Long-Life, High-Efficiency Lithium–Sulfur Battery from a Nanoassembled Cathode

Lithium–sulfur (Li–S) batteries suffer from major problems including poor cycle performance and low efficiency, mainly due to the high solubility of intermediate polysulfides and their side-reactions with the Li-anode. Here, we report the development of advanced, multilayered, sulfur cathodes composed of alternately arranged, negatively charged S-carbon nanotube layers and positively charged S-polyaniline layers that effectively immobilize polysulfides and reduce polysulfide migration onto the Li-anode. The use of a layer-by-layer nanoassembly technique leads to a binder-free, three-dimensional porous cathode via electrostatic attraction and enables the fabrication of Li–S cells with remarkably improved performance including a long cycle life exceeding 600 cycles and a high Coulombic efficiency of 97.5% at the 1 C rate. Moreover, these Li–S cells have presented a high-rate response up to 2.5 C with high sulfur utilization (a reversible capacity of 1100 mAhg–1, 900 mAhg–1, 700 mAhg–1, and 450 mAhg–1 of sulfur at 0.3, 0.6, 1, and 2.5 C rates, respectively). The results provide important progress toward the understanding of the role of multilayered cathodes and the realization of high-efficiency and long-term service life for Li–S batteries.