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Quasi-Solid-State Electrolyte Induced by Metallic MoS2 for Lithium-Sulfur Batteries.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Yang, Ziwei Jeffrey  ORCID logo  https://orcid.org/0009-0002-0442-0080
Moloney, James 

Abstract

Lithium-sulfur (Li-S) batteries are a promising high-energy-density technology for next-generation energy storage but suffer from an inadequate lifespan. The poor cycle life of Li-S batteries stems from their commonly adopted catholyte-mediated operating mechanism, where the shuttling of dissolved polysulfides results in active material loss on the sulfur cathode and surface corrosion on the lithium anode. Here, we report in situ formation of a quasi-solid-state electrolyte (QSSE) on the metallic 1T phase molybdenum disulfide (MoS2) host that extends the lifetime of Li-S batteries. We find that the metallic 1T phase MoS2 host is able to initiate the ring-opening polymerization of 1,3-dioxolane (DOL), forming an integrated QSSE inside batteries. Nuclear magnetic resonance analysis reveals that the QSSE consists of ∼13% liquid DOL in a solid polymer matrix. The QSSE efficiently mediates sulfur redox reactions through dissolution-conversion chemistry while simultaneously suppressing polysulfide shuttling. Therefore, while ensuring high sulfur utilization, it avoids degradation of both electrodes, as well as the concomitant electrolyte consumption, leading to enhanced cycling stability. Under a practical lean electrolyte condition (electrolyte-to-sulfur ratio = 2 μL mg-1), Li-S pouch cell batteries with the QSSE demonstrate a capacity retention of 80.7% after 200 cycles, much superior to conventional liquid electrolyte cells that fail within 70 cycles. The QSSE also enables Li-S pouch cell batteries to operate across a wider temperature range (5 to 45 °C), together with improved safety under mechanical damage.

Description

Keywords

2D MoS2, Cycle life, Li−S battery, Metallic 1T phase, Quasi-solid-state electrolyte

Journal Title

ACS Nano

Conference Name

Journal ISSN

1936-0851
1936-086X

Volume Title

Publisher

American Chemical Society (ACS)
Sponsorship
Engineering and Physical Sciences Research Council (EP/L016087/1)
Engineering and Physical Sciences Research Council (EP/P024947/1)
EPSRC (EP/T001038/1)
Engineering and Physical Sciences Research Council (EP/R00661X/1)