Lithium-ion batteries (LIBs) have changed modern life-enabling mobile communication and electric vehicles. They are the most widespread energy storage devices but they are not totally suitable for sustainable development due to the limited lithium resources in countries often with underlying political disputes. [3][4][5] As alternative candidates, sodium-ion batteries (SIBs) have drawn increasing attention by both academic and industrial communities on account of the high abundance of sodium resources. [6,7] Of great promise are inexpensive, high-energy, long-lifespan, and fast-charging SIBs in order to improve on LIBs. [8] However, a key bottleneck in commercializing SIBs is to identify competitive cathodes with long lifespan, negligible volume change, cost-effectiveness, as well as high capacity. [9][10][11] Until now, several families of cathode materials have been developed for use such as layered oxides, [12,13] Prussian blues analogs, [14] and polyanion oxides. [15][16][17] Among these, sodium superionic conductor (NASICON)-structured Na x MeMe′(PO 4 ) 3 (Me/Me′ refers to transition metals) are capable of satisfying the above requirements in terms of high ionic conductivity (3D open frameworks), limited volume change (strong Sodium super-ionic conductor (NASICON)-structured phosphates are emerging as rising stars as cathodes for sodium-ion batteries. However, they usually suffer from a relatively low capacity due to the limited activated redox couples and low intrinsic electronic conductivity. Herein, a reduced graphene oxide supported NASICON Na 3 Cr 0.5 V 1.5 (PO 4 ) 3 cathode (VC/C-G) is designed, which displays ultrafast (up to 50 C) and ultrastable (1 000 cycles at 20 C) Na + storage properties. The VC/C-G can reach a high energy density of ≈470 W h kg −1 at 0.2 C with a specific capacity of 176 mAh g −1 (equivalent to the theoretical value); this corresponds to a three-electron transfer reaction based on fully activated V 5+ /V 4+ , V 4+ /V 3+ , V 3+ /V 2+ couples. In situ X-ray diffraction (XRD) results disclose a combination of solid-solution reaction and biphasic reaction mechanisms upon cycling. Density functional theory calculations reveal a narrow forbiddenband gap of 1.41 eV and a low Na + diffusion energy barrier of 0.194 eV. Furthermore, VC/C-G shows excellent fast-charging performance by only taking ≈11 min to reach 80% state of charge. The work provides a widely applicable strategy for realizing multi-electron cathode design for high-performance SIBs.