Polyaniline-Coated Activated Carbon Aerogel/Sulfur Composite for High-performance Lithium-Sulfur Battery

An activated carbon aerogel (ACA-500) with high surface area (1765 m(2) g(−1)), pore volume (2.04 cm(3) g(−1)), and hierarchical porous nanonetwork structure is prepared through direct activation of organic aerogel (RC-500) with a low potassium hydroxide ratio (1:1). Based on this substrate, a polyaniline (PANi)-coated activated carbon aerogel/sulfur (ACA-500-S@PANi) composite is prepared via a simple two-step procedure, including melt-infiltration of sublimed sulfur into ACA-500, followed by an in situ polymerization of aniline on the surface of ACA-500-S composite. The obtained ACA-500-S@PANi composite delivers a high reversible capacity up to 1208 mAh g(−1) at 0.2C and maintains 542 mAh g(−1) even at a high rate (3C). Furthermore, this composite exhibits a discharge capacity of 926 mAh g(−1) at the initial cycle and 615 mAh g(−1) after 700 cycles at 1C rate, revealing an extremely low capacity decay rate (0.48‰ per cycle). The excellent electrochemical performance of ACA-500-S@PANi can be attributed to the synergistic effect of hierarchical porous nanonetwork structure and PANi coating. Activated carbon aerogels with high surface area and unique three-dimensional (3D) interconnected hierarchical porous structure offer an efficient conductive network for sulfur, and a highly conductive PANi-coating layer further enhances conductivity of the electrode and prevents the dissolution of polysulfide species. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s11671-017-2372-6) contains supplementary material, which is available to authorized users.