Synthesis and electrochemical properties of a new compound, Na0.8Li0.1Ni0.31Mn0.62O2
Layered manganese-based oxide is an important cathode material for sodium ion batteries and its performance strongly depends on the composition of the material. Here we synthesize a new compound Na 0.8 Li 0.1 Ni 0.31 Mn 0.62 O 2 by a solid-state reaction method and investigate its electrochemical performance. The resultant material displays a high capacity of 138 mAh g −1 in the voltage range of 2.0-4.4 V, with good capacity retention. It also displays an excellent rate capability, by delivering a high capacity of 94 mAh g −1 at a high current density of 788.5 mA g −1 . The sodium ion diffusion coefficient of the Na 0.8 Li 0.1 Ni 0.31 Mn 0.62 O 2 is calculated to be 5.8 x 10 −12 cm 2 s −1 by AC impedance testing, which is superior to the previously reported Al-doped P2-Na 2/3 Ni 1/3 Mn 5/9 Al 1/9 O 2 compound.