用于锂硫电池的均相催化剂四氨基钴酞菁

Tetraaminocobalt phthalocyanine as a homogeneous catalyst for lithium-sulfur batteries

文章通过将四氨基钴酞菁(CoTaPc)溶解在DOL/DME电解液中构成用于锂硫电池的均相催化剂,促进可溶性多硫化锂(LiPSs)转化从而增强硫正极的反应动力学。利用紫外可见吸收光谱法、红外光谱仪、透射电子显微镜(transmission electron microscope,TEM)、循环伏安(cyclic voltammetry,CV)法和电化学阻抗谱(electrochemical impedance spectroscopy,EIS)分析CoTaPc在电解质中的添加量、稳定性和电催化活性,并进一步采用恒流充放电法研究CoTaPc对锂硫电池性能的影响。结果表明,CoTaPc是一种稳定的均相催化剂,能够有效促进LiPSs的电化学转化反应,可以使锂硫电池在0.1 C放电倍率下的首次放电比容量达到1395 mA·h/g,100次循环后容量仍保持在781 mA·h/g,库仑效率接近100%,同时放电倍率为1.0 C时的首次放电容量达到976 mA·h/g。

In this paper,tetraaminocobalt phthalocyanine(CoTaPc)was dissolved in DOL/DME electrolyte to form a homogeneous catalyst for lithium-sulfur batteries,which promoted the conversion of soluble lithium polysulfides(LiPSs)and enhanced the reaction kinetics of sulfur cathode.With the assistance of ultraviolet-visible absorption spectroscopy,infrared spectroscopy,transmission electron microscope(TEM),cyclic voltammetry(CV)and electrochemical impedance spectroscopy(EIS),the content,stability and electrocatalytic activity of CoTaPc in electrolyte were analyzed,and the constant current charge and discharge method was used to study the effect of CoTaPc on the performance of lithium-sulfur batteries.The results show that CoTaPc is a stable homogeneous catalyst that can effectively promote the electrochemical conversion reaction of soluble LiPSs.It can make the first discharge specific capacity of the lithium-sulfur battery at a discharge rate of 0.1 C reach 1395 mA·h/g.The capacity remains at 781 mA·h/g after 100 cycles,and the Coulombic efficiency is close to 100%.At the same time,the first discharge specific capacity reaches 976 mA·h/g at 1.0 C.