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Nitrogen‐Doped Hollow Carbon Polyhedrons with Carbon Nanotubes Surface Layers as Effective Sulfur Hosts for High‐Rate, Long‐Lifespan Lithium–Sulfur Batteries
Author(s) -
Fan Bin,
Zhao Dengke,
Zhou Wei,
Xu Wei,
Liang Xinghua,
He Guoqiang,
Wu Zexing,
Li Ligui
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202001310
Subject(s) - sulfur , materials science , carbon fibers , cathode , lithium (medication) , nitrogen , chemical engineering , carbon nanotube , adsorption , conductivity , crystallite , composite material , chemistry , organic chemistry , metallurgy , composite number , engineering , endocrinology , medicine
Abstract Effectively confining lithium polysulfides inside porous material matrix with a high electrical conductivity represents a judicious way to extend lifespan and enhance rate performance of lithium‐sulfur (Li‐S) batteries. Herein, nitrogen‐doped hollow carbon polyhedrons with a thin CNTs conductive surface layer (CNTs/HNC) were prepared by directly pyrolyzing the CNTs coated ZIF‐8 polyhedrons crystallite precursors, and subsequently served as sulfur hosts in Li‐S batteries. The resulted product CNTs/HNC‐800 comprises a nitrogen content of 4.94 at.% as well as a high electrical conductivity of 8.43×10 −1 S cm −1 , which help to effectively adsorb/confine lithium polysulfides and substantially improve the rate capacity of Li‐S batteries. With a sulfur loading of 1.60 mg cm −2 , the S@CNTs/HNC based cathode shows a discharge capacity of 870.7 mAh g −1 at 1.0 C, and can maintain 76.4 % of its initial capacity after 500 charge‐discharge cycles, corresponding to a capacity fade rate of only 0.047 % per cycle. While with a higher sulfur loading of 2.46 mg cm −2 , a discharge capacity of 649.7 mAh g −1 can be achieved at 0.5 C, along with a capacity fade rate of merely 0.044 % per cycle during 200 cycles. When sulfur loading is further increased to 5.39 mg cm −2 , it can also maintain a considerable initial discharge capacity of 812 mAh g −1 at 0.1 C. This work enriches the ways to prepare complicate nano structured sulfur hosts for long‐life and high‐rate Li‐S batteries.