A Y-doped P2-Na0.6Li0.11Fe0.27Mn0.62O2 cathode with improved high-rate capability and cycling stability for Na-ion batteries

Abstract

P2-Na_0.6Li_0.11Fe_0.27−xMn_0.62Y_xO₂ (x = 0, 0.5%, 1%, and 2%) cathode materials were successfully prepared using a traditional solid-state method with ball milling-assisted modification. The effect of Y-doping on the crystal structure, grain size, morphology and sodium storage performance of Na_0.6Li_0.11Fe_0.27Mn_0.62O₂ was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), galvanostatic charge–discharge cycling tests, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results demonstrated that the ball-milling pre-treatment method could effectively reduce the grain size and mitigate the aggregation of Na_0.6Li_0.11Fe_0.27Mn_0.62O₂. Additionally, reasonable Y-doping (x = 1%) significantly enhances the rate capability and cycling stability of Na_0.6Li_0.11Fe_0.27Mn_0.62O₂via improving the Na⁺ diffusion kinetics and the reversibility of the oxygen redox reaction. These results indicate that Na_0.6Li_0.11Fe_0.26Mn_0.62Y_0.01O₂ is a promising candidate material for high-rate and long-life cathodes for Na-ion battery application.