Na-Fe-P Stoichiometry-Driven Heterostructure Design With a P2O7-Rich Buffering Phase for Stable NASICON-Type Sodium-Ion Cathodes.
Na4Fe3(PO4)2P2O7 (NFPP) is a NASICON-type iron-based polyanionic cathode that is attracting increasing interest for sodium-ion batteries because of its low cost, robust framework, three-dimensional Na+ transport channels, and high operating voltage. However, its electrochemical performance is severely compromised by th...