Nb-doped and Al 2 O 3 + B 2 O 3 -coated granular secondary LiMn 2 O 4 particles as cathode materials for lithium-ion batteries.

In this work, to improve the cyclability and high-temperature performance of cubic spinel LiMn 2 O 4 (LMO) as cathode materials, Nb 5+ -doped LiMn 2 O 4 powders coated and uncoated with Al 2 O 3 and/or B 2 O 3 were synthesized via the modified solid-state reaction method. It was found that Nb 5+ -doped and B 2 O 3 + Al 2 O 3 -coated LMO powders comprising 5 μm 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 °C and 1C rate.