON-type electrode material for symmetric sodium-ion batteries

Symmetric sodium-ion batteries have so far attracted more and more attention due to the simple cell configuration, reduced volume expansion and low manufacturing cost. In this work, a novel NASICON-type compound Na2VSn(PO4)3 was successfully synthesized through sol-gel method. XRD, SEM, TEM and XPS were employed to character the material Na2VSn(PO4)3/C. The samples of Na2VSn(PO4)3/C were used not only as cathode or anode in Na||Na2VSn(PO4)3/C half cell, but also as both cathode and anode in Na2VSn(PO4)3/C||Na2VSn(PO4)3/C symmetric full cell. The results of electrochemical tests revealed that half and full cells were cycled effectively.