High-performance lithium-sulfur battery based on porous N-rich g-C3N4 nanotubes via a self-template method

The commercial development of lithium-sulfur batteries (Li-S) is severely limited by the shuttle effect of lithium polysulfides (LPSs) and the non-conductivity of sulfur. Herein, porous g-C3N4 nanotubes (PCNNTs) are synthesized via a self-template method and utilized as an efficient sulfur host material. The one-dimensional PCNNTs have a high specific surface area (143.47 m2·g−1) and an abundance of macro-/mesopores, which could achieve a high sulfur loading rate of 74.7wt%. A Li-S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g−1. PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling. High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs. These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.