A renewable natural cotton derived and nitrogen/sulfur co-doped carbon as a high-performance sodium ion battery anode

Here we report a new N/S co-doped carbon nanosheets derived from a renewable natural cotton source and its performance as an anode for SIBs. The electrochemical testing shows that the new carbon anode outperforms other major carbon-based anodes in sodiation capacity (482.1 mAh g⁻¹ at 0.1 A g⁻¹), rate performance (375.6, 357.8, 340.5, 324.1 mAh g⁻¹ at 1.0, 2.0, 5.0 and 10.0 A g⁻¹, respectively) and cycling stability (351.1 mAh g⁻¹ at 2.0 A g⁻¹ for 600 cycles). The defects, enlarged d-spacing, reduced Na⁺ diffusion barrier and increased electronic conductivity of the fabricated N/S co-doped carbon nanosheets are responsible for the excellent Na⁺ storage property, while the pseudocapacitive behavior of Na⁺ storage contributes to their high rate performance. This work demonstrates a low-cost path forward to fabricate high-performance carbonaceous anode materials for SIBs.