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A Self‐Standing and Flexible Electrode of Yolk–Shell CoS 2 Spheres Encapsulated with Nitrogen‐Doped Graphene for High‐Performance Lithium‐Ion Batteries
Author(s) -
Qiu Wenda,
Jiao Jiqing,
Xia Jian,
Zhong Haimin,
Chen Liuping
Publication year - 2015
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.201405821
Subject(s) - graphene , anode , materials science , electrode , lithium (medication) , coating , chemical engineering , nanotechnology , composite number , fabrication , composite material , chemistry , pathology , medicine , alternative medicine , endocrinology , engineering
Flexible lithium‐ion batteries (LIBs) have recently attracted increasing attention with the fast development of bendable electronic systems. Herein, a facile and template‐free solvothermal method is presented for the fabrication of hybrid yolk–shell CoS 2 and nitrogen‐doped graphene (NG) sheets. The yolk–shell architecture of CoS 2 encapsulated with NG coating is designed for the dual protection of CoS 2 to address the structural and interfacial stability concerns facing the CoS 2 anode. The as‐prepared composite can be assembled into a film, which can be used as a binder‐free and flexible electrode for LIBs that does not require any carbon black conducting additives or current collectors. When evaluating lithium‐storage properties, such a flexible electrode exhibits a high specific capacity of 992 mAh g −1 in the first reversible discharge capacity at a current rate of 100 mA g −1 and high reversible capacity of 882 mAh g −1 after 150 cycles with excellent capacity retention of 89.91 %. Furthermore, a reversible capacity as high as 655 mAh g −1 is still achieved after 50 cycles even at a high rate of 5 C due to the yolk–shell structure and NG coating, which not only provide short Li‐ion and electron pathways, but also accommodate large volume variation.