The　lead-free　(1-x)(0.8Na(0.5)Bi(0.5)TiO(3)-0.2　K0.5Bi0.5TiO3)-xBi(Mg2/3Nb1/3)O-3　ceramics　were　prepared　using　pressureless　solid-state　sintering　for　compositions　x　＜=　0.4.　At　120　degrees　C,　the　recoverable　energy　storage　density　(W-rec)　of　x　=　0.2　sample　reached　as　high　as　0.80　J/cm(3)　under　the　electric　field　of　90　kV/cm,　significantly　better　than　the　other　literature　reported　Na0.5Bi0.5TiO3　based　samples.　The　fine-grained　sample　maintained　high　insulation　resistivity　(10(11)　Omega.m　order)　from　25　degrees　C　to　200　degrees　C,　which　contributes　to　large　breakdown　electric　field　at　high　temperatures　and　leads　to　the　excellent　energy　storage　characteristics.　This　work　could　broaden　the　applications　of　Na0.5Bi0.5TiO3　based　materials　in　building　high-temperature　multi-layer　energy　storage　capacitor.　(C)　2019　Elsevier　B.V.　All　rights　reserved.