This　work　reports　on　the　optimized　preparation　of　a　series　of　composites　xLi(2)MnO(3)center　dot(1-x)LiMn1/3Ni1/3Co1/3O2　(x　=　0.1-0.4)　with　an　aim　to　find　an　advanced　high-voltage　cathode　for　lithium-ion　batteries　that　can　work　at　elevated　temperatures.　Developing　a　two-step　molten-salt　method　leads　to　composites　with　a　layered-type　structure,　showing　a　particle　size　distribution　ranging　from　350　to　450　nm.　The　composites　are　featured　by　oxidation　states　stabilized　as　Mn4+,　Ni2+,　and　Co3+,　and　by　lattice　occupation　of　Li+　in　both　transition-metal　layers　and　lithium　layer　of　LiMn1/3Ni1/3CO1/3O2.　When　acting　as　a　cathode　of　lithium-ion　batteries,　the　composite　at　x　=　0.3　shows　an　optimum　electrochemical　performance　as　characterized　by　a　discharge　capacity　of　120　mAh　g(-1)　at　a　high　current　density　of　500　mA　g(-1)　and　a　capacity　retention　of　64%　after　20　cycles.　Surprisingly,　this　electrochemical　performance　is　significantly　improved　at　elevated　temperatures.　Namely,　discharge　capacity　is　increased　to　140.4　mAh　g(-1)　at　a　high　current　density　of　500　mA　g(-1),　while　average　capacity　decay　rate　becomes　very　small　to　0.76%.　These　excellent　performance　is　explained　in　terms　of　the　dramatically　improved　lithium-ion　diffusions　in　both　electrode　and　surface　films　at　elevated　temperatures.　(c)　2012　Elsevier　Ltd.　All　rights　reserved.