Wu Yinbo, Feng Yaowei, Qiu Xiulian, Ren Fengming, Cen Jian, Chong Qingdian, Tian Ye, Yang Wei
School of Automation, Guangdong Polytechnic Normal University, Guangzhou 510665, China.
School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, China.
Nanomaterials (Basel). 2023 Feb 25;13(5):865. doi: 10.3390/nano13050865.
Lithium-sulfur batteries with high theoretical energy density and cheap cost can meet people's need for efficient energy storage, and have become a focus of the research on lithium-ion batteries. However, owing to their poor conductivity and "shuttle effect", lithium-sulfur batteries are difficult to commercialize. In order to solve this problem, herein a polyhedral hollow structure of cobalt selenide (CoSe) was synthesized by a simple one-step carbonization and selenization method using metal-organic bone MOFs (ZIF-67) as template and precursor. CoSe is coated with conductive polymer polypyrrole (PPy) to settle the matter of poor electroconductibility of the composite and limit the outflow of polysulfide compounds. The prepared CoSe@PPy-S composite cathode shows reversible capacities of 341 mAh g at 3 C, and good cycle stability with a small capacity attenuation rate of 0.072% per cycle. The structure of CoSe can have certain adsorption and conversion effects on polysulfide compounds, increase the conductivity after coating PPy, and further enhance the electrochemical property of lithium-sulfur cathode material.
锂硫电池具有较高的理论能量密度和低廉的成本，能够满足人们对高效储能的需求，已成为锂离子电池研究的一个热点。然而，由于其导电性差和“穿梭效应”，锂硫电池难以实现商业化。为了解决这一问题，本文以金属有机骨架材料MOFs（ZIF-67）为模板和前驱体，通过简单的一步碳化和硒化法合成了多面体中空结构的硒化钴（CoSe）。CoSe表面包覆有导电聚合物聚吡咯（PPy），以解决复合材料导电性差的问题，并限制多硫化物的流出。制备的CoSe@PPy-S复合正极在3 C时的可逆容量为341 mAh g，具有良好的循环稳定性，容量衰减率低至每循环0.072%。CoSe结构对多硫化物具有一定的吸附和转化作用，包覆PPy后提高了导电性，进一步提升了锂硫正极材料的电化学性能。
