Synthesis of S/CoS2 Nanoparticles-Embedded N-doped Carbon Polyhedrons from Polyhedrons ZIF-67 and their Properties in Lithium-Sulfur Batteries

• Published in: Electrochimica acta 2016-11, Vol.218, p.243-251
• Main Authors: Zhou, Jie, Lin, Ning, Cai, Wen long, Guo, Cong, Zhang, Kailong, Zhou, Jianbin, Zhu, Yongchun, Qian, Yitai
• Format: Article
• Language: English
• Subjects: cobalt sulfides; lithium-sulfur batteries; nanoparticles; polyhedrons
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2016.09.130

[Display omitted] •S/CoS2 Nanoparticles-Embedded N-doped Carbon Polyhedrons are prepared.•The composites deliver the enhanced cycling stability in lithium-sulfur battery.•The enhanced electrochemical performance is mainly due to the synergistic effects of N-doped carbon polyhedrons and embedded CoS2. S/CoS2 nanoparticles-embedded N-doped carbon polyhedrons (S/CoS2-NC) as the cathode of lithium-sulfur battery are prepared. The synthesis is via the carbonization of metal organic frameworks polyhedron ZIF-67, followed by the heat treatment with sulfur. XRD confirms the existence of CoS2 and S, TEM shows the polyhedrons morphology and EDX mapping analysis displays the uniform distribution of Co, S and N in the carbon polyhedrons. As cathode for lithium-sulfur battery, S/CoS2-NC exhibit the enhanced cycling stability with the capacity of 702mAhg−1 at 0.5C after 250 cycles and rate performance, which is superior to S/Co nanoparticles-embedded N-doped carbon polyhedrons composites (S/Co-NC), S/N-doped carbon polyhedrons composites (S-NC) and the bare sulfur. When coupled with the Ge anode, the discharge capacity of 502mAhg−1 is obtained after 75 cycles at 0.5C. The enhanced property is mainly attributed to the synergistic effects of N-doped carbon polyhedrons and embedded CoS2.