Nitrogen/sulfur co‐doping for biomass carbon foam as superior sulfur hosts for lithium‐sulfur batteries.

Summary: To address volume expansion from active sulfur and shuttle effect from polysulfides during the electrochemical process of lithium sulfur batteries, nitrogen/sulfur co‐doping porous active carbons (NS‐PACs) derived from biomass cattail were manufactured by one‐step activated hydrothermal method. The effects of N/S atoms co‐doping and the activation of KOH on NS‐PACs were investigated in the macro‐morphology, micro‐structure, and electrochemical performance using scanning electron microscopy (SEM), X‐ray photoelectron spectroscopy (XPS), Brunauer‐Emmett‐Teller (BET), as well as galvanostatic charge/discharge tests. The experimental data demonstrated that the NS‐PACs show stable foam‐likes porous structure, and the specific surface area (SSA) and pore volumes are 2155.81 m2g−1 and 1.43 cm3g−1, respectively, and reveals perfect N/S atoms doping with S atomic content of 1.4% and N atomic content of 0.78%. Moreover, the initial discharge capacity of NS‐PACs is 1477.8 mAh g−1 at 0.1 C and the extraordinary long‐run cycling stability after 500 cycles reaches 803.4 mAh g−1 at 2.0 C. These outstanding electrochemical performances of NS‐PACs are associated with efficient physical confinement by porous architecture together with the potent chemical adsorption of N/S atoms with polysulfide. [ABSTRACT FROM AUTHOR]