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多孔生物质碳硫复合正极材料的制备及其电化学性能研究

发表时间:2018-10-15  浏览量:97  下载量:31
全部作者: 吴雨亭,葛海涛,苗铭,陆宏斌,胡羽妙,陈曼芳,王先友
作者单位: 湘潭大学化学学院
摘 要: 理论比容量高达1 675 mAh/g、质量比能量可达2 600 Wh/kg的锂硫电池,被认为是新一代最具竞争力的二次电池之一。但单质硫存在“穿梭效应”,因此考虑加入高导电性的基体以提高活性利用率。鉴于传统碳基材料昂贵的成本因素,本文以废弃莲杆为原料制备导电性较高的多孔生物质碳材料,通过简单的高温热解法和KOH活化法制得活化莲杆碳材料(activated lotus carbon,ALC),并与单质硫形成活化碳硫复合材料(ALC/S)。利用扫描电子显微镜(scanning electron microscope,SEM)、透射电子显微镜(transmission electron microscope,TEM)、X射线衍射(X-ray diffraction,XRD)对复合材料进行形貌、结构分析。结果表明,制得的活化莲杆碳材料比表面积为2 966 m2/g,平均孔径为2.697 nm,具有强物理吸附作用以显著抑制多硫化物的溶解和扩散。电化学测试显示,0.2 C倍率下ALC/S电极首次放电比容量高达1 358 mAh/g,硫的利用率达到了81%,循环50次后比容量仍保持在1 064 mAh/g,较之普通锂硫电池其电化学性能得到了显著改善。
关 键 词: 物理化学;锂硫电池;正极材料;生物质碳
Title: Study on preparation and electrochemical performance of porous biomass carbon/sulfur composite cathode materials
Author: WU Yuting, GE Haitao, MIAO Ming, LU Hongbin, HU Yumiao, CHEN Manfang, WANG Xianyou
Organization: School of Chemistry, Xiangtan University
Abstract: Lithium-sulfur (Li-S) batteries are nominated as one of the most promising next-generation storage battery due to its high theoretical specific capacity (1 675 mAh/g) and energy density (2 600 Wh/kg). However, some problems such as the shuttle effect necessitate the addition of high conductivity matrices, which are usually high cost, to enhance the active-material utilization. In this paper, the activated lotus carbon (ALC) is fabricated by high temperature pyrolytic cracking bio-waste lotus and activating the material with KOH, which prepared activated lotus carbon/sulfur composite (ALC/S) with sulfur. The morphology and structure of the composites are characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD). Results show that the as-prepared ALC possesses a large specific surface area of 2 966 m2/g and an average pore size of 2.697 nm, introducing strong physical adsorption to significantly suppress the dissolution and diffusion of polysulfide. Herein, the cathode exhibits a high initial discharge capacity of 1 358 mAh/g at 0.2 C and the fraction of utilized sulfur reaches up to 81%, and reversible capacity remains 1 064 mAh/g after 50 cycles at 0.2 C, which means it has obviously enhanced the electrochemical performance than ordinary Li-S battery.
Key words: physical chemistry; lithium-sulfur batteries; cathode material; biomass carbon
发表期数: 2018年10月第19期
引用格式: 吴雨亭,葛海涛,苗铭,等. 多孔生物质碳硫复合正极材料的制备及其电化学性能研究[J]. 中国科技论文在线精品论文,2018,11(19):1977-1984.
 
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