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Abstract The development of practical lithium–sulfur (Li–S) batteries with prolonged cycle life and high Coulombic efficiency is limited by both parasitic reactions from dissolved polysulfides and mossy lithium deposition. To address these challenges, here lithium trithiocarbonate (Li2CS3)-coated lithium sulfide (Li2S) is employed as a dual-function cathode material to improve the cycling performance of Li–S batteries. Interestingly, at the cathode, Li2CS3 forms an oligomer-structured layer on the surface to suppress polysulfide shuttle. The presence of Li2CS3 alters the conventional sulfur reaction pathway, which is supported by material characterization and density functional theory calculation. At the anode, a stable in situ solid electrolyte interphase layer with a lower Li-ion diffusion barrier is formed on the Li-metal surface to engender enhanced lithium plating/stripping performance upon cycling. Consequently, the obtained anode-free full cells with Li2CS3 exhibit a superior capacity retention of 51% over 125 cycles, whereas conventional Li2S cells retain only 26%. This study demonstrates that Li2CS3 inclusion is an efficient strategy for designing high-energy-density Li–S batteries with extended cycle life.
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Anode-Free Lithium–Sulfur Batteries with a Rare-Earth Triflate as a Dual-Function Electrolyte Additive
Anode-free lithium-sulfur batteries feature a cell design with a fully-lithiated cathode and a bare current collector as an anode to control the total amount of lithium in the cell. The lithium stripping and deposition is a key factor in designing an anode-free full cell to realize a practical cell configuration. To realize effective anode protection and achieve a good performance of the anode-free full cell, the manipulation of the electrolyte chemistry toward the modification of the solid-electrolyte interphase on the anode is considered a feasible approach. In this study, the use of neodymium triflate, Nd(OTf)3, as a dual-function electrolyte additive is demonstrated to promote homogeneous catalysis on the cathode conversion reactions and the anode stabilization. Nd(OTf)3 not only facilitates the conversion reaction by promoting the polysulfide adsorption, but also effectively protects the lithium-metal anode and stabilizes the lithium stripping and deposition during cycling. With this electrolyte modification, both Li ǁ Li2S half cells and Ni ǁ Li2S anode-free full cells support a high areal capacity of 5.5 – 7.0 mA h cm-2 and maintain a high Coulombic efficiency of 94 – 95% during cycling.
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- Award ID(s):
- 2011415
- PAR ID:
- 10532493
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- ACS Applied Materials & Interfaces
- Volume:
- 16
- Issue:
- 27
- ISSN:
- 1944-8244
- Page Range / eLocation ID:
- 34997 to 35005
- Subject(s) / Keyword(s):
- lithium-sulfur batteries electrolyte metal triflate homogeneous catalysis polysulfide
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1021/acsami.4c05414
