Synthesis and electrochemical properties of P2-Na2/3Ni1/3Mn2/3O2

The pure phase P2-Na2/3Ni1/3Mn2/3O2 was synthesized by a solid reaction process. The optimum calcination temperature was 850 A degrees C. The as-prepared product delivered a capacity of 158 mAh g(-1) in the voltage range of 2-4.5 V, and there was a phase transition from P2 to O2 at about 4.2 V in the charge process. The P2 phase exhibited excellent intercalation behavior of Na ions. The reversible capacity is about 88.5 mAh g(-1) at 0.1 C in the voltage range of 2-4 V at room temperature. At an elevated temperature of 55 A degrees C, it could remain as an excellent capacity retention at low current rates. The P2-Na2/3Ni1/3Mn2/3O2 is a potential cathode material for sodium-ion batteries.