Core@shell and lateral heterostructures composed of SnS and NbS2

Vanadium Intercalation into Niobium Disulfide to Enhance the Catalytic Activity for Lithium-Sulfur Batteries

Despite their high specific energy and great promise for next-generation energy storage, lithium-sulfur (Li-S) batteries suffer from polysulfide shuttling, slow redox kinetics, and poor cyclability. Catalysts are needed to accelerate polysulfide conversion and suppress the shuttling effect. However, a lack of structure-activity relationships hinders the rational development of efficient catalysts. Herein, we studied the Nb-V-S system and proposed a V-intercalated NbS₂ (Nb₃VS₆) catalyst for high-efficiency Li-S batteries. Structural analysis and modeling revealed that undercoordinated sulfur anions of [VS₆] octahedra on the surface of Nb₃VS₆ may break the catalytic inertness of the basal planes, which are usually the primary exposed surfaces of many 2D layered disulfides. Using Nb₃VS₆ as the catalyst, the resultant Li-S batteries delivered high capacities of 1541 mAh g^-1 at 0.1 C and 1037 mAh g^-1 at 2 C and could retain 73.2% of the initial capacity after 1000 cycles. Such an intercalation-induced high activity offers an alternative approach to building better Li-S catalysts.

Ultrastable Cu2+ Intercalation Chemistry Based on a Niobium Sulfide Nanosheet Cathode for Advanced Aqueous Storage Devices

Exploring stable and durable cathodes for cost-effective reversible aqueous batteries is highly desirable for grid-scale energy storage applications, but significant challenges remain. Herein, we disclosed an ultrastable Cu²⁺ intercalation chemistry in mass-produced exfoliated NbS₂ nanosheets to build ultralong lifespan aqueous batteries with cost advantages. Anisotropic interplanar expansion of NbS₂ lattices balanced dynamic Cu²⁺ incorporation and the highly reversible redox reaction of Nb⁴⁺/Nb^(4-δ)+ couple were illuminated by operando synchrotron X-ray diffraction and energy dispersive X-ray absorption spectroscopy, affording an extraordinary capacity of approximately 317 mAh g^-1 at 1 A g^-1 and a good stability of 92.2% capacity retention after 40000 cycles at 10 A g^-1. Impressively, a budget NbS₂||Fe hybrid ion cell involving an aqueous electrolyte/Fe-metal anode is established and provides a reliable energy supply of 225.4 Wh kg^-1 at 750 W kg^-1, providing insights for building advanced aqueous battery systems for large-scale applications.

Hydroxyl-modified Nb4C3Tx MXene@ZnIn2S4 sandwich structure for photocatalytic overall water splitting

Herein, a hydroxyl-modified MXene@ZnIn₂S₄ (Nb₄C₃T_x MXene@ZIS-OH) overall water splitting photocatalyst with a sandwich structure was prepared through an in-situ growth strategy and peroxyl plasma post-treatment. The Nb₄C₃T_x MXene@ZIS-OH exhibits outstanding catalytic performance, which generates the release rates of hydrogen (53.8 μmol g^-1h^-1) and oxygen (26.7 μmol g^-1h^-1) from the water under visible light irradiation. After four photocatalytic cycling, the photocatalytic overall water splitting activity of Nb₄C₃T_x MXene@ZIS-OH is still 95.9% of the initial activity, which indicates that Nb₄C₃T_x MXene@ZIS-OH exhibits excellent cycling stability. Notably, the Nb₄C₃T_x MXene@ZIS-OH achieves an AQY of 1.2% for the overall photocatalytic water splitting at 380 nm. The sandwich structure and matched heterointerface between high work function Nb₄C₃T_x MXene and ZnIn₂S₄ nanosheets promote the electron transport, inhibit the charge recombination, and separate the generated H₂ and O₂ with effectiveness. Importantly, the Finite-Difference Time-Domain (FDTD) simulation suggests the hydroxyl groups on the surface of ZnIn₂S₄ could increase the hydrophilicity of photocatalyst and capture the holes generated by photoexcitation, thereby promoting the separation of electron-hole pairs rapidly. This work presents a successful example of constructing overall water splitting photocatalysts by energy level regulation, structure design and functional group modification.

Heterostructure engineering of ultrathin SnS2/Ti3C2Tx nanosheets for high-performance potassium-ion batteries

Layered metal sulfides are considered as promising candidates for potassium ion batteries (KIBs) owing to the unique interlayer passages for ion diffusion. However, the insufficient electronic conductivity, inevitable volume expansion, and sulfur loss hinder the promotion of K-ion storage performance. Herein, few-layered Ti₃C₂T_x nanosheets were selected as the multi-functional substrate for cooperating few-layered SnS₂ nanosheets, constructing SnS₂/Ti₃C₂T_x hetero-structural nanosheets (HNs) with the thickness as thin as about 5 nm. In this configuration, the formed Ti-S bonds provide robust interaction between SnS₂ and Ti₃C₂T_x nanosheets, which hinders the agglomeration of SnS₂ and the restack of Ti₃C₂T_x, endowing the hybrid material with robust nanostructure. Thus, the shortcomings of the SnS₂ anode are muchly relieved. In this way, the as-prepared SnS₂/Ti₃C₂T_x HNs electrode delivers reversible capacities of 462.1 mAh g^-1 at 0.1 A g^-1 and 166.1 mAh g^-1 at 2.0 A g^-1, respectively, and a capacity of 85.5 mAh g^-1 is remained even after 460 cycles at 2.0 A g^-1. These results are superior to those of the counterpart electrode, confirming aggressive promotion of K-ion storage performance of SnS₂ anode brought by the cooperation of Ti₃C₂T_x, and presenting a reliable strategy to improve the electrochemical performance of sulfide anodes.