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 Na0.8Li0.1Ni0.31Mn0.62O2 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 Na0.8Li0.1Ni0.31Mn0.62O2 is calculated to be 5.8 × 10−12 cm2 s−1 by AC impedance testing, which is superior to the previously reported Al-doped P2-Na2/3Ni1/3Mn5/9Al1/9O2 compound.