LiAlO2-coated LiCoO2 as cathode material for lithium ion batteries

3% LiAlO2-coated LiCoO2 and 3% Al2O3-coated LiCoO2 were prepared from C9H21O3Al, LiOH·H2O and LiCoO2 by hydrolyzing and heating technique. XRD, SEM and other various electrochemical measurement methods were used to examine these structural and electrochemical characteristics. XRD results proved that no secondary phase appeared after coating. The LiAlO2-coated LiCoO2 showed a higher specific discharge capacity (170 mA h/g at the first cycle) and an excellent cycling performance (165 mA h/g after 20 cycles) when cycled between 2.8 V and 4.5 V. Cyclic voltammograms curves indicated that LiAlO2-coating didn't suppress the phase transition from hexagonal to monoclinic. The conclusion was different from former literature's reports.