Li-rich　layered　oxide　cathode　materials　show　high　capacities　in　lithium-ion　batteries　owing　to　the　contribution　of　the　oxygen　redox　reaction.　However,　structural　accommodation　of　this　reaction　usually　results　in　O-O　dimerization,　leading　to　oxygen　release　and　poor　electrochemical　performance.　In　this　study,　we　propose　a　new　structural　response　mechanism　inhibiting　O-O　dimerization　for　the　oxygen　redox　reaction　by　tuning　the　local　symmetry　around　the　oxygen　ions.　Compared　with　regular　Li2RuO3,　the　structural　response　of　the　as-prepared　local-symmetry-tuned　Li2RuO3　to　the　oxygen　redox　reaction　involves　the　telescopic　O-Ru-O　configuration　rather　than　O-O　dimerization,　which　inhibits　oxygen　release,　enabling　significantly　enhanced　cycling　stability　and　negligible　voltage　decay.　This　discovery　of　the　new　structural　response　mechanism　for　the　oxygen　redox　reaction　will　provide　a　new　scope　for　the　strategy　of　enhancing　the　anionic　redox　stability,　paving　unexplored　pathways　toward　further　development　of　high　capacity　Li-rich　layered　oxides.　Li-rich　layered　oxide　cathodes　show　high　capacities　in　Li-ion　batteries　but　suffer　from　structural　degradation　via　O-O　dimerization.　Here,　the　authors　present　local-symmetry-tuned　Li2RuO3　with　oxygen　redox　involving　a　telescopic　O-Ru-O　configuration　avoiding　O-2　release,　enhancing　cycling　stability.