聚苯胺包覆的硫化锌-碳纳米管用作正极载体材料提高锂硫电池性能  

ZnS-Decorated CNTs as Backbone with Polyaniline Coating Layer to Boost the Performance Lithium-Sulfur Batteries

作　　者：周宇祥 施天宇 赵晨媛 尹海宏[1] 宋长青[1] 郁可[2] ZHOU Yuxiang;SHI Tianyu;ZHAO Chenyuan;YIN Haihong;SONG Changqing;YU Ke(School of Information Science and Technology,Nantong University,Nantong 226019,Jiangsu,China;Key Laboratory of Polar Materials and Devices,School of Physics and Electronic Science,East China Normal University,Shanghai 200241,China)

机构地区：[1]南通大学信息科学技术学院,江苏南通226019 [2]华东师范大学物理与电子科学学院,极化材料与器件教育部重点实验室,上海200241

出　　处：《材料导报》2024年第1期10-16,共7页Materials Reports

基　　金：supported by the National Natural Science Foundation of China(11974110,61974041);the ‘The Six Top Talents’ of Jiangsu Pro-vince(XCL-052);the Qing Lan Project of Jiangsu Province。

摘　　要：随着石油等化石燃料的逐渐枯竭,人们对绿色能源和电动汽车的需求持续增长,可循环的电能储存系统也得到了快速发展。然而,传统的锂离子电池已接近理论极限,因而寻找开发下一代电池电极材料受到了极大的关注。锂硫电池因为具备出色的理论比容量和能量密度、环境友好、成本低廉等优点而备受关注。然而,锂硫电池中活性硫及其放电产物导电性差、可溶性多硫化物在电极间穿梭、体积膨胀等问题导致电池的反应动力学缓慢、容量迅速下降。为了解决这些问题,有必要对硫正极进行合理设计,研究表明引入碳纳米结构(如碳纳米管、碳纳米纤维、介孔碳、石墨烯等)作为骨架负载硫能提高锂硫电池的性能。这些碳骨架具有多层次的交叠多孔结构、大比表面积和高电子迁移率等优势,为离子提供迁移通道的同时能形成物理屏障限制多硫化物的迁移,进而抑制穿梭效应改善电池的循环稳定性。但是由于碳纳米结构的非极性特点,多硫化物与碳骨架之间的相互作用较弱,只能通过物理相互作用抑制多硫化物的穿梭。为了提高抑制效果,可以将极性材料(如金属氧化物、硫化物等)与碳纳米结构进行耦合,这样就兼具了极性材料和碳纳米结构的优点。极性材料与多硫化物的相互作用较强,同时碳纳米结构的高导电性和物理屏障作用亦得以保留,因而能大幅减缓穿梭效应,提高锂硫电池的循环稳定性和倍率性能。此外,多种导电聚合物,如聚吡咯(PPy)、聚噻吩(PTh)和聚苯胺(PANI)等,亦能作为包覆层或导电载体改善锂硫电池的循环性能和倍率性能。其中聚苯胺(PANI)具有导电性高、易合成、共形性好等特点,作为包覆层能有效地防止多硫化物向外扩散,提高电子的迁移率,从而保证电池的长期循环稳定性。本工作制备了一种ZnS-CNTs/S@PANI正极材料来抑制上述缺陷,提高锂硫�Lithium-sulfur batteries(LSBs)have attracted increasing attention due to their excellent specific capacity and energy density.However,obstructions of polysulfide dissolution,the volume expansion,and the poor conductivity usually result in a significant capacity decrease and sluggish reaction kinetics during cycling.Herein,we fabricated a novel ZnS-CNTs/S@PANI cathode to suppress the aforementioned obstacles,in which the ZnS-decorated CNTs were used as backbone to support sulfur and a polyaniline(PANI)layer was then coated on them.The conductive CNT network permitted fast electron/ion transfer and meanwhile accommodated the volume expansion.The decorated ZnS quantum dots(QDs)provided abundant polar sites on CNT surface facilitating the chemisorption of polysulfides.The conductive PANI coating layer acted multiple roles as a conducting additive,an adsorbing agent,and a physical barrier,which inhibited the shuttle of polysulfides and bettered the kinetics.Therefore,the obtained ZnS-CNTs/S@PANI cathode provided a high reversible capacity of 952.33 mAh·g^(-1)at 0.5 C,and still maintained an excellent capacity of 776.37 mAh·g^(-1)even after 150 cycles.The same excellent rate performance of 633.62 mAh·g^(-1)was also obtained at 2 C.Therefore,this study provides a simple and low-cost method for the preparation of high-performance Li-S battery cathode materials.

关 键 词：锂硫电池 硫化锌 正极 聚苯胺 

分 类 号：TQ174[化学工程—陶瓷工业]