Li-S batteries have been extensively studied using rigid carbon as the host for sulfur encapsulation, but improving the properties with a reduced electrolyte amount remains a significant challenge. This is critical for achieving high energy density. Here, we developed a soft PEOLiTFSI polymer swellable gel as a nanoscale reservoir to trap the polysulfides under lean electrolyte conditions. The PEOLiTFSI gel immobilizes the electrolyte and confines polysulfides within the ion conducting phase. The Li-S cell with a much lower electrolyte to sulfur ratio (E/S) of 4 g/g (3.3 mL/g) could deliver a capacity of 1200 mA h/g, 4.6 mA h/cm, and good cycle life. The accumulation of polysulfide reduction products, such as LiS, on the cathode, is identified as the potential mechanism for capacity fading under lean electrolyte conditions.
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http://dx.doi.org/10.1021/acs.nanolett.7b00417 | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Key Laboratory of Carbon Materials of Zhejiang Province, Wenzhou University, Wenzhou 325035, China.
Developing high-energy-density lithium-sulfur batteries faces serious polysulfide shuttle effects and sluggish conversion kinetics, often necessitating the excessive use of electrolytes, which in turn adversely affects battery performance. Our study introduces a meticulously designed electrocatalyst, Cu-CeO@N/C, to enhance lean-electrolyte lithium-sulfur battery performance. This catalyst, featuring in situ synthesized Cu clusters, regulates oxygen vacancies in CeO and forms Cu-CeO heterojunctions, thereby diminishing sulfur conversion barriers and hastening reaction kinetics through the generation of S/S intermediates.
View Article and Find Full Text PDFMembranes (Basel)
December 2024
PSI Center for Energy and Environmental Sciences, 5232 Villigen PSI, Switzerland.
The impeding ban on per- and polyfluoroalkyl substances (PFAS) prompted researchers to focus on hydrocarbon-based materials as constituents of next-generation proton exchange membranes (PEMs) for polymer electrolyte fuel cells (PEFCs). Here, we report on the fuel cell performance and durability of fluorine-lean PEMs prepared by the post-sulfonation of co-grafted α-methylstyrene (AMS) and 2-methylene glutaronitrile (MGN) monomers into preirradiated 12 µm polyvinylidene fluoride (PVDF) base film. The membranes were subjected to two distinctly different accelerated stress test (AST) protocols performed at open-circuit voltage (OCV): the US Department of Energy-similar chemical AST (90 °C, 30% relative humidity (RH), H/air, 1 bar), developed originally for perfluoroalkylsulfonic acid (PFSA) membranes, and the high relative humidity AST (80 °C, 100% RH, H/O, 2.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Department of Chemistry and Shanghai Key Laboratory of Molecular, Catalysis and Innovative Materials, iChEM (Collaborative Innovation Center of Chemistry for Energy Materials), Fudan University, Shanghai, 200433, China.
Sn redox chemistry in aqueous acidic electrolyte was characterized with high reversibility and kinetics, which is considered as competitive anode material for aqueous batteries. Unfortunately, divalent Sn is unstable in aqueous electrolyte. It was revealed that Sn is easy to be oxidized to tetravalent Sn by dissolved oxygen and then forms precipitate through hydrolysis process, leading to serious performance decay.
View Article and Find Full Text PDFSmall
December 2024
School of Materials science and Engineering, Zhengzhou University, Zhengzhou, 450001, China.
The mesopores and macropores within porous carbon materials help increase the surface for the depostion of solid-state products, reduce the LiS film thickness, enhance electron and mass transport, and accelerate the reaction kinetics. However, an excessive amount of mesopores and macropores can lead to increased electrolyte consumption, particularly at high sulfur loadings, where excessive electrolyte usage hampers the enhancement of practical energy density in lithium-sulfur (Li-S) batteries. A rational pore structure can minimize the amount of electrolyte to fill the pores, thereby reducing electrolyte consumption while achieving rapid reaction kinetics and a high gravimetric energy density.
View Article and Find Full Text PDFACS Nano
December 2024
Shenzhen Geim Graphene Center, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Carbon nanotubes (CNTs) with exceptional conductivity have been widely adopted in lithium-sulfur (Li-S) batteries. While trace metal impurities in CNTs have demonstrated electrocatalytic activity in various catalytic processes, their influence on sulfur electrocatalysis in Li-S batteries has been largely overlooked. Herein, we reveal that the trace metal impurities content in CNTs significantly improves the specific capacity and cycling performance of Li-S batteries by analyzing both our own results and previous literature with CNTs as the sulfur hosts.
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