title: In Situ Formation of Co9S8/N-C Hollow Nanospheres by Pyrolysis and Sulfurization of ZIF-67 for High-Performance Lithium-Ion Batteries.
abstract: Co9S8is considered a promising candidate as the anode material in lithium-ion batteries (LIBs) because of its remarkable electrical conductivity, high theoretical capacity, and low cost. However, the practical application of Co9S8is greatly restricted because of its poor cycling stability and rate performance, which result mainly from the large volume expansion and dissolution of the polysulfide intermediates during the charge/discharge process. In this report, Co9S8embedded in N-rich carbon hollow spheres are successfully designed and synthesized through an in situ pyrolysis and sulfurization process, employing the well-known ZIF-67 as the precursor and ethanethiol as the sulfur source. Co9S8nanoparticles embedded in the N-rich hollow carbon shell exhibit excellent lithium storage properties at a high charge/discharge rate. A discharge capacity of 784 mAh g-1is obtained upon battery testing at a current density of 1 C (544 mA g-1). Even upon cycling at a current density of 4 C, the as-prepared Co9S8/N-C can still deliver a discharge capacity of 518 mAh g-1. The excellent battery performance can be attributed to the hollow structure as well as the N-rich carbon encapsulation. Moreover, this metal-organic framework sulfurization route also shows good generality for the synthesis of other metal sulfide-carbon composites such as ZnS/N-C and Cu2S/C.
authors.affiliation: Key Laboratory of Functional Molecular Solids, Ministry of Education, Center for Nano Science and Technology, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, East Beijing Road 1#, 241000, P.R. China.
authors.forename: Peiyuan
authors.initials: P
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Functional Molecular Solids, Ministry of Education, Center for Nano Science and Technology, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, East Beijing Road 1#, 241000, P.R. China.
authors.forename: Jianwen
authors.initials: J
authors.lastname: Li
authors.affiliation: Key Laboratory of Functional Molecular Solids, Ministry of Education, Center for Nano Science and Technology, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, East Beijing Road 1#, 241000, P.R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Ye
authors.affiliation: Key Laboratory of Functional Molecular Solids, Ministry of Education, Center for Nano Science and Technology, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, East Beijing Road 1#, 241000, P.R. China.
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Zhuo
authors.affiliation: Key Laboratory of Functional Molecular Solids, Ministry of Education, Center for Nano Science and Technology, College of Chemistry and Materials Science, Anhui Normal University, Wuhu, East Beijing Road 1#, 241000, P.R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Fang
keywords: Co9S8; electrochemistry; lithium-ion batteries; metal-organic frameworks; nanoparticles