A Highly Stable Na3Fe2(PO4)3@Hard Carbon Sodium-Ion Full Cell for Low Cost Energy Storage

The abundant flake-porous Na3Fe2(PO4)3 have been prepared via a simple spray drying method. As a cathode material in sodium-ion batteries (SIBs), the galvanostatic charge-discharge test results indicate that the initial reversible discharge specific capacity of flake-porous Na3Fe2(PO4)3 electrode can reach to 100.8 mAh g-1 (about 93% the theoretical capacity of 105 mAh g-1) under a current density of 10 mA g-1 (0.1C), and the high rate capability at 500 mA g-1 (5 C) is up to 60 mAh g−1 after 1100 cycles. The in-situ X-ray diffraction pattern and ex-situ X-ray photoelectron spectroscopy test results indicate that the charge/discharge processes of this cathode material go through the reversible electrochemical reaction of Na3Fe2(PO4)3/Na5Fe2(PO4)3. The outstanding electrochemical performance of Na3Fe2(PO4)3 is attributed to its’ [Fe2(PO4)3] “lantern units” stacked NASICON-type structure and 2D sheet-porous morphology. The flake-porous Na3Fe2(PO4)3 cathode with commercial hard carbon anode full cell shows an...