In:
Advanced Materials, Wiley, Vol. 35, No. 10 ( 2023-03)
Abstract:
High‐energy and long cycle lithium–sulfur (Li–S) pouch cells are limited by the insufficient capacities and stabilities of their cathodes under practical electrolyte/sulfur (E/S), electrolyte/capacity (E/C), and negative/positive (N/P) ratios. Herein, an advanced cathode comprising highly active Fe single‐atom catalysts (SACs) is reported to form 320.2 W h kg −1 multistacked Li–S pouch cells with total capacity of ≈1 A h level, satisfying low E/S (3.0), E/C (2.8), and N/P (2.3) ratios and high sulfur loadings (8.4 mg cm −2 ). The high‐activity Fe SAC is designed by manipulating its local environments using electron‐exchangeable binding (EEB) sites. Introducing EEB sites comprising two different types of S species, namely, thiophene‐like‐S (–S) and oxidized‐S (–SO 2 ), adjacent to Fe SACs promotes the kinetics of the Li 2 S redox reaction by providing additional binding sites and modulating the Fe d‐orbital levels via electron exchange with Fe. The –S donates the electrons to the Fe SACs, whereas –SO 2 withdraws electrons from the Fe SACs. Thus, the Fe d‐orbital energy level can be modulated by the different –SO 2 /–S ratios of the EEB site, controlling the electron donating/withdrawing characteristics. This desirable electrocatalysis is maximized by the intimate contact of the Fe SACs with the S species, which are confined together in porous carbon.
Type of Medium:
Online Resource
ISSN:
0935-9648
,
1521-4095
DOI:
10.1002/adma.202208999
Language:
English
Publisher:
Wiley
Publication Date:
2023
detail.hit.zdb_id:
1474949-X
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