P2-Type Na0.67Mn0.5Fe0.5O2 Synthesized by Solution Combustion Method as an Efficient Cathode Material for Sodium-Ion Batteries

P2-type sodium transition metal oxide materials have a high theoretical capacity (∼170–210 mAh g −1 ) and exhibit high sodium-ion diffusion rates. In the present work, we report P2-type Sodium layered transition metal oxide Na 0.67 Mn 0.5 Fe 0.5 O 2 material prepared by the simple solution combustion method followed by thermal treatment is studied as a promising cathode for Sodium-ion Batteries (SIBs). The formation of a pure hexagonal crystal system P2- Na 0.67 Mn 0.5 Fe 0.5 O 2 with P63/mmc phase having plate-like morphology is confirmed. The electrochemical performance of the P2- Na 0.67 Mn 0.5 Fe 0.5 O 2 as cathode for Sodium-ion Batteries shows an initial discharge capacity of ∼166 mAh g −1 with a moderate capacity retention of ∼111 mAh g −1 at a 0.1 C rate for 100 cycles. Further, the C rate performance of the material shows a reasonable capacity of >95 mAh g −1 at a 1 C rate. The slow decrease in performance during cycling of Na 0.67 Mn 0.5 Fe 0.5 O 2 cathode is due to surface reconstruction, intragranular cracks, transition metal reduction and dissolution, and electrolyte decomposition which is evident from various surface studies. The P2-Na 0.67 Mn 0.5 Fe 0.5 O 2 exhibits stable cycling and C-rate performance between 0.1C–1C which is superior to many of the literature results.