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Engineering Fe–N Coordination Structures for Fast Redox Conversion in Lithium–Sulfur Batteries
Author(s) -
Ma Cheng,
Zhang Youquan,
Feng Yiming,
Wang Ning,
Zhou Liangjun,
Liang Chaoping,
Chen Libao,
Lai Yanqing,
Ji Xiaobo,
Yan Chenglin,
Wei Weifeng
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202100171
Subject(s) - separator (oil production) , catalysis , electrochemistry , materials science , cathode , redox , selectivity , chemical engineering , sulfur , adsorption , graphene , lithium (medication) , inorganic chemistry , electrode , nanotechnology , chemistry , organic chemistry , metallurgy , physics , engineering , thermodynamics , medicine , endocrinology
Abstract Critical drawbacks, including sluggish redox kinetics and undesirable shuttling of polysulfides (Li 2 S n , n = 4–8), seriously deteriorate the electrochemical performance of high‐energy‐density lithium–sulfur (Li–S) batteries. Herein, these challenges are addressed by constructing an integrated catalyst with dual active sites, where single‐atom (SA)‐Fe and polar Fe 2 N are co‐embedded in nitrogen‐doped graphene (SA‐Fe/Fe 2 N@NG). The SA‐Fe, with plane‐symmetric Fe‐4N coordination, and Fe 2 N, with triangular pyramidal Fe‐3N coordination, in this well‐designed configuration exhibit synergistic adsorption of polysulfides and catalytic selectivity for Li 2 S n lithiation and Li 2 S delithiation, respectively. These characteristics endow the SA‐Fe/Fe 2 N@NG‐modified separator with an optimal polysulfides confinement–catalysis ability, thus accelerating the bidirectional liquid–solid conversion (Li 2 S n ↔Li 2 S) and suppressing the shuttle effect. Consequently, a Li–S battery based on the SA‐Fe/Fe 2 N@NG separator achieves a high capacity retention of 84.1% over 500 cycles at 1 C (pure S cathode, S content: 70 wt%) and a high areal capacity of 5.02 mAh cm −2 at 0.1 C (SA‐Fe/Fe 2 N@NG‐supported S cathode, S loading = 5 mg cm −2 ). It is expected that the outcomes of the present study will facilitate the design of high‐efficiency catalysts for long‐lasting Li–S batteries.