Celgard-supported LiX zeolite membrane as ion-permselective separator in lithium sulfur battery

In-Situ Grafting Strategy Enables Functional Separator for Advanced Lithium-Sulfur Batteries

A functional separator is developed by in-situ grafting nickel tetraaminophthalocyanine (NiTAPc) onto the surface of polypropylene (PP). It is applied to inhibit the shuttle effect of polysulfides (PSs) in lithium-sulfur(Li-S) batteries. The characterization results showed that NiTAPc is highly dispersed and uniformly grafted onto PP separator. In-situ grafting strategy effectively mitigates the self-agglomeration issue associated with NiTAPc and enhances the exposure of catalytically active Ni-N4 sites. These sites exhibit excellent adsorption and conversion capabilities for PSs. This is consistent with the results of theory calculations, which indicate that the presence of NiTAPc can reduce the delithiation energy barrier associated with Li2S conversion. Owing to the excellent inhibition ability of NiTAPc on the shuttle effect of PSs, the Li-S battery employing a PP-NiTAPc separator demonstrates excellent cycle stability. It shows an initial specific capacity of 1256.5 mAh g-1 at 0.1 C, and a capacity retention of 582.4 mAh g-1 after 500 cycles at 1 C, showcasing a minimal decay rate of 0.0547% per cycle. The strategy adopted in this study offers valuable insights for the development of modified separators for rechargeable batteries and other energy storage fields.

Microporous Materials in Polymer Electrolytes: The Merit of Order

Solid-state batteries (SSBs) have garnered significant attention in the critical field of sustainable energy storage due to their potential benefits in safety, energy density, and cycle life. The large-scale, cost-effective production of SSBs necessitates the development of high-performance solid-state electrolytes. However, the manufacturing of SSBs relies heavily on the advancement of suitable solid-state electrolytes. Composite polymer electrolytes (CPEs), which combine the advantages of ordered microporous materials (OMMs) and polymer electrolytes, meet the requirements for high ionic conductivity/transference number, stability with respect to electrodes, compatibility with established manufacturing processes, and cost-effectiveness, making them particularly well-suited for mass production of SSBs. This review delineates how structural ordering dictates the fundamental physicochemical properties of OMMs, including ion transport, thermal transfer, and mechanical stability. The applications of prominent OMMs are critically examined, such as metal-organic frameworks, covalent organic frameworks, and zeolites, in CPEs, highlighting how structural ordering facilitates the fulfillment of property requirements. Finally, an outlook on the field is provided, exploring how the properties of CPEs can be enhanced through the dimensional design of OMMs, and the importance of uncovering the underlying "feature-function" mechanisms of various CPE types is underscored.

In-Situ Transformation of Li-ABW Zeolites Based on Li-Geopolymer

Lithium batteries, as energy storage devices, are playing an increasingly important role in human society. As a result of the low safety of the liquid electrolyte in batteries, more attention has been paid to solid electrolytes. Based on the application of lithium zeolite in a Li-air battery, a non-hydrothermal conversed lithium molecular sieve was prepared. In this paper, in-situ infrared spectroscopy, together with other methods, was used to characterize the transformation process of geopolymer-based zeolite. The results showed that Li/Al = 1.1 and 60 °C were the best transformation conditions for the Li-ABW zeolite. On this basis, the geopolymer was crystallized after 50 min of reaction. This study proves that the formation of geopolymer-based zeolite occurs earlier than the solidification of the geopolymer and shows that the geopolymer is a good precursor for zeolite conversion. At the same time, it comes to the conclusion that the formation of zeolite will have an impact on the geopolymer gel. This article provides a simple preparation process for lithium zeolite, explores the preparation process and mechanism, and provides a theoretical basis for future applications.

Tin disulfide embedded on porous carbon spheres for accelerating polysulfide conversion kinetics toward lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered promising candidates for next-generation advanced energy storage systems due to their high theoretical capacity, low cost and environmental friendliness. However, the severe shuttle effect and weak redox reaction severely restrict the practical application of Li-S batteries. Herein, a functional catalytic material of tin disulfide on porous carbon spheres (SnS₂@CS) is designed as a sulfur host and separator modifier for lithium-sulfur batteries. SnS₂@CS with high electrical conductivity, high specific surface area and abundant active sites can not only effectively improve the electrochemical activity but also accelerate the capture/diffusion of polysulfides. Theoretical calculations and in situ Raman also demonstrate that SnS₂@CS can efficiently adsorb and catalyse the rapid conversion of polysulfides. Based on these advantages, the SnS₂@CS-based Li-S battery delivers an excellent reversible capacity of 868 mAh/g at 0.5C (capacity retention of 96 %), a high rate capability of 852 mAh/g at 2C, and a durable cycle life with an ultralow capacity decay rate of 0.029 % per cycle over 1000 cycles at 2C. This work combines the design of sulfur electrodes and the modification of separators, which provides an idea for practical applications of Li-S batteries in the future.

Tg-C3N4-coated functional separator as polysulfide barrier of high-performance lithium-sulfur batteries

Lithium sulfur (Li-S) battery is considered as a promising alternative for the development of battery technologies. However, the shuttle effect seriously limits its practical use. Herein, hollow tubular graphene-like carbon nitride (Tg-C₃N₄) is synthesized and utilized as a functional interlayer to inhibit shuttling effect and promote catalytic kinetics. Both experiments and DFT calculations together suggest that N-doping enhances the electron transfers between Tg-C₃N₄and LiPSs, leading to improved chemical adsorptions and catalytic effects towards the redox conversions of the active sulfur species. Besides, Tg-C₃N₄delivers a unique hollow tubular architecture with massive ion transfer pathways and fully exposed active interfaces. In addition, the abundant C-N heteroatomic structures also impose strong chemical immobilization toward lithium polysulfides. Benefiting from these unique superiorities, the cell with the Tg-C₃N₄-modified separator exhibits a reversible capacity of 494 mAh g^-1after 500 cycles at 1 C with a negligible capacity decay of 0.085% per cycle, indicating an efficient strategy toward high-performance modified separators.

A multifunctional UiO-66@carbon interlayer as an efficacious suppressor of polysulfide shuttling for lithium-sulfur batteries

Restraining the shuttle effect in lithium-sulfur (Li-S) battery is crucial to realize its practical application. In this work, a UiO-66@carbon (UiO-66@CC) interlayer was developed for Li-S battery by growing a continuous UiO-66 film on carbon cloth. The continuous UiO-66 crystal layer contributes to provide sufficient adsorptive and catalytic sites for efficient adsorption and catalytic conversion towards polysulfides. Moreover, the hydrophilic property of UiO-66 material ensures the full infiltration of electrolyte and accelerates the transportation of lithium ions. Profiting from the above advantages of the proposed interlayer, the shuttle effect is effectively inhibited and a fast redox kinetic is also realized. Accordingly, the Li-S battery using UiO-66@CC delivers a specific capacity of 1228.9 mAh g^-1at 0.2 C with a nearly 100% capacity retention after 100 cycles, and the first specific capacity is 1033.1 mAh g^-1at 1.0 C with a decay rate of 0.07% over 600 cycles. Meanwhile, UiO-66@CC interlayer also has an excellent rate performance with a specific capacity of 535.9 mAh g^-1at 5.0 C and a high area capacity of 6.2 mAh cm^-2at increased sulfur loading (8.15 mg cm^-2).

Oxygen Vacancy-Rich Mixed-Valence Cerium MOF: An Efficient Separator Coating to High-Performance Lithium-Sulfur Batteries

Mixed-valence metal-organic frameworks (MOFs) have exhibited unique potential in fields such as catalysis and gas separation. However, it is still an open challenge to prepare mixed-valence MOFs with isolated Ce(IV, III) arrays due to the easy formation of Ce^III under the synthetic conditions for MOFs. Meanwhile, the performance of Li-S batteries is greatly limited by the fatal shuttle effect and the slow transmission rate of Li⁺ caused by the inherent characteristics of sulfur species. Here, we report a mixed-valence cerium MOF, named CSUST-1 (CSUST stands for Changsha University of Science and Technology), with isolated Ce(IV, III) arrays and abundant oxygen vacancies (OVs), synthesized as guided by the facile and elaborate kinetic stability study of UiO-66(Ce), to work as an efficient separator coating for circumventing both issues at the same time. Benefiting from the synergistic function of the Ce(IV, III) arrays (redox couples), the abundant OVs, and the open Ce sites within CSUST-1, the CSUST-1/CNT composite, as a separator coating material in the Li-S battery, can remarkably accelerate the redox kinetics of the polysulfides and the Li⁺ transportation. Consequently, the Li-S cell with the CSUST-1/CNT-coated separator exhibited a high initial specific capacity of 1468 mA h/g at 0.1 C and maintained long-term stability for a capacity of 538 mA h/g after 1200 cycles at 2 C with a decay rate of only 0.037% per cycle. Even at a high sulfur loading of 8 mg/cm², the cell with the CSUST/CNT-coated separator still demonstrated excellent performance with an initial areal capacity of 8.7 mA h/cm² at 0.1 C and retained the areal capacity of 6.1 mA h/cm² after 60 cycles.