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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：1824 下载量：207
| 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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