A Polyaniline‐Coated Sulfur/Carbon Composite with an Enhanced High‐Rate Capability as a Cathode Material for Lithium/Sulfur Batteries |
| |
Authors: | Guo‐Chun Li Guo‐Ran Li Shi‐Hai Ye Xue‐Ping Gao |
| |
Affiliation: | Institute of New Energy Material Chemistry, Tianjin Key Laboratory of Metal and Molecule, Based Material Chemistry, Nankai University, Tianjin 300071, China |
| |
Abstract: | Polyaniline‐coated sulfur/conductive‐carbon‐black (PANI@S/C) composites with different contents of sulfur are prepared via two facile processes including ball‐milling and thermal treatment of the conductive carbon black and sublimed sulfur, followed by an in situ chemical oxidative polymerization of the aniline monomer in the presence of the S/C composite and ammonium persulfate. The microstructure and electrochemical performance of the as‐prepared composites are investigated systematically. It is demonstrated that the polyaniline, with a thickness of ≈5–10 nm, is coated uniformly onto the surface of the S/C composite forming a core/shell structure. The PANI@S/C composite with 43.7 wt% sulfur presents the optimum electrochemical performance, including a large reversible capacity, a good coulombic efficiency, and a high active‐sulfur utilization. The formation of the unique core/shell structure in the PANI@S/C composites is responsible for the improvement of the electrochemical performance. In particular, the high‐rate charge/discharge capability of the PANI@S/C composites is excellent due to a synergistic effect on the high electrical conductivity from both the conductive carbon black in the matrix and the PANI on the surface. Even at an ultrahigh rate (10C), a maximum discharge capacity of 635.5 mA h per g of sulfur is still retained for the PANI@S/C composite after activation, and the discharge capacity retention is over 60% after 200 cycles. |
| |
Keywords: | lithium/sulfur batteries sulfur cathodes polyaniline composites |
|
|