by their high cost and insufficient lithium resources. [2] As sodium is abundant and shows similar physicochemical properties to lithium, sodium ion batteries (SIBs) have been recognized as a cost effective alternative for applications in ESSs; [3] thus, extensive research studies have been devoted to develop high-performance electrode materials for SIBs. To date, ample potential cathode materials for SIBs have been proposed. [4] As for anode, carbonaceous materials, [5] phosphorus, [6] alloy, [7] and metal oxides [8] have been exploited as potential SIB anode materials. Carbon anodes are considered as the most promising choice for commercialization, owing to their low cost and environmentally benign nature. However, slow ion diffusion kinetics and significant volume changes, resulting from larger ionic radius of sodium than that of lithium, lead to poor rate and cycling performance and hinder the practical application of most carbon anode materials. [9] Considering the intermittence and fluctuation nature of renewable energy and the economic viability for ESSs, developing suitable anode materials with fast sodium storage properties and long-term cycle stability is a crucial issue for SIBs. [10] To enhance the electrochemical performance of carbonaceous anodes, a number of strategies have been proposed. Nanostructure construction has been considered as an effective method, and hollow carbon spheres have been demonstrated to be an attractive morphology for carbon materials due to their high surface area and short sodium ion diffusion path, which are kinetically favorable for ion and electron transports. [11] Besides, doping heteroatoms into carbon has been recognized as a mean to modify carbon structure, as well as to enhance electronic conductivity and wettability of carbon, thus improving electrochemical performance. [12] Maier and co-workers have first prepared hollow carbon spheres, which exhibited 160 mA h g −1 under 100 mA g −1 over 100 cycles, and 50 mA h g −1 under 10 A g −1 .[11a] Ye et al. have prepared hollow carbon spheres with sulfur and nitrogen codoping, which exhibited 169 mA h g −1 under 500 mA g −1 over 2000 cycles and 110 mA h g −1 under 10 A g −1 .[11b] However, further research on carbon-based SIB anodes with ultralong cycle life under high current density, which are essential for the grid electricity storage, is still needed. In addition, previous research studies mainly focused on perfect spheres without large pores on the surface, which would limit the electrolyte diffusion into the Carbon materials have attracted significant attention as anode materials for sodium ion batteries (SIBs). Developing a carbon anode with long-term cycling stability under ultrahigh rate is essential for practical application of SIBs in energy storage systems. Herein, sulfur and nitrogen codoped mesoporous hollow carbon spheres are developed, exhibiting high rate performance of 144 mA h g −1 at 20 A g −1 , and excellent cycling durability under ultrahigh current density. Interestingly, during 7000 cyc...
