Sulfur confined in nitrogen-doped microporous carbon used in a carbonate-based electrolyte for long-life, safe lithium-sulfur batteries

Nitrogen-doped microporous carbon spheres (NPCSs) with a high surface area (1958 m2 g−1), large micropore volume and a high nitrogen content were synthesized by a simple one-step polymerization and subsequent ZnCl2 activation. The NPCSs can host a large number of small sulfur molecules, and restrict the reaction between the carbonate-based electrolytes and polysulfides. As a result, the NPCSs-sulfur (NPCSS) cathode exhibits excellent cyclic stability (initial capacity of 1382 mAh g−1 and 1002 mAh g−1 after 200 cycles at 0.3 C) and high rate performance (645 mAh g−1 at 3 C) even using the conventional carbonate-based electrolytes, demonstrating its potential use in long-life, safe lithium-sulfur batteries.