Li-rich　layered　oxides　(LLOs)　suffer　from　rapid　voltage　decay　and　capacity　fading,　greatly　hindering　their　applications　as　high-energy　cathode　materials　for　Li-ion　batteries　(LIBs),　which　are　closely　associated　with　irreversible　structural　transformation　and　lattice　oxygen　loss　upon　electrochemical　cycling.　A　strategy　of　Al/Ti　synergistic　bulk　doping　is　proposed　to　stabilize　LLOs　against　structural　degradations,　yielding　remarkable　electrochemical　performance　including　a　minor　voltage　decay　of　0.34　mV　cycle(-1)　and　a　superior　capacity　retention　of　89.7%　over　500　cycles　at　1C.　The　improved　structural　stability　of　Al/Ti　codoped　LLOs　is　well　maintained　after　not　only　initial　but　also　long　cycles.　This　effect　can　be　attributed　to　the　cooperation　of　Al　and　Ti,　with　the　former　stabilizing　the　lattice　oxygen　by　strong　Al-O　bonds　and　the　latter　improving　the　Li+　conductivity　by　expanding　the　lattice.　The　facile　bulk　synergistic　doping　of　LLOs　paves　avenues　toward　their　application　for　high-energy　LIBs.