Sn　doped　lithium　nickel　cobalt　manganese　composite　oxide　of　LiNi3/8CO2/8Mn3/8-xSnxO2　(0　＜=　x　＜=　0.10)　was　synthesized　by　stannum　substitute　of　manganese　to　enhance　its　rate　capability　at　first　time.　Its　structure　and　electrochemical　properties　were　characterized　by　X-ray　diffraction　(XRD),　SEM,　cyclic　voltammetry　(CV),　galvanostatic　intermittent　titration　technique　(GITT)　and　charge/discharge　tests.　LiNi3/8CO2/8Mn3/8-xSnxO2　had　stable　layered　structure　with　alpha-NaFeO2　type　as　x　up　to　0.05,　meanwhile,　its　chemical　diffusion　coefficient　D-Li　of　Li-ion　was　enhanced　by　almost　one　order　of　magnitude,　leading　to　notable　improvement　of　the　rate　capability　of　LiNi3/8Co2/8Mn3/8O2.　The　compound　of　x　=　0.10　showed　the　best　rate　capability　among　Sn　doped　samples,　but　its　discharge　capacity　reduced　markedly　due　to　secondary　phase　Li2SnO3　and　increase　of　cation-disorder.　The　compound　with　x　=　0.05　showed　high　rate　capability　with　initial　discharge　capacity　in　excess　of　156　mAh　g(-1).　It　is　a　promising　alternative　cathode　material　for　EV　application　of　Li-ion　batteries.　(c)　2005　Elsevier　B.V.　All　rights　reserved.