Exploration of Na7Fe4.5(P2O7)4 as a cathode material for sodium-ion batteries
A novel Na7Fe4.5(P2O7)4 compound was fabricated as a cathode for sodium-ion batteries by a mechanical milling assisted solid state method for the first time. The as-prepared material exhibits superior electrochemical performance based on half-cell testing. After uniform carbon coating, it exhibits lower electrochemical polarization, better conductivity and faster sodium ion diffusion kinetics. Benefiting from these advantages, the Na7Fe4.5(P2O7)4 was endowed with higher charge–discharge capacity, better cycle life and outstanding rate performance. The high rate capability and good cyclability of this material in non-aqueous electrolytes are advantageous for low-cost and safe battery systems.