A Polyaniline-Coated Sulfur/Carbon Composite with an Enhanced High-Rate Capability as a Cathode Material for Lithium/Sulfur Batteries
A Polyaniline-Coated Sulfur/Carbon Composite with an Enhanced High-Rate Capability as a Cathode Material for Lithium/Sulfur Batteries
复制标题
具有增强高倍率性能的聚苯胺涂层硫/碳复合材料作为锂/硫电池正极材料
DOI：
10.1002/aenm.201200017
复制
发表时间：
2012-10-01
影响因子：
27.8
通讯作者：
Gao, Xue-Ping
中科院分区：
文献类型：
--
作者：
Li, Guo-Chun;Li, Guo-Ran;Gao, Xue-Ping
将导电炭黑和升华硫通过球磨和热处理，然后在过硫酸铵存在下进行苯胺单体的原位化学氧化聚合，制备了不同硫含量的聚苯胺包覆硫/导电炭黑（PANI@S/C）复合材料。系统研究了复合材料的微观结构和电化学性能。结果表明，聚苯胺以约510 nm的厚度均匀包覆在S/C复合材料表面，形成核/壳结构。硫含量为43.7wt%的PANI@S/C复合材料具有最佳的电化学性能，包括大的可逆容量、良好的库仑效率和高的活性硫利用率。PANI@S/C复合材料中独特的核/壳结构的形成是其电化学性能提高的主要原因。特别是，由于基体中的导电炭黑和表面上的PANI对高导电性的协同效应，PANI@S/C复合材料的高倍率充电/放电能力是优异的。在10C倍率下，活化后的PANI@S/C复合材料的最大放电容量仍为635.5mA·h/g硫，200次循环后的放电容量保持率仍在60%以上。
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 approximate to 510 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.