S‐Doped N‐Rich Carbon Nanosheets with Expanded Interlayer Distance as Anode Materials for Sodium‐Ion Batteries

2D composites with S doping into N-rich carbon nanosheets are fabricated, whose interlayer distance becomes large enough for Na⁺ insertion and diffusion. The large surface area and stable structure also provide more sites for Na⁺ adsorption, leading to high Na-storage capacity and excellent rate performance. Moreover, Faradaic reactions between Na⁺ and tightly bound S is beneficial for further improvement of Na-storage capacity.