Novel transition-metal-free cathode for high energy and power sodium rechargeable batteries

Abstract

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 similar to 500W h kg(-1) without noticeable capacity decay after 300 cycles. Furthermore, it can retain an energy of similar to 100 W h kg(-1) at a power of 55 kW kg(-1) (less than 10-s charge/discharge), which is the highest among cathodes for Na ion batteries. This transition-metalfree high-performance cathode is expected to lead to the development of low-cost and high-performance Na rechargeable batteries.