A porous N-doped carbon aggregate as sulfur host for lithium-sulfur batteries

Lithium-sulfur batteries have been regarded as one of the most prospective energy storage systems due to low cost and high energy density. However, the inferior cycle stability mainly due to the dissolution of polysulfides seriously restricts its practical application. Herein, a porous N-doped carbon nanofiber/carbon nanotube aggregate is obtained through the chemical oxidation combined with chemical vapor deposition method for lithium-sulfur batteries. The favorable microstructure and configuration exhibit good ability of localizing and retaining dissolved intermediate polysulfides through the in situ growth of carbon nanotube bushes on the carbonized polyaniline (PANI) nanofiber. Moreover, the three-dimensional conductive carbon as a matrix facilitates the electron transfer and reversible electrochemical reaction of active materials during cycling. This advantageous structure exhibits excellent electrochemical performance with high initial discharge capacity of 1018 mA h g−1 and stable capacity of 591 mA h g−1 at 1 C after 500 cycles.