Molten salt synthesis of Li 1 + x (Ni 0.5Mn 0.5) 1 − xO 2 as cathode material for Li-ion batteries

Abstract

Li 1 + x (Ni 0.5Mn 0.5) 1 − x O 2 cathode material for Li-ion batteries has been prepared by a molten salt method using Li 2CO 3 salt. The influences of synthetic temperature and time have been intensively investigated. It is easy to obtain materials with a hexagonal α-NaFeO 2 structure except broad peaks between 20° and 25°. Nickel in Li 1 + x (Ni 0.5Mn 0.5) 1 − x O 2 is oxidized to a trivalent state while manganese maintained a tetravalent state. It is found that the discharge capacities of all samples increase with cycling. The sample prepared at 850 °C for 5 h has a discharge capacity of 130 mAh g − 1 between 2.5 and 4.5 V versus V Li+/Li at a specific current of 0.13 mA cm − 2 after 50 cycles at 25 °C.