AgNbO3　antiferroelectric　(AFE)　ceramics　have　attracted　much　attention　because　of　their　high-energy　storage　performance　and　environment-friendly　characteristics.　In　this　paper,　Sb2O5-doped　AgNbO3　ceramics　are　prepared　by　the　traditional　solid-state　reaction　method,　and　the　effects　of　phase　structure,　microstructure,　dielectric,　and　ferroelectric　properties　are　systematically　investigated.　Lattice　shrinkage　and　obvious　grain　size　change　are　caused　by　the　introduction　of　Sb5+　ions.　The　dielectric　constant　increases　significantly　with　the　introduction　of　Sb5+　(εr　from　210　to　550　at　room　temperature),　and　the　phase　transition　temperatures　of　M1–M2　and　M2–M3　shift　to　a　lower　temperature　as　the　Sb-doping　level　increases.　High　relaxor　degree　γ　=　1.97　of　M1–M2　peak　is　achieved　in　the　AgNb0.98Sb0.02O3　ceramics,　showing　typical　relaxor　antiferroelectric　characteristics.　Simultaneously,　the　relaxor　characteristics　lead　to　lower　remanent　polarization　values,　a　finer　P–E　hysteresis　loop,　and　an　improved　AFE　phase　in　AgNb0.98Sb0.02O3　ceramics.　Compared　to　pure　AgNbO3,　AgNb0.98Sb0.02O3　ceramics　have　a　higher　recoverable　energy　density　(Jrec=　1.70 J/cm3)　and　higher　energy　efficiency　(η　=　30.05%).　©　2023,　The　Author(s),　under　exclusive　licence　to　Springer　Science+Business　Media,　LLC,　part　of　Springer　Nature.