Mo3P/Mo heterojunction for efficient conversion of lithium polysulfides in high-performance lithium-sulfur batteries
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PROVIDER: S-EPMC11345131 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:Despite having ultra-high theoretical specific capacity and theoretical energy density, lithium-sulfur (Li-S) batteries suffer from their low Coulombic efficiency and poor lifespan, and the commercial application of Li-S batteries is seriously hampered by the severe "shuttle effect" of lithium polysulfides (LiPSs) and the large volume expansion ratio of the sulfur electrode during cycling. Designing functional hosts for sulfur cathodes is one of the most effective ways to immobilize the LiPSs and improve the electrochemical performance of a Li-S battery. In this work, a polypyrrole (PPy)-coated anatase/bronze TiO2 (TAB) heterostructure was successfully prepared and used as a sulfur host. Results showed that the porous TAB could physically adsorb and chemically interact with LiPSs during charging and discharging processes, inhibiting the LiPSs' shuttle effect, and the TAB's heterostructure and PPy conductive layer are conducive to the rapid transport of Li+ and improve the conductivity of the electrode. By benefitting from these merits, Li-S batteries with TAB@S/PPy electrodes could deliver a high initial capacity of 1250.4 mAh g-1 at 0.1 C and show an excellent cycling stability (the average capacity decay rate was 0.042% per cycle after 1000 cycles at 1 C). This work brings a new idea for the design of functional sulfur cathodes for high-performance Li-S battery.
| S-EPMC10254138 | biostudies-literature
Project description: Not available
| S-EPMC11242168 | biostudies-literature
Project description:Lithium-sulfur batteries are anticipated to be the next generation of energy storage devices because of their high theoretical specific capacity. However, the polysulfide shuttle effect of lithium-sulfur batteries restricts their commercial application. The fundamental reason for this is the sluggish reaction kinetics between polysulfide and lithium sulfide, which causes soluble polysulfide to dissolve into the electrolyte, leading to a shuttle effect and a difficult conversion reaction. Catalytic conversion is considered to be a promising strategy to alleviate the shuttle effect. In this paper, a CoS2-CoSe2 heterostructure with high conductivity and catalytic performance was prepared by in situ sulfurization of CoSe2 nanoribbon. By optimizing the coordination environment and electronic structure of Co, a highly efficient CoS2-CoSe2 catalyst was obtained, to promote the conversion of lithium polysulfides to lithium sulfide. By using the modified separator with CoS2-CoSe2 and graphene, the battery exhibited excellent rate and cycle performance. The capacity remained at 721 mAh g-1 after 350 cycles, at a current density of 0.5 C. This work provides an effective strategy to enhance the catalytic performance of two-dimensional transition-metal selenides by heterostructure engineering.
| S-EPMC10254419 | biostudies-literature
Project description:MoS2 /C composites constructed with van der Waals forces have been extensively applied in lithium-sulfur (Li-S) batteries. However, the catalytic conversion effect on polysulfides is limited because the weak electronic interactions between the composite interfaces cannot fundamentally improve the intrinsic electronic conductivity of MoS2 . Herein, density functional theory calculations reveal that the MoS2 and nitrogen-doped carbon composite with an Mo-O-C bond can promote the catalytic conversion of polysulfides with a Gibbs free energy of only 0.19 eV and a low dissociation energy barrier of 0.48 eV, owing to the strong covalent coupling effect on the heterogeneous interface. Guided by theoretical calculations, a robust MoS2 strongly coupled with a 3D carbon matrix composed of nitrogen-doped reduced graphene oxide and carbonized melamine foam is designed and constructed as a multifunctional coating layer for lithium-sulfur batteries. As a result, excellent electrochemical performance is achieved for Li-S batteries, with a capacity of 615 mAh g-1 at 5 C, an areal capacity of 6.11 mAh cm-2 , and a low self-discharge of only 8.6% by resting for five days at 0.5 C. This study opens a new avenue for designing 2D material composites toward promoted catalytic conversion of polysulfides.
| S-EPMC9353409 | biostudies-literature
Project description:Lithium-sulfur batteries have attracted great attention because of their high energy density, environmental friendliness, natural abundance and intrinsically low cost of sulfur. However, their commercial applications are greatly hindered by rapid capacity decay due to poor conductivity of electrode, fast dissolution of the intermediate polysulfides into the electrolyte, and the volume expansion of sulfur. Herein, we report a novel composite MWCNTs@TiO2-S nanostructure by grafting TiO2 onto the surface of MWCNTs, followed by incorporating sulfur into the composite. The inner MWCNTs improved the mechanical strength and conductivity of the electrode and the outer TiO2 provided the adsorption sites to immobilize polysulfides due to bonding interaction between TiO2 and polysulfides. The MWCNTs@TiO2-S composite with a mass ratio of 50% (MWCNTs in MWCNTs@TiO2) exhibited the highest electrochemistry performance among all compositing ratios of MWCNTs/TiO2. The performance improvement might be attributed to the downward shift of the apparent Fermi level to a more positive potential and electron rich space region at the interface of MWCNTs-TiO2 that facilitates the reduction of lithium polysulfide at a higher potential. Such a novel hybrid structure can be applicable for electrode design in other energy storage applications.
| S-EPMC5241630 | biostudies-literature
Project description:Lithium-sulfur batteries have emerged as one of the promising next-generation energy storage devices. However, the dissolution and shuttling of polysulfides in the electrolyte leads to a rapid decrease in capacity, severe self-discharge, and poor high-temperature performance. Here, we demonstrate the design and preparation of a Mo2C nanoparticle-embedded carbon nanosheet matrix material (Mo2C/C) and its application in lithium-sulfur battery separator modification. As a polar catalyst, Mo2C/C can effectively adsorb and promote the reversible conversion of lithium polysulfides, suppress the shuttle effect, and improve the electrochemical performance of the battery. The lithium-sulfur battery with the Mo2C/C =-modified separator showed a good rate of performance with high specific capacities of 1470 and 799 mAh g-1 at 0.1 and 2 C, respectively. In addition, the long-cycle performance of only 0.09% decay per cycle for 400 cycles and the stable cycling under high sulfur loading indicate that the Mo2C/C-modified separator holds great promise for the development of high-energy-density lithium-sulfur batteries.
| S-EPMC9964068 | biostudies-literature
Project description:Within the lithium-sulfur (Li-S) battery, a wide variety of soluble lithium polysulfide intermediates form during operation. Under lean-electrolyte or low-temperature conditions, the solution coordination of polysulfides dynamically shifts to highly clustered states, which is subsequently accompanied by inhibited electrochemical kinetics. In fact, it has been shown that the tendency for polysulfides to strongly aggregate is one of the dominant kinetically limiting obstacles towards achieving adequate utilization of active material under such conditions. While this association has been noted before, it is not explicitly understood what mechanism intrinsic to polysulfide clustering curtails the electrochemical utilization of active material, particularly during the conversion to insoluble Li2S. Here, we perform a series of investigations to unify and link the kinetic constraints that arise from polysulfide clustering to the nucleation and growth behavior of Li2S. We find that there is a drastic decrease in polysulfide diffusion coefficient arising from the advent of clustering, and that this decline functionally matches that seen for the nucleation and growth rate constants for Li2S deposition. Additionally, it is found that there is a less favorable minimization of energy during Li2S nucleation, arising from the altered solvation stability of polysulfide clusters. This knowledge expands our understanding of the Li-S materials chemistry and the primary factors dictating the electrochemical behavior.
| S-EPMC8243368 | biostudies-literature
Project description:Potassium-sulfur batteries attract tremendous attention as high-energy and low-cost energy storage system, but achieving high utilization and long-term cycling of sulfur remains challenging. Here we show a strategy of optimizing potassium polysulfides for building high-performance potassium-sulfur batteries. We design the composite of tungsten single atom and tungsten carbide possessing potassium polysulfide migration/conversion bi-functionality by theoretical screening. We create two ligand environments for tungsten in the metal-organic framework, which respectively transmute into tungsten single atom and tungsten carbide nanocrystals during pyrolysis. Tungsten carbide provide catalytic sites for potassium polysulfides conversion, while tungsten single atoms facilitate sulfides migration thereby significantly alleviating the insulating sulfides accumulation and the associated catalytic poisoning. Resultantly, highly efficient potassium-sulfur electrochemistry is achieved under high-rate and long-cycling conditions. The batteries deliver 89.8% sulfur utilization (1504 mAh g-1), superior rate capability (1059 mAh g-1 at 1675 mA g-1) and long lifespan of 200 cycles at 25 °C. These advances enlighten direction for future KSBs development.
| S-EPMC10837207 | biostudies-literature
Project description:The incorporation of highly polarized inorganic compounds in functional separators is expected to alleviate the high temperature safety- and performance-related issues for promising lithium-sulfur batteries. In this work, a unique Co3O4 polyhedral coating on thermal-stable polyimide (PI) separators was developed by a simple one-step low-temperature calcination method utilizing metal-organic framework (MOF) of Co-based zeolitic-imidazolate frameworks (ZIF-Co) precursors. The unique Co3O4 polyhedral structures possess several structural merits including small primary particle size, large pore size, rich grain boundary, and high ionic conductivity, which endow the ability to adequately adsorb dissolved polysulfides. The flexible-rigid lithium-lanthanum-zirconium oxide-poly(ethylene oxide) (LLZO-PEO) coating has been designed on another side of the polyimide non-woven membranes to inhibit the growth of lithium dendrites. As a result, the as-fabricated Co3O4/polyimide/LLZO-PEO (Co3O4/PI/LLZO) composite separators displayed fair dimensional stability, good mechanical strength, flame retardant properties, and excellent ionic conductivity. More encouragingly, the separator coating of Co3O4 polyhedrons endows Li-S cells with unprecedented high temperature properties (tested at 80 °C), including rate performance 620 mAh g-1 at 4.0 C and cycling stability of 800 mAh g-1 after 200 cycles-much better than the state-of-the-art results. This work will encourage more research on the separator engineering for high temperature operation.
| S-EPMC6915487 | biostudies-literature
Project description:The sluggish kinetics of sulfur conversions have long been hindering the implementation of fast and efficient sulfur electrochemistry in lithium-sulfur (Li-S) batteries. In this regard, herein the unique chromium boride (CrB) is developed via a well-confined mild-temperature thermal reaction to serve as an advanced sulfur electrocatalyst. Its interstitial-alloy nature features excellent conductivity, while the nano-lamination architecture affords abundant active sites for host-guest interactions. More importantly, the CrB nanocatalyst demonstrates a dual sulphophilicity with simultaneous Cr─S and B─S bondage for establishing strong interactions with the intermediate polysulfides. As a result, significant stabilization and promotion of sulfur redox behavior can be achieved, enabling an excellent Li-S cell cyclability with a minimum capacity fading rate of 0.0176% per cycle over 2000 cycles and a favorable rate capability up to 7 C. Additionally, a high areal capacity of 5.2 mAh cm-2 , and decent cycling and rate performances are still attainable under high sulfur loading and low electrolyte dosage. This work offers a facile approach and instructive insights into metal boride sulfur electrocatalyst, holding a good promise for pursuing high-efficiency sulfur electrochemistry and high-performance Li-S batteries.
| S-EPMC10646252 | biostudies-literature