摘要
以具有菱形十二面体结构的ZIF-67为模板,采用两步烧结法合成了CoSe_(2)/C复合材料,CoSe_(2)纳米颗粒直径约30 nm,均匀分散在碳骨架上.电化学测试结果表明,CoSe_(2)/C复合材料在放电过程中可以加快可溶性聚硫离子的还原反应动力学,还能够促进不溶性Li_(2)S的沉积过程,同时加速充电过程中Li_(2)S的氧化分解.将CoSe_(2)/C作为电催化材料与碳材料混合后用于隔膜修饰,修饰层面载量仅为0.15 mg/cm^(2),其中CoSe_(2)/C的质量分数仅占30%时,电池依然表现出优异的电化学性能;当硫载量为4.8 mg/cm^(2)时,在0.2C倍率下电池初始放电比容量为756 m A·h/g,经过180次循环后,容量依然能够维持715 mA·h/g,每次衰减率仅为0.031%.
Herein,CoSe_(2)/C composite was obtained by a simple two-step calcining method with the rhombohedral dodecahedral ZIF-67 as the template.The CoSe_(2) nanoparticles with diameters of approximately 30 nm were dispersed in the carbon skeleton maintaining the structure of the template.Systematically electrochemical results demonstrated that the CoSe_(2)/C composite could fasten the kinetics of the soluble lithium polysulfides,as well as guide the deposition of the insoluble Li_(2)S during the discharge process.In addition,the CoSe_(2)/C could also boost the oxidation of Li_(2)S.It was loaded on commercial Celgard 2400 separators as the electrocatalytic materials.It is worth to note that the mass loading of the modified layer is only 0.15 mg/cm^(2),in which the CoSe_(2)/C composite only accounts for 30%(mass frac⁃tion).Consequently,the cells with CoSe_(2)/C-modified separator delivered a superior electrochemical performance,which with a high sulfur loading of 4.8 mg/cm^(2) gave an initial specific capacity of 756 mA·h/g at 0.2C and maintained at 715 mA·h/g after 180 cycles,with a capacity decay rate of 0.031%per cycle.
作者
韩付超
李福进
陈良
贺磊义
姜玉南
徐守冬
张鼎
其鲁
HAN Fuchao;LI Fujin;CHEN Liang;HE Leiyi;JIANG Yunan;XU Shoudong;ZHANG Ding;QI Lu(College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,China;College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China)
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第8期183-191,共9页
Chemical Journal of Chinese Universities
基金
国家自然科学基金(批准号:21706171,21606158,21978193)资助。
关键词
锂硫电池
电催化
硒化钴
隔膜修饰
穿梭效应
Li-S battery
Electrocatalysis
CoSe_(2)
Modified separator
Shuttle effect
