Tuning the nitrogen-doping configuration in carbon materialsviasulfur doping for ultrastable potassium ion storage

We successfully achieve high-level pyridinic-N and pyrrolic-N in nitrogen-doped carbon materials, which exhibits a high reversible capacity (441.5 mA h g−1over 100 cycles at 0.1 A g−1) and long-term cycling stability (283.3 mA h g−1after 1000 cycles at 2 A g−1).