As　a　widely　used　approach　to　modify　a　material＇s　bulk　properties,　doping　can　effectively　improve　electrochemical　properties　and　structural　stability　of　various　cathodes　for　rechargeable　batteries,　which　usually　empirically　favors　a　uniform　distribution　of　dopants.　It　is　reported　that　dopant　aggregation　effectively　boosts　the　cyclability　of　a　Mg-doped　P2-type　layered　cathode　(Na0.67Ni0.33Mn0.67O2).　Experimental　characterization　and　calculation　consistently　reveal　that　randomly　distributed　Mg　dopants　tend　to　segregate　into　the　Na-layer　during　high-voltage　cycling,　leading　to　the　formation　of　high-density　precipitates.　Intriguingly,　such　Mg-enriched　precipitates,　acting　as　3D　network　pillars,　can　further　enhance　a　material＇s　mechanical　strength,　suppress　cracking,　and　consequently　benefit　cyclability.　This　work　not　only　deepens　the　understanding　on　dopant　evolution　but　also　offers　a　conceptually　new　approach　by　utilizing　precipitation　strengthening　design　to　counter　cracking　related　degradation　and　improve　high-voltage　cyclability　of　layered　cathodes.