Nickel-rich　layered　oxides　(LiNixCoyMn1-x-yO2,　x≥0.8,　NCM)　are　the　most　promising　cathode　material　for　next-generation　high-energy　batteries　owing　to　their　low　production　cost,　high　specific　capacity　and　high　operating　voltage.　However,　the　practical　deployment　of　high-voltage　NCM　cathodes　is　still　plagued　by　mechanical　failure　of　NCM　secondary　particles　due　to　the　internal　strain　accumulation　and　particle　crack　during　(de)lithiation.　Herein,　we　report　a　convenient　coprecipitation　strategy　to　introduce　gradient　porous　structure　into　the　polycrystalline　NCM　secondary　particles.　Through　multistage　micro-　and　nanostructural　tailoring　from　hydroxide　precursor　in　coprecipitation　process　to　the　lithiated　oxide　during　the　lithiation　stage,　which　refers　to　optimal　engineering　of　the　precursor　micro-　and　nano-structure　by　introducing　extra　organic　polymer　(polystyrene-acrylonitrile　copolymer)　as　heterogeneous　nucleation　seeds　and　alkyl　diphenyl　ether　disulfonate　disodium　as　dispersants,　we　optimize　the　primary　particle　morphology　containing　nano-voids　and　secondary　particle　containing　gradient　porous　structure　of　the　cathode.　Through　high-resolution　aberration-corrected　scanning　transmission　electron　microscopy　and　scanning　electron　microscopy,　the　detailed　gradient　porous　structure　of　the　as-obtained　nickel-rich　layered　oxide　cathode　is　clarified,　and　the　formation　of　gradient　porous　structure　is　attributed　to　the　rapid　diffusion　of　the　carbonized　organic　matter　by　the　calcination　treatment　under　oxygen　atmosphere　during　the　lithiation　stage.　This　gradient-porous-structured　nickel-rich　layered　oxide　cathode　can　mitigate　the　anisotropic　volume　change　of　the　primary　particles,　suppress　intergranular/intragranular　cracks　and　limit　impedance　growth　effectively.　The　as-obtained　cathode　exhibits　high　specific　capacity　of　180.1　mAh•g−1　(1　C,　25　℃)　and　capacity　retention　of　87.6%　after　300　cycles　even　charged　to　a　high　cut-off　voltage　of　4.5　V.　Moreover,　this　cathode　presents　enhanced　high　reversible　capacity　and　cycling　stability　in　a　wide　temperature　range　of　－20～60　℃.　This　study　suggests　the　gradient　porous　structure　design　can　homogenize　stress　distribution　and　mitigate　volumetric　change,　representing　a　promising　pathway　to　tackle　the　structural　instability　upon　high-voltage　cycling.　©　2024　Shanghai　Institute　of　Organic　Chemistry,　Chinese　Academy　of　Sciences.