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Abstract Na-superionic conductor-structured Na 3 V 2 (PO 4) 3 is extensively investigated as a promising cathode material for sodium-ion batteries. Unfortunately, the Na 3 V 2 (PO 4) 3 cathode suffers from low rate capability due to its inherent low electric conductivity. One of the general solutions to this dilemma is to embed the Na 3 V 2 (PO 4) 3 nanoparticles uniformly within carbon matrix, however, the effect of carbon matrix categories on the sodium storage performance of Na 3 V 2 (PO 4) 3 is unclear. Here we systematically compare the influence of different carbon matrix on the electrochemical properties of the Na 3 V 2 (PO 4) 3 cathode and find that expanded graphite outperforms carbon nanotubes and carbon black as carbon matrix. As a result, the as-synthesized Na 3 V 2 (PO 4) 3 /expanded graphite composite delivers a high reversible capacity of 111.4 mAh g−1 at 1C, superior rate capability (105 mAh g−1 at 50C), and ultralong cycle life (48 mAh g−1 after 20,000 cycles at 50C), which are better than most Na 3 V 2 (PO 4) 3 -based composites reported previously. Moreover, the remarkable electrochemical performance of Na 3 V 2 (PO 4) 3 /expanded graphite in symmetric cells further advances the practical application of sodium-ion batteries. Graphical abstract Image 1 Highlights • NVP/C composites are synthesized by freeze drying, ball milling, and annealing. • A systematic study of the influence of different carbon matrix are carried out. • Excellent rate capability and ultralong cycle life are demonstrated by NVP/EG. • Superior electrochemical properties of NVP/EG in symmetric cells are revealed. [ABSTRACT FROM AUTHOR]