Investigation of Al-doping effects on the NaFe0.5Mn0.5O2 cathode for Na-ion batteries

P2-Na2/3MO2 materials have recently been investigated as promising high-capacity cathode hosts for Na-ion batteries. On the other hand, the Na-deficiency in these materials precludes a high energy density when coupled with Na-free anodes. As an alternative, O3-NaFeO2 and its various derivatives such as NaFe0.5Mn0.5O2 have been suggested and investigated. In this study, we dope Al in NaFe0.5Mn0.5O2 and investigate Al-doping effects on the electrochemical properties of the Na+ host. The Al-doped compound shows almost the same conductivity and diffusivity as the pristine structure. However, Al-doping enhances O3-P3 phase transition.