Optimized synthesis of Na2/3Ni1/3Mn2/3O2 as cathode for sodium-ion batteries by rapid microwave calcination

Microwave calcination is proposed as an alternative route to conventional heating to prepare layered P2–Na2/3Ni1/3Mn2/3O2 as a positive electrode for sodium-ion batteries. The sample obtained by the fastest conditions, with a heating ramp of 20 °C min−1 for only 2 h, showed well-crystallized rounded particles. Cyclic voltammetry and impedance spectroscopy evidenced a low internal cell resistance, and high diffusion coefficients, which justify its capability to sustain the highest capacity at 1 C and retain the discharge capacity for at least two hundred cycles.