Ni-rich　layered　lithiated　transition　metal　oxide　LiNi0.6Co0.2Mn0.2O2　(NCM622)　is　a　promising　candidate　for　Li-ion　batteries.　However,　the　high　nickel　content　in　NCM622　leads　to　significant　capacity　degradation　during　battery　cycling.　In　this　study,　we　investigated　the　effectiveness　of　niobium　(Nb)　doping　in　enhancing　the　performance　of　NCM622.　Our　findings　demonstrate　that　Nb-doping　reduces　cation　mixing　and　preserves　the　solid　solution　state　of　NCM622,　as　confirmed　by　calculated　formation　energy.　Furthermore,　the　introduction　of　Nb　imparts　remarkable　electrochemical　properties　to　the　material.　Even　under　high-temperature　and　high-voltage　conditions,　the　Nb-doped　sample　exhibits　significantly　improved　cycling　performance　compared　to　the　undoped　sample,　starting　from　the　fifth　cycle　onwards.　Through　a　combination　of　atomic-level　mechanisms　and　experimental　techniques,　this　research　establishes　that　Nb-doping　can　enhance　the　structural　stability　and　electrochemical　properties　of　NCM622,　providing　a　viable　pathway　for　the　industrial　advancement　of　Ni-rich　materials.　©　2023　Elsevier　Ltd