Synthesis and characterization of a crystalline Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) cathode material for sodium-ion batteries

The combustion synthesized Na 4 Fe 3 (PO 4 ) 2 (P 2 O 7 ) cathode exhibited outstanding electrochemical performance due to its higher purity, thin and dense carbon layer, and optimized pore structure compared to the one synthesized by the sol–gel method.