高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (8): 20220163.doi: 10.7503/cjcu20220163

• 物理化学 • 上一篇    下一篇

CoSe2/C复合电催化材料修饰隔膜对高载量锂硫电池性能的影响

韩付超1, 李福进1, 陈良1(), 贺磊义1, 姜玉南1, 徐守冬1, 张鼎1, 其鲁2   

  1. 1.太原理工大学化学化工学院, 太原 030024
    2.北京大学化学与分子工程学院, 北京 100871
  • 收稿日期:2022-03-15 出版日期:2022-08-10 发布日期:2022-05-06
  • 通讯作者: 陈良 E-mail:chenliang@tyut.edu.cn
  • 基金资助:
    国家自然科学基金(21706171)

Enhance of CoSe2/C Composites Modified Separator on Electrochemical Performance of Li-S Batteries at High Sulfur Loading

HAN Fuchao1, LI Fujin1, CHEN Liang1(), HE Leiyi1, JIANG Yunan1, XU Shoudong1, ZHANG Ding1, QI Lu2   

  1. 1.College of Chemistry and Chemical Engineering,Taiyuan University of Technology,Taiyuan 030024,China
    2.College of Chemistry and Molecular Engineering,Peking University,Beijing 100871,China
  • Received:2022-03-15 Online:2022-08-10 Published:2022-05-06
  • Contact: CHEN Liang E-mail:chenliang@tyut.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21706171)

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CoSe2/C复合材料, CoSe2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, CoSe2/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Li2S的沉积过程, 同时加速充电过程中Li2S的氧化分解. 将CoSe2/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/cm2, 其中CoSe2/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/cm2时, 在0.2C倍率下电池初始放电比容量为756 mA·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%.

关键词: 锂硫电池, 电催化, 硒化钴, 隔膜修饰, 穿梭效应

Abstract:

Herein, CoSe2/C composite was obtained by a simple two-step calcining method with the rhombohedral dodecahedral ZIF-67 as the template. The CoSe2 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 CoSe2/C composite could fasten the kinetics of the soluble lithium polysulfides, as well as guide the deposition of the insoluble Li2S during the discharge process. In addition, the CoSe2/C could also boost the oxidation of Li2S. 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/cm2, in which the CoSe2/C composite only accounts for 30%(mass fraction). Consequently, the cells with CoSe2/C-modified separator delivered a superior electrochemical performance, which with a high sulfur loading of 4.8 mg/cm2 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.

Key words: Li-S battery, Electrocatalysis, CoSe2, Modified separator, Shuttle effect

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