In this work, to improve the cyclability and high-temperature performance of cubic spinel LiMn2O4 (LMO) as cathode materials, Nb5+-doped LiMn2O4 powders coated and uncoated with Al2O3 and/or B2O3 were synthesized via the modified solid-state reaction method. It was found that Nb5+-doped and B2O3 + Al2O3-coated LMO powders comprising 5 mm granular agglomerated fine primary particles smaller than 350 nm in diameter exhibited superior electrochemical properties with initial discharge capacity of 101.68 mA h g(-1); we also observed capacity retention of 96.31% after 300 cycles at room temperature (RT) and that of 98% after 50 cycles at 55 degrees C and 1C rate.