Synthesis and characterization of Ru doped NaNi 0.5 Mn 0.3 Ti 0.2 O 2 cathode material with improved electrochemical performance for sodium-ion batteries

In this research, a novel layered O3-type NaNi 0.48 Mn 0.3 Ti 0.2 Ru 0.02 O 2 is fabricated by using solid-state method for sodium-ion batteries. Sodium-ion battery (SIB) can be a promising alternative to the current lithium-ion battery (LIB) technology due to the shortage of lithium in nature and higher cost. As a promising cathode material, NaNi 0.48 Mn 0.3 Ti 0.2 Ru 0.02 O 2 electrode shows a high reversible capacity of 155.3 mA h g −1 at 0.05 C (12 mA g −1 ) in the range of 1.5–4.5 V and exhibits a favorable coulombic efficiency. DFT calculation and X-ray diffraction, Raman, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy analysis are introduced to reveal the effects of substitution of Ru 4+ for Ni 2+ including the decreasing electronic localization, more stable material structure, wider sodium-ion diffusion channels and good diffusion coefficient of Na. The doping of Ru has paved a new way to enhance the electrochemical performances of O3-type cathode materials for SIBs.