Electrochemical Behavior of Some Sodium Nickel Oxides for a Sodium-Ion Battery

Sodium-ion batteries have been considered as a cheap alternative to lithium-ion batteries. Electrode materials for a sodium-ion battery and a lithium-ion battery have interesting similarities and differences in materials characteristics and electrochemical properties. Layered lithium nickel oxide, LiNiO₂ has been developed to achieve a high capacity battery, but it shows interslab cation mixing and poor thermal stability. Li₂NiO₂ has also been studied mainly as a cathode additive to compensate the lithium loss at the anode side owing to the SEI formation. It can provide a large irreversible charging capacity at the first cycle, but it exhibits a significant oxygen evolution upon charging. In this study, we report electrochemical properties of their sodium analogues for a sodium-ion battery. The materials were prepared via solid state reactions and characterized with powder XRD and SEM. Electrochemical properties of them are examined with coin half- and full-cells, and further characterized with ex-situ electrode XRD analysis. The experimental data was correlated to DFT+U calculations. Details on the materials and electrochemical properties will be presented at the meeting.