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VN/S Nanoclusters Encapsulated with Graphene via Zeta Potential Control: A Pomegranate‐Like Cathode for Lithium‐Sulfur Batteries with Enhanced Rate Performance
Author(s) -
Qu Long,
Liu Pei,
Tian Xiaolu,
Shu Chengyong,
Yi Yikun,
Yang Pu,
Wang Te,
Fang Binren,
Li Mingtao,
Yang Bolun
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.202000163
Subject(s) - materials science , nanoclusters , graphene , cathode , electrochemistry , zeta potential , chemical engineering , catalysis , lithium (medication) , nanotechnology , raman spectroscopy , nanoparticle , electrode , chemistry , organic chemistry , medicine , physics , optics , endocrinology , engineering
A pomegranate‐like cathode, VN/S@G, is synthesized according to a simple principle of electrostatic attraction through a controllable Zeta potential method, establishing a hierarchical‐structured VN/S nanoclusters encapsuled with graphene nanosheets. Internal VN nanoparticles trap lithium polysulphides (LiPSs) and catalyse them transforming from long‐chain to short‐chain species; whereas the external cladding layers of graphene nanosheets confine the transformations in a nanoscale‐catalysis reactors. VN/S@G cathode exhibits excellent long‐cycling life at 2 C rate during the 2000 cycles, corresponding to 0.038 percent of capacity fade per cycle. According to in‐situ Raman and electrochemical impedance spectroscopies, VN catalyst accelerates chemical transformations of liquid‐state LiPSs to solid‐state Li 2 S 2 /Li 2 S and graphene intensifies Li + diffusion behaviour. Improvement of electrochemical performance of the VN/S@G cathode depends on a coefficient of physical and chemical interactions between VN catalyst and LiPSs species.