Synthesis and characterization of Ru doped NaNi0.5Mn0.3Ti0.2O2 cathode material with improved electrochemical performance for sodium-ion batteries.

In this research, a novel layered O3-type NaNi_0.48Mn_0.3Ti_0.2Ru_0.02O₂ 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_0.48Mn_0.3Ti_0.2Ru_0.02O₂ 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 Ru⁴⁺ for Ni²⁺ 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. [ABSTRACT FROM AUTHOR]