Sodium-ion　batteries　are　a　very　promising　alternative　to　lithium-ion　batteries　because　of　their　reliance　on　an　abundant　supply　of　sodium　salts,　environmental　benignity,　and　low　cost.　However,　the　low　rate　capability　and　poor　long-term　stability　still　hinder　their　practical　application.　A　cathode　material,　formed　of　RuO2-coated　Na3V2O2(PO4)(2)F　nanowires,　has　a　50nm　diameter　with　the　space　group　of　I4/mmm.　When　used　as　a　cathode　material　for　Na-ion　batteries,　a　reversible　capacity　of　120mAhg(-1)　at　1C　and　95mAhg(-1)　at　20C　can　be　achieved　after　1000　charge-discharge　cycles.　The　ultrahigh　rate　capability　and　enhanced　cycling　stability　are　comparable　with　high　performance　lithium　cathodes.　Combining　first　principles　computational　investigation　with　experimental　observations,　the　excellent　performance　can　be　attributed　to　the　uniform　and　highly　conductive　RuO2　coating　and　the　preferred　growth　of　the　(002)　plane　in　the　Na3V2O2(PO4)(2)F　nanowires.