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Electrochemical Phase Evolution of Metal‐Based Pre‐Catalysts for High‐Rate Polysulfide Conversion
Author(s) -
Zhao Meng,
Peng HongJie,
Li BoQuan,
Chen Xiao,
Xie Jin,
Liu Xinyan,
Zhang Qiang,
Huang JiaQi
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202003136
Subject(s) - polysulfide , electrochemistry , materials science , phase (matter) , catalysis , metal , chemical engineering , metallurgy , chemistry , electrode , organic chemistry , engineering , electrolyte
In situ evolution of electrocatalysts is of paramount importance in defining catalytic reactions. Catalysts for aprotic electrochemistry such as lithium–sulfur (Li‐S) batteries are the cornerstone to enhance intrinsically sluggish reaction kinetics but the true active phases are often controversial. Herein, we reveal the electrochemical phase evolution of metal‐based pre‐catalysts (Co 4 N) in working Li‐S batteries that renders highly active electrocatalysts (CoS x ). Electrochemical cycling induces the transformation from single‐crystalline Co 4 N to polycrystalline CoS x that are rich in active sites. This transformation propels all‐phase polysulfide‐involving reactions. Consequently, Co 4 N enables stable operation of high‐rate (10 C, 16.7 mA cm −2 ) and electrolyte‐starved (4.7 μL mg S −1 ) Li‐S batteries. The general concept of electrochemically induced sulfurization is verified by thermodynamic energetics for most of low‐valence metal compounds.