The　oxygen　redox　reaction　in　lithium-rich　layered　oxide　battery　cathode　materials　generates　extra　capacity　at　high　cell　voltages　(i.e.,　＞4.5　V).　However,　the　irreversible　oxygen　release　causes　transition　metal　(TM)　dissolution,　migration　and　cell　voltage　decay.　To　circumvent　these　issues,　we　introduce　a　strategy　for　tuning　the　Coulombic　interactions　in　a　model　Li-rich　positive　electrode　active　material,　i.e.,　Li1.2Mn0.6Ni0.2O2.　In　particular,　we　tune　the　Coulombic　repulsive　interactions　to　obtain　an　adaptable　crystal　structure　that　enables　the　reversible　distortion　of　TMO6　octahedron　and　mitigates　TM　dissolution　and　migration.　Moreover,　this　strategy　hinders　the　irreversible　release　of　oxygen　and　other　parasitic　reactions　(e.g.,　electrolyte　decomposition)　commonly　occurring　at　high　voltages.　When　tested　in　non-aqueous　coin　cell　configuration,　the　modified　Li-rich　cathode　material,　combined　with　a　Li　metal　anode,　enables　a　stable　cell　discharge　capacity　of　about　240　mAh　g(-1)　for　120　cycles　at　50　mA　g(-1)　and　a　slower　voltage　decay　compared　to　the　unmodified　Li1.2Mn0.6Ni0.2O2.　Tailoring　the　oxygen　redox　reactivity　in　Li-rich　cathode　is　crucial　for　developing　high-energy　batteries.　Here,　the　authors　report　a　strategy　to　obtain　a　flexible　crystal　structure　and　enhance　the　oxygen　redox　reversibility.