Lithium Sulfur Research Articles

Tailoring eco-friendly siloxane-based electrolytes for high-performance lithium–sulfur batteries

Lithium–sulfur batteries (LSBs), with their ultra-high theoretical energy density (2600 Wh kg−1), are considered one of the most attractive high-energy batteries. However, the “shuttling effect” of polysulfides and the uncontrolled growth of lithium (Li) dendrites pose significant challenges to the practical implementation of LSBs. Herein, a lightweight and eco-friendly diethoxydimethylsilane (DEMS) is chosen as a multi-functional solvent for LSBs. The low polarity of DEMS promotes the “solid–solid” conversion of sulfurized polyacrylonitrile (SPAN) during charge–discharge processes, eliminating the shuttle effect of polysulfides. Moreover, the DEMS-based electrolyte enables highly reversible Li plating/stripping processes across a wide temperature range spanning from −20 to 60 °C. As a result, the Li/SPAN batteries using the DEMS electrolyte exhibit excellent cyclic stability at 0.2 C with retainable capacities of 524.4 mAh/g after 200 cycles, 598.8 mAh/g after 100 cycles, and 318.6 mAh/g after 50 cycles at 26, 60 and −20 °C, respectively. This study aims to identify low-cost and highly stable electrolytes through solvent screening to enhance the electrochemical performance of LSBs.

Microreactor Strategy to Capture Sulfur for Lithium–Sulfur Batteries

Microreactor Strategy to Capture Sulfur for Lithium–Sulfur Batteries

Ionic Liquid-Assisted Synthesis of Higher Loaded Ni/Fe Dual-Atom Catalysts in N, F, B Codoped Carbon Matrix for Accelerated Sulfur Reduction Reaction.

In response to mitigating the severe shuttle effect within lithium-sulfur batteries, single-atom catalysts have emerged as one of the most effective solutions. Here, N, F, B codoped porous hollow carbon nanocages (NFB-NiFe@NC) with high Ni and Fe doping are rationally designed and synthesized using ionic liquids (ILs) as dopants. The introduction of ILs inhibits the growth of zeolitic imidazolate framework-8 (ZIF8), resulting in NFB-ZIF8 precursors with smaller particle sizes, enabling higher loading dual-atom catalysts. Meanwhile, the abundant heteroatoms increase the reactive sites and alter the carbon matrix's nonpolar intrinsic properties, thus enhancing the chemisorption of polysulfides. The synergistic interaction of the heteroatoms with Ni and Fe dual-atoms ultimately promotes the catalytic conversion kinetics of polysulfides. As a result of these beneficial properties, the cells prepared using the NFB-NiFe@NC modified separator exhibit significantly improved performance, including a high initial capacity of 1448 mAh g-1 at 0.2 C. Even at a high S-loading of 7.6 mg cm-2, the ideal area capacity of 8.38 mAh cm-2 can still be maintained at 0.1 C. New insights are provided here for designing highly loaded dual-atom catalysts for application in lithium-sulfur batteries.

Application of Y-MOF-CNT-Derived Y2O3-C@CNT Composites in Lithium-Sulfur Battery Separators.

In order to mitigate the shuttle effect of lithium polysulfides in lithium-sulfur batteries, we propose a yttrium-metal-organic framework-carbon nanotube (Y-MOF-CNT)-derived Y2O3-C@CNT composite for modifying the separator in this study. The Y-MOFs, comprising yttrium (Y) rare earth metal and terephthalic acid, exemplify a prototypical category of metal-organic framework (MOF) materials. They manifest the advantageous attributes associated with MOFs while concurrently possessing distinctive catalytic traits ascribed to rare earth elements. In this study, Y-MOF nanoparticles were synthesized on carbon nanotube (CNT) substrates via a facile aqueous solution method, succeeded by high-temperature carbonization to yield Y2O3-C@CNT composite materials. These composites were subsequently employed as coatings on one side of polyethylene (PE) separators. The resultant Y2O3-C@CNT composite inherits the particle-like morphology and porosity from its precursor Y-MOF, alongside the inherent conductivity in carbon-based materials. This amalgamation is conducive to polysulfide capture and catalytic conversion processes within lithium-sulfur batteries. The application of the Y2O3-C@CNT-coated PE separator effectively mitigated polysulfide shuttle effects and significantly enhanced the battery electrochemical performance. At a sulfur loading level of 3 mg cm-2 under a 0.5 C rate, an initial discharge specific capacity of 900 mAh g-1 was achieved. After 400 cycles, the discharge specific capacity remained at 483.85 mAh g-1 with a capacity retention rate of 53.7%. Upon increasing sulfur loading to 5 mg cm-2, the discharge specific capacity at a lower rate (0.1 C) reached 817.8 mAh g-1; even after 100 cycles, it maintained a value of 700 mAh g-1 with a capacity retention rate of 85.6%. Notably, our modified Y2O3-C@CNT separator demonstrated exceptional cycling stability, even under conditions involving high sulfur loading.

Modulation of d-Orbital Interactions in Dual-Atom Catalysts for Enhanced Polysulfide Anchoring and Kinetics in Lithium-Sulfur Batteries.

Modulating the electronic structure is essential for improving the anchoring and catalytic capabilities of catalysts in lithium-sulfur batteries (LSBs). This study delves into the modulation of d-orbitals in transition metal dual-atom catalysts (DACs) supported by boron nitride and graphene (BNC) hybrid sheets for LSBs. This study reveals that the d-band center of the DACs, a key determinant of material chemical properties, is primarily determined by the electronic configuration of the dyz and dx2-y2 orbitals. Furthermore, the interaction between dz2 of transition metals and S_3 p orbitals is critical for the binding strength of LiPSs. By understanding these interactions, the functionality of DACs can be customized for optimal performance in LSBs. For example, the MnCrBNC catalyst with 10 d-electrons exhibits the optimal d-band center and demonstrates exceptional LiPSs binding capability, the lowest Li2S decomposition energy barrier, and the lowest Gibbs free energy of reaction for the rate-determining step of sulfur reduction. This study elucidates the fundamental mechanisms for designing high-performance LSB catalysts through electronic structure modulation.

Highly interweaved carbonaceous interlayer synchronously decorated by foreign atoms and metals for adsorbing and catalyzing polysulfides in lithium-sulfur batteries

A highly interweaved carbonized bacterial cellulose (CBC) decorated by heteroatoms and metallic nanoparticles was fabricated through initial coating of a metallic coordination polymer onto BC nanofibers followed by carbonization. The carbonaceous CBC networks not only efficiently transfer electrons but also entrap the soluble polysulfides by physical interception. Moreover, the polar ingredients of foreign atoms and metals on CBC networks enable a favorable chemisorption toward polysulfides, and meanwhile the embedded metallic nanoparticles promote the conversion kinetics via electrocatalysis. Theoretical simulation and experimental investigation co-confirm that the decorated Ni species greatly enhance the adsorption capability towards polysulfides, as well as reduce the energy barrier of the rate-determining step via electrocatalysis. As a consequence, the lithium-sulfur batteries equipped with the optimal Ni-NCBC interlayer exhibited relatively high specific capacity (1245 mAh g−1 at 0.2 A g−1), superior rate capability (820 mAh g−1 at 4.0 A g−1), and stable cycling performance (73.2 % capacity retention after 1000 cycles). This work proposes a facile strategy to synchronously incorporate heteroatoms and metallic decorations into highly conductive nanofibrous networks for alleviating the shuttling effects of polysulfides effectively.

High-Energy-Density Lithium–Sulfur Battery Based on a Lithium Polysulfide Catholyte and Carbon Nanofiber Cathode

Li–S batteries are promising large-scale energy storage systems but currently suffer from performance issues; a major reason is the dissolution of polysulfides in electrolytes. To this end, we report a high-energy-density Lithium–Sulfur (Li–S) battery that combines a catholyte and a sulfur-free carbon nanofiber (CNF) cathode. The cathode was synthesized by carbonizing binder-free polyacrylonitrile (PAN) nanofibers, affording a high surface area. In the catholyte, added polysulfides acted as both conductive Li salts and active materials. Investigating the electrochemical performance of this concept in both Swagelok- and pouch-type cells afforded energy densities exceeding 3 mAh cm−2 at a discharge rate of 0.1 C. This combination could also be utilized in high-capacity pouch cells with capacities of up to 250 mAh g−1. Both cell types exhibited good cycle performance. Adding LiNO3 to the electrolyte suppressed the redox shuttle reactions. Moreover, the cathode being binder-free increased the energy density and simplified cathode fabrication. Characterizing the cathode before and after cycling revealed that deposition was reversible, and that cell reactions at least partially formed sulfur as the end product, resulting in high sulfur amounts in the cell. We expect our concept to greatly aid in the development of practically applicable Li–S cells.

ZIF‐67/ZIF‐8 and its Derivatives for Lithium Sulfur Batteries

AbstractLithium–sulfur batteries (LSBs), renowned for their superior energy density and the plentiful availability of sulfur resources, are progressively emerging as the focal point of forthcoming energy storage technology. Nevertheless, they presently confront fundamental challenges including insulation of sulfur and its discharge product, the lithium polysulfides (LiPSs) shuttle phenomenon, and the growth of lithium dendrites. Zeolite imidazole framework materials (ZIFs), particularly ZIF‐8 and ZIF‐67, are significant members of the metal–organic frameworks (MOFs) family. Owing to their high porosity, exceptional adsorption capacity, high structural tunability, and straightforward synthesis process, these materials have demonstrated unique application potential in the field of LSBs. This review initially provides a comprehensive summary of the developmental status and challenges associated with LSBs. Subsequently, it delves into an in‐depth analysis of the distinctive properties and synthesis strategies of ZIFs, with a particular emphasis on ZIF‐8 and ZIF‐67, as well as their composites and derivatives. The review systematically categorizes innovative application examples of these materials in the design of cathode structures and optimization of separators in LSBs. It also presents a forward‐looking perspective and insights on the potential future trajectory of ZIF‐67 materials, informed by the latest research advancements in the field.

Graphene-like porous carbon sheet/carbon nanotube composite as sulfur host for lithium-sulfur batteries

Graphene-like porous carbon sheet/carbon nanotube composite as sulfur host for lithium-sulfur batteries

Nitrogen-Doped Graphene Uniformly Loaded with Large Interlayer Spacing MoS2 Nanoflowers for Enhanced Lithium-Sulfur Battery Performance.

Lithium-sulfur (Li-S) batteries offer a high theoretical energy density but suffer from poor cycling stability and polysulfide shuttling, which limits their practical application. To address these challenges, we developed a PANI-modified MoS2-NG composite, where MoS2 nanoflowers were uniformly grown on graphene oxide (GO) through PANI modification, resulting in an increased interlayer spacing of MoS2. This expanded spacing exposed more active sites, enhancing polysulfide adsorption and catalytic conversion. The composite was used to prepare MoS2-NG/PP separators for Li-S batteries, which achieved a high specific capacity of 714 mAh g-1 at a 3 C rate and maintained a low capacity decay rate of 0.085% per cycle after 500 cycles at 0.5 C. The larger MoS2 interlayer spacing was key to improving redox reaction kinetics and suppressing the shuttle effect, making the MoS2-NG composite a promising material for enhancing the performance and stability of Li-S batteries.

A Multifunctional Additive for Long‐Cycling Lithium‐Sulfur Batteries Under Lean‐Ether‐Electrolyte Conditions

AbstractThe failure of lithium‐sulfur (Li‐S) batteries operating under lean‐ether‐electrolyte conditions can be ascribed to the deterioration of electrolytes, the passivation of cathodes, and the degeneration of lithium anodes. Efforts to address these challenges by exploring alternative electrolytes beyond commonly used ether‐based systems often introduce new complications. In this study, the utilization of a multifunctional additive, 2‐Bromoacetamide (BA), for ether electrolytes is proposed to achieve stable Li‐S batteries under lean‐electrolyte conditions. These investigations reveal that the amide bond in BA forms hydrogen bonds with sulfur atoms, promoting the dissolution of lithium sulfides (Li2S) in ether electrolytes and mediating the conversion of lithium polysulfides. This enhanced solubility of Li2S facilitates 3D deposition (vertical to the substrate) rather than the typical 2D deposition (parallel to the substrate) of Li2S, and thus alleviates the passivation of cathodes. Furthermore, the incorporation of BA promotes uniform and dense lithium deposition. The use of the BA‐containing electrolyte enables stable cycling of a Li‐S pouch cell for 40 cycles, even under a low electrolyte‐to‐sulfur ratio of 4 µL mg−1. This multifunctional strategy offers an effective solution to extend the lifetime of Li‐S batteries under lean‐electrolyte conditions, thereby paving the way for practical applications of Li‐S battery technology.

Nanosized CeO2C2 with rich oxygen vacancies embedded in hollow mesoporous carbon as a multifunctional sulfur-loaded matrix for lithium-sulfur batteries

The innovative structural and compositional design of sulfur-loaded matrices is an effective strategy to improve the performance of lithium-sulfur batteries (LSBs). Herein, nanosized CeO2C2 with rich oxygen vacancies embedded in hollow mesoporous carbon composites (HMC/CeO2C2) were synthesized by hydrothermal and annealing reduction processes. This structure has several advantages: the large specific surface area and mesoporous carbon walls facilitate sulfur penetration and electron/ion transport; the abundant mesopores and hollow inner cavities provide the structural basis for sulfur storage and buffer its volume expansion; the oxygen vacancy-rich CeO2C2 nanoparticles grown in situ in HMC and in close contact with carbon form an electrically favorable CeO2C2/C heterointerface as an efficient catalyst, which is conducive to catalyzing the redox reaction of sulfur. Consequently, the retention capacity of the HMC/CeO2C2/S electrode is 728 mAh g−1 after 500 cycles at 0.5 C with a decay rate of 0.056 % per cycle, and it maintains a high reversible area capacity of 3.18 mAh cm−2 and excellent cycling performance even under a high sulfur loading of 4.7 mg cm−2. It provides an idea for the development of multifunctional sulfur-loaded materials with high sulfur loading, high conductivity, and high catalytic activity.

Lyten plans lithium-sulfur battery plant

Lyten plans lithium-sulfur battery plant

Accelerating polysulfide conversion by employing C/MoS2 composite host for lithium-sulfur batteries

Accelerating polysulfide conversion by employing C/MoS2 composite host for lithium-sulfur batteries

Ultrafine Mo2N Quantum Dots Embedded in N-Doped Graphene Sheets Enable Efficient Adsorption-Catalytic Transformation of Polysulfides.

Because of the high theoretical energy density of 2600 Wh kg-1, lithium-sulfur batteries (LSBs) are anticipated to be among the next generation of high-energy-density storage technologies. However, the practical application of LSBs has been severely hampered by the significant shuttle effect and slow redox kinetics of polysulfides (LiPSs). To address the above problems, in this paper, the concept of quantum dots (QDs) was introduced to design and synthesize Mo2N QD-modified N-doped graphene nanosheets (marked as Mo2N-QDs@NG), which were used as separator modification materials for LSBs. The experimental results demonstrated that the introduction of Mo2N QDs avoids stacking of graphene sheets and provides more active sites for the conversion of LiPSs. Moreover, Mo2N enhances the chemical fixation and catalyzes the liquid-solid conversion of soluble LiPSs by forming Mo-S and Li-N bonds with LiPSs. Additionally, establishing Mo-C bonds with Mo2N, N-doped graphene sheets can facilitate the transport of electrons and ions and physically prevent the diffusion of LiPSs, thus creating a highly conducting carbon structure to support electrochemical reactions. Benefiting from the synergistic effect of chemical immobilization and catalysis of Mo2N QDs with the physical confinement of NG, Mo2N-QDs@NG-PP batteries exhibit enhanced electrochemical performance.

Developing Rapid-Charging Li-S Batteries via "Target Catalysis" of Cations and Anions Modified Electrocatalyst.

The shuttle effect and sluggish sulfur reduction reaction have resulted in significantly low efficiency and poor high current cycling stability in lithium-sulfur batteries, impeding their practical applications. To address these challenges, the introduction of Ni cations into MoS2 grown on reduced graphene oxide (MoS2/rGO) induces the formation of impurity energy levels between the conduction and valence bands of MoS2. Additionally, the introduction of anionic Se expands the interlayer spacing, enhances intrinsic conductivity, and improves ion diffusion rates. Simultaneously introducing anionic and cationic species into the MoS2/rGO causes the center of the d-band to shift upward, reducing the occupancy of electrons in antibonding orbitals. This modification leads to a rearrangement of the electronic structure of Mo, accelerating the redox reactions of lithium polysulfides. It particularly enhances the binding energy and lowers the conversion energy barrier of Li2S4. Consequently, the Li||S coin cell with the Ni-MoSSe/rGO cathode demonstrates an initial capacity of 446 mAh g-1 at 20 C, with a remarkable capacity retention of ≈96.7% after 200 cycles. Moreover, even under high sulfur loading conditions (6.45 mg cm-2) and a low electrolyte/sulfur ratio (5.4 µL mg-2), it maintains a high areal capacity of 6.42 mAh cm-2.

3D Conductive Nanostructure with the Lewis Acid–Base Interaction for High-Performance Lithium–Sulfur Batteries

3D Conductive Nanostructure with the Lewis Acid–Base Interaction for High-Performance Lithium–Sulfur Batteries

A covalently bonded, LiF-rich solid electrolyte interphase for Li metal batteries with superior low-temperature performance

The solid electrolyte interphase (SEI) layer plays a critical role in determining the performance of lithium metal batteries (LMBs). Here, we show that treating Li foils with 4,4,5,5,5-pentafluoropentanol (PFPO) results in the formation of a novel LiF-rich organic/inorganic SEI layer (designated as LiF-PO) that enhances the performance of LMBs. Compared to the native SEI layer that is electrochemically formed in LMBs, the LiF-PO SEI layer is mechanically robust, adopts a compact structure, and exhibits high Li+ conductivity. These features enable Li//Li symmetric cells to exhibit superior performance metrics, even at low temperatures, including inhibited Li dendrite growth, reduced polarization voltage, and elongated cycling lifetime. Moreover, compared to lithium–sulfur cells prepared using bare Li foils, the cells prepared using PFPO-treated Li foils also exhibit markedly improved performance at low temperatures in terms of specific capacity (796 mA h g−1 vs. 559 mA h g−1 at 0.1 C and −20 °C), rate capability (519 mA h g−1 vs. 222 mA h g−1 at 3 C and 0 °C), and cycling stability (504 mA h g−1 vs. 253 mA h g−1 at 0.1 C after 100 cycles at −20 °C). The lessons learned from our study establish new principles for designing high-performance SEI layers and may be extended to other types of metal batteries.

Delaying cyclization of polyacrylonitrile by boric acid for sulfurized poly(acrylonitrile) cathode materials

Sulfurized poly(acrylonitrile) (SPAN) has become one of the most promising cathode materials in rechargeable Lithium-Sulfur (Li-S) batteries due to their inhibited polysulfide dissolution, high sulfur utilization and excellent electrochemical performance via unique solid–solid conversion mechanism. However, the sulfur content of SPAN (<50 %) is still one of the significant reasons that restrict the electrochemical performance and practical applicability. In this paper, a small amount of boric acid (HBO) was introduced into the precursor of SPAN cathode materials easily before heat-treating, to increase the sulfur content and improve the electrochemical performance. Meanwhile, the results of first principles calculation suggested that the increase of sulfur content of SPAN was derived from the delayed cyclization of polyacrylonitrile (PAN) by HBO. We also discovered when the additive amount of HBO was 1.5 % of PAN mass, the SPAN cathode material possessed high sulfur content up to 54.24 wt%, and delivered prominent reversible electrochemical performances of 714 mAh/g at 0.2C and 734 mAh/g at 0.1C with high Coulombic efficiency. In summary, we proposed a simple and easy method to improve sulfur content and introduced a new strategy for the design of high-sulfur content and high-performance SPAN cathode materials.

Nd2O3/KB-coated separator constructs adsorption-catalytic bifunctional framework to improve lithium-sulfur battery performance

Nd2O3/KB-coated separator constructs adsorption-catalytic bifunctional framework to improve lithium-sulfur battery performance