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.