A low-cost and high-performance energy storage device is a key component for sustainable energy utilization. Recently, sodium (Na) ion batteries have been highlighted as a possible competitor to lithium (Li) ion batteries due to their potential merit in the cost effectiveness. Na resources are earth-abundant, and Na electrochemistry shares many similarities with Li. However, their relatively low energy/power densities and unreliable cycle stability need to be addressed. Herein, we propose a novel high-performance cathode for Na rechargeable batteries based on mass-scalable functionalized graphite nanoplatelets. This new class cathode material can deliver a high energy of ~500Whkg−1 without noticeable capacity decay after 300 cycles. Furthermore, it can retain an energy of ~100Whkg−1 at a power of ~55kWkg−1 (less than 10-s charge/discharge), which is the highest among cathodes for Na ion batteries. This transition-metal-free high-performance cathode is expected to lead to the development of low-cost and high-performance Na rechargeable batteries.