Enhanced structural, electrochemical and electrode kinetic properties of Na0.5Ni0.2Mg0.1Mn0.7O2 material for sodium-ion battery application

The hybrid P3/P2-structured Na0.5Ni0.3Mn0.7O2 as a cathode material for sodium-ion batteries (SIBs) demonstrates high initial discharge capacity. But the existence of unstable P3 phase leads to the fast capacity fade that is adverse to engineering application. Herein, the introduction of inactive magnesium to partially replace electrochemically active nickel of the Na0.5Ni0.3Mn0.7O2 is proposed to reinforce the structural stability of the material. It is found that magnesium incorporation can suppress the growth of P3 phase, and proper substitution of magnesium for nickel can even heavest pure P2 phase material. The XRD pattern reveals that the prepared Na0.5Ni0.2Mg0.1Mn0.7O2 (Mg-0.1) is structure-stable P2-type material. The fabricated Na0.5Ni0.2Mg0.1Mn0.7O2 SIB cathode exhibits acceptable initial discharge capacity, tunable rate capability, and satisfactory cycling stability. These superior electrochemical properties are accounted for low electrochemical resistances, fast Na+ diffusion kinetics, and ext...