Open AccessCofactor‐Assisted Artificial Enzyme with Multiple Li‐Bond Networks for Sustainable Polysulfide Conversion in Lithium–Sulfur Batteries
Author(s) -
Zhou Suya,
Yang Shuo,
Cai Dong,
Liang Ce,
Yu Shuang,
Hu Yue,
Nie Huagui,
Yang Zhi
Publication year - 2022
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202104205
Subject(s) - polysulfide , hemin , catalysis , sulfur , chemistry , covalent bond , cathode , lithium–sulfur battery , electrolyte , materials science , chemical engineering , inorganic chemistry , organic chemistry , electrode , heme , enzyme , engineering
Lithium–sulfur batteries possess high theoretical energy density but suffer from rapid capacity fade due to the shuttling and sluggish conversion of polysulfides. Aiming at these problems, a biomimetic design of cofactor‐assisted artificial enzyme catalyst, melamine (MM) crosslinked hemin on carboxylated carbon nanotubes (CNTs) (i.e., [CNTs–MM–hemin]), is presented to efficiently convert polysulfides. The MM cofactors bind with the hemin artificial enzymes and CNT conductive substrates through FeN 5 coordination and/or covalent amide bonds to provide high and durable catalytic activity for polysulfide conversions, while π – π conjugations between hemin and CNTs and multiple Li‐bond networks offered by MM endow the cathode with good electronic/Li + transmission ability. This synergistic mechanism enables rapid sulfur reaction kinetics, alleviated polysulfide shuttling, and an ultralow (<1.3%) loss of hemin active sites in electrolyte, which is ≈60 times lower than those of noncovalent crosslinked samples. As a result, the Li–S battery using [CNTs–MM–hemin] cathode retains a capacity of 571 mAh g −1 after 900 cycles at 1C with an ultralow capacity decay rate of 0.046% per cycle. Even under raising sulfur loadings up to 7.5 mg cm −2 , the cathode still can steadily run 110 cycles with a capacity retention of 83%.