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Improving Lithium‐Ion Diffusion Kinetics in Nano‐Si@C Anode Materials with Hierarchical MoS 2 Decoration for High‐Performance Lithium‐Ion Batteries
Author(s) -
Ye Xiongbiao,
Gan Chuanhai,
Huang Liuqing,
Qiu Yiwei,
Xu Ying,
Huang Liuying,
Luo Xuetao
Publication year - 2021
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202001626
Subject(s) - anode , materials science , lithium (medication) , silicon , diffusion , molybdenum disulfide , chemical engineering , carbon fibers , kinetics , nanotechnology , composite material , electrode , chemistry , metallurgy , thermodynamics , medicine , physics , quantum mechanics , composite number , engineering , endocrinology
A carbon layer on a silicon anode not only acts as a structural buffer to alleviate the tremendous volume expansion of silicon, but also enhances electrical conductivity. However, the carbon layer cannot improve the diffusion kinetics of Li + . Molybdenum disulfide (MoS 2 ) nanosheets are introduced on the outermost layer of yolk‐shell silicon@carbon to design urchin‐like hierarchical anode materials, which is of great benefit in structural stability. By contrast with the yolk‐shell silicon@carbon structure, the diffusion coefficient of Li + is improved, with 3.27 times greater performance during the delithiation processes and 2.04 times greater during the lithiation process with urchin‐like hierarchical structure, showing robust diffusion kinetics. Moreover, the MoS 2 nanosheets are able to enhance the delithiation reversibility of Li 15 Si 4 alloy formed during lithiation process. Because the MoS 2 nanosheets promote the structural stability, delithiation reversibility, and diffusion kinetics of Li + during lithiation/delithiation processes, the prepared hierarchical Si@C@MoS 2 composites exhibit a high reversible specific capacity of 1025 mAh g −1 with a capacity retention of approximately 81 % after 400 cycles at a current density of 1000 mAh g −1 , and the reversible specific capacity can reach 819 mAh g −1 even under a high rate of 5000 mA g −1 .