The　introduction　of　Na+　is　considered　as　an　effective　way　to　improve　the　performance　of　Ni-rich　cathode　materials.　However,　the　direct　structure–property　correlation　for　Na+　doped　NCM-based　cathode　materials　remain　unclear,　due　to　the　difficulty　of　local　and　accurate　structural　characterization　for　light　elements　such　as　Li　and　Na.　Moreover,　there　is　the　complexity　of　the　modeling　for　the　whole　Li　ion　battery　(LIB)　system.　To　tackle　the　above-mentioned　issues,　we　prepared　Na+-doped　LiNi0.6Co0.2Mn0.2O2　(Na-NCM622)　material.　The　crystal　structure　change　and　the　lattice　distortion　with　picometers　precision　of　the　Na+-doped　material　is　revealed　by　Cs-corrected　scanning　transmission　electron　microscopy　(STEM).　Density　functional　theory　(DFT)　and　the　recently　proposed　electrochemical　model,　i.e.,　modified　Planck-Nernst-Poisson　coupled　Frumkin-Butler-Volmer　(MPNP-FBV),　has　been　applied　to　reveal　correlations　between　the　activation　energy　and　the　charge　transfer　resistance　at　multiscale.　It　is　shown　that　Na+　doping　can　reduce　the　activation　energy　barrier　from　ΔG　=　1.10　eV　to　1.05　eV,　resulting　in　a　reduction　of　the　interfacial　resistance　from　297　Ω　to　134　Ω.　Consequently,　the　Na-NCM622　cathode　delivers　a　superior　capacity　retention　of　90.8　%　(159　mAh.g−1)　after　100　cycles　compared　to　the　pristine　NCM622　(67.5　%,　108　mAh.　g−1).　Our　results　demonstrate　that　the　kinetics　of　Li+　diffusion　and　the　electrochemical　reaction　can　be　enhanced　by　Na+　doping　the　cathode　material.　©　2022　Elsevier　B.V.