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In Situ Formation of Co 9 S 8 /N‐C Hollow Nanospheres by Pyrolysis and Sulfurization of ZIF‐67 for High‐Performance Lithium‐Ion Batteries
Author(s) -
Zeng Peiyuan,
Li Jianwen,
Ye Ming,
Zhuo Kaifeng,
Fang Zhen
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201700881
Subject(s) - polysulfide , materials science , anode , pyrolysis , chemical engineering , carbon fibers , nanoparticle , battery (electricity) , lithium ion battery , lithium (medication) , current density , electrode , nanotechnology , chemistry , composite material , electrolyte , medicine , power (physics) , physics , quantum mechanics , endocrinology , composite number , engineering
Co 9 S 8 is 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 Co 9 S 8 is 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, Co 9 S 8 embedded 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. Co 9 S 8 nanoparticles 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 −1 is 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 Co 9 S 8 /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 Cu 2 S/C.