High Entropy Boosts the Low Temperature Na + ‐Storage Performance of Na 4 Fe 3 (PO 4 ) 2 P 2 O 7

Abstract Na 4 Fe 3 (PO 4 ) 2 P 2 O 7 (NFPP) is considered a promising cathode material for sodium ion batteries (SIBs). However, the inferior electronic conductivity and inadequate Na + ions diffusion kinetics of NFPP at low temperatures hinder its practical applications. In this study, high entropy Na 4 Fe 2.95 (MgCaAlCrMn) 0.01 (PO 4 ) 2 P 2 O 7 (HE‐NFPP) has been synthesized via a spray‐drying and high temperature sintering technique. The incorporation of transition metal (TMs) ions into NFPP through HE strategy facilitates electron transportation by reducing the bandgap between the conduction and valence bands. Meanwhile, the 3D network Na + ions diffusion channels formed in HE‐NFPP can effectively improve…