Key Takeaways & Executive Findings
- •• FCNS@NCFs, a nitrogen-doped carbon fiber loaded with ternary metal sulfide (Fe, Co, Ni)9S8, serves as an effective sulfur host for Li-S batteries. • The material exhibits high catalytic activity and selective polysulfide adsorption, enhancing sulfur conversion kinetics and suppressing the shuttle effect. • At room temperature, the FCNS@NCFs-based cathode delivers an initial discharge capacity of 1639.0 mAh g−1 at 0.2 C and retains 1255.1 mAh g−1 after 100 cycles. • At −20 °C, the cathode still achieves an initial capacity of 1578.5 mAh g−1 and retains 867.5 mAh g−1 after 100 cycles, demonstrating excellent low-temperature performance.
Abstract
The use of lithium-sulfur (Li-S) batteries is limited by sulfur redox reactions involving multi-phase transformations, especially at low temperatures. To address this issue, we report a material (FCNS@NCFs) consisting of nitrogen-doped carbon fibers loaded with a ternary metal sulfide ((Fe, Co, Ni)9S8) for use as the sulfur host in Li-S batteries. This material was prepared using transfer blot filter paper as the carbon precursor, thiourea as the source of nitrogen and sulfur, and FeCl3·6H2O, CoCl2·6H2O and NiCl2·6H2O as the metal ion sources. It was synthesized by an impregnation method followed by calcination. The nitrogen doping significantly increased the conductivity of the host, and the metal sulfides have excellent catalytic activities. Theoretical calculations, and adsorption and deposition experiments show that active sites on the surface of FCNS@NCFs selectively adsorb polysulfides, facilitate rapid adsorption and conversion, prevent cathode passivation and inhibit the polysulfide shuttling. The FCNS@NCFs used as the sulfur host has excellent electrochemical properties. Its initial discharge capacity is 1639.0 mAh g−1 at 0.2 C and room temperature, and it remains a capacity of 1255.1 mAh g−1 after 100 cycles. At −20 °C, it has an initial discharge capacity of 1578.5 mAh g−1 at 0.2 C, with a capacity of 867.5 mAh g−1 after 100 cycles. Its excellent performance at both ambient and low temperatures suggests a new way to produce high-performance low-temperature Li-S batteries.
1. Introduction
The growing requirement for energy has increased the reliance on rechargeable lithium-ion batteries. Currently, the capacities of cathode and anode materials by intercalation/de-intercalation mechanisms have reached their theoretical maxima, prompting the requirement for novel electrochemical energy storage solutions[1–2]. Lithium-sulfur (Li-S) batteries are emerging as the most promising alternative for next-generation electrochemical energy storage. In comparison to lithium-ion batteries which use materials, such as LiCoO2, LiFePO4 and LiMn2O4 for cathodes, Li-S batteries show superior theoretical specific capacity and energy density, along with plentiful raw material availability, environmental benefits and cost-effectiveness. However, their development is limited by the slow kinetics of the liquid-solid phase reaction and the shuttle effect, complicating practical applications[3–6].
Research has identified 3 main strategies to mitigate these issues: the first leverages physical adsorption of lithium polysulfides (LiPSs) through carbon-based materials, such as graphene, porous carbons and carbon nanotubes[7–9]; the second employs chemical adsorption via inorganic and organic metal compounds, such as metal oxides, metal sulfides, metal nitrides and metal-organic frameworks[10–13]; the third involves the development of catalysts to improve sulfur reduction kinetics[14–16].
The catalyst for polysulfide transformation should have robust polysulfide adsorption capabilities, high electrical conductivity and substantial active sites[17–18]. However, the complex solvation/desolvation dynamics of LiPSs on the surface of the catalyst are often neglected. Polysulfides, enveloped by solvent molecules, form the solvation structure[19]. When polysulfides are adsorbed and converted on the catalyst surface, it is essential to surmount the interactions between the polysulfides and the constituents within the solvation structure, namely the desolvation process, which constitutes the primary component of the energy barrier for the sulfur redox reaction[20–22]. Notably, t
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HE Xin, ZUO Huai-yang, XIAO Ru, QU Zhuo-yan, SUN Zhen-hua, WANG Bao, Li Feng (2025). The use of a ternary metal sulfide loading on carbon fibers as the sulfur host for high performance low-temperature lithium sulfur batteries. SinoTechIntel Verified Research. https://doi.org/10.1016/S1872-5805(NCM2025-40-01-07)
Research & Educational Purpose Only:The translations, structured abstracts, analytical annotations, and data reports provided by SinoTechIntel are intended exclusively for academic research, internal corporate R&D, and educational benchmarking. They do not constitute formal engineering, chemical safety, legal, or professional advice.
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Frequently Asked Questions
What is the main challenge in lithium-sulfur batteries at low temperatures?
The main challenge is the slow kinetics of sulfur redox reactions involving multi-phase transformations, which are further exacerbated at low temperatures, leading to poor performance.
What material is proposed in this study to improve low-temperature Li-S battery performance?
The study proposes a material (FCNS@NCFs) consisting of nitrogen-doped carbon fibers loaded with a ternary metal sulfide ((Fe, Co, Ni)9S8) as the sulfur host.
How does the FCNS@NCFs material enhance battery performance?
The nitrogen doping increases conductivity, and the metal sulfides provide catalytic active sites that selectively adsorb polysulfides, facilitate rapid conversion, prevent cathode passivation, and inhibit the shuttle effect.
What are the specific capacity values achieved with FCNS@NCFs?
At room temperature, the initial discharge capacity is 1639.0 mAh g−1 at 0.2 C, retaining 1255.1 mAh g−1 after 100 cycles. At −20 °C, it achieves 1578.5 mAh g−1 initially and retains 867.5 mAh g−1 after 100 cycles.
What is the significance of this study for future battery technology?
This study demonstrates a new approach to designing sulfur hosts with high catalytic activity and low-temperature performance, paving the way for high-performance Li-S batteries suitable for cold environments.
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