A Facile Route to Flowerlike Bi2S3Constructed by Polycrystalline Nanoplates with Enhanced Electrochemical Properties

Bi2S3/C nanorods as efficient anode materials for lithium-ion batteries

Bi₂S₃ is a promising negative electrode material for lithium storage owing to its high theoretical capacity. Nevertheless, the capacity of Bi₂S₃ decays very rapidly upon Li cycling. Here, Bi₂S₃ and Bi₂S₃/C were successfully synthesized by a novel route. Sulfur powder as a kind of sulfur source reacted with a metal organic framework based on bismuth and trimesinic acid-Bi(BTC)(DMF)·DMF·(CH₃OH)₂ (denoted as Bi-BTC). Trimesic acid further acted as a new type of carbon source to synthesize the Bi₂S₃/C composite. The particle sizes of the composite were smaller than those of pure Bi₂S₃, showing the suppression of Bi₂S₃ aggregation. Charge-discharge performance and cyclability for both the Bi₂S₃ and Bi₂S₃/C composites in lithium-ion batteries were measured. Specifically, the specific capacities of Bi₂S₃/C and Bi₂S₃ reached 765 and 603 mA h g^-1, respectively, at 100 mA g^-1 after 100 cycles. Because of its high capacity and excellent cycle life, Bi₂S₃/C is a promising energy storage material.

Hierarchical self-assembled Bi2S3 hollow nanotubes coated with sulfur-doped amorphous carbon as advanced anode materials for lithium ion batteries

Bismuth sulfide (Bi2S3) is considered as a promising anode material for lithium ion batteries (LIBs) owing to its high theoretical specific capacity and intriguing reaction mechanism. However, capacity fading and cycling instability due to volume variation during the lithiation/delithiation process still remain a great challenge. Herein, we proposed a simple glucose assisted hydrothermal strategy and followed a post-treatment process to prepare hierarchical sulfur-doped carbon Bi2S3 (Bi2S3@SC) hollow nanotubes that self-assembled into sulfur-doped amorphous carbon coated Bi2S3 nanocrystals as building blocks. Glucose plays a decisive role in the formation process of Bi2S3 nanocrystals and subsequent self-assembly, forming Bi2S3@SC hollow nanotubes. The polysaccharide shell formed on the surface of Bi2S3 nanocrystals during the hydrothermal process was transformed into the sulphur-doped amorphous carbon layer after the post-treatment process. Electrochemical tests reveal that the resulting composites exhibit excellent electrochemical performance with a highly reversible cycling capacity of ∼950 mA h g-1 at a current density of 100 mA g-1, as well as a good rate capability and significantly enhanced cycling stability derived from their unique structural features, thus demonstrating the potential of Bi2S3@SC hollow nanotubes as high performance anode materials for LIBs. The analysis of electrochemical kinetics confirmed that the pseudocapacitive behavior dominates the overall storage process of Bi2S3@SC hollow nanotubes.

Engineering Bi2O3-Bi2S3 heterostructure for superior lithium storage

Bismuth oxide may be a promising battery material due to the high gravimetric (690 mAh g(-1)) and volumetric capacities (6280 mAh cm(-3)). However, this intrinsic merit has been compromised by insufficient Li-storage performance due to poor conductivity and structural integrity. Herein, we engineer a heterostructure composed of bismuth oxide (Bi2O3) and bismuth sulphide (Bi2S3) through sulfurization of Bi2O3 nanosheets. Such a hierarchical Bi2O3-Bi2S3 nanostructure can be employed as efficient electrode material for Li storage, due to the high surface areas, rich porosity, and unique heterogeneous phase. The electrochemical results show that the heterostructure exhibits a high Coulombic efficiency (83.7%), stable capacity delivery (433 mAh g(-1) after 100 cycles at 600 mA g(-1)) and remarkable rate capability (295 mAh g(-1) at 6 A g(-1)), notably outperforming reported bismuth based materials. Such superb performance indicates that constructing heterostructure could be a promising strategy towards high-performance electrodes for rechargeable batteries.

Nanostructured metal sulfides for energy storage

Advanced electrodes with a high energy density at high power are urgently needed for high-performance energy storage devices, including lithium-ion batteries (LIBs) and supercapacitors (SCs), to fulfil the requirements of future electrochemical power sources for applications such as in hybrid electric/plug-in-hybrid (HEV/PHEV) vehicles. Metal sulfides with unique physical and chemical properties, as well as high specific capacity/capacitance, which are typically multiple times higher than that of the carbon/graphite-based materials, are currently studied as promising electrode materials. However, the implementation of these sulfide electrodes in practical applications is hindered by their inferior rate performance and cycling stability. Nanostructures offering the advantages of high surface-to-volume ratios, favourable transport properties, and high freedom for the volume change upon ion insertion/extraction and other reactions, present an opportunity to build next-generation LIBs and SCs. Thus, the development of novel concepts in material research to achieve new nanostructures paves the way for improved electrochemical performance. Herein, we summarize recent advances in nanostructured metal sulfides, such as iron sulfides, copper sulfides, cobalt sulfides, nickel sulfides, manganese sulfides, molybdenum sulfides, tin sulfides, with zero-, one-, two-, and three-dimensional morphologies for LIB and SC applications. In addition, the recently emerged concept of incorporating conductive matrices, especially graphene, with metal sulfide nanomaterials will also be highlighted. Finally, some remarks are made on the challenges and perspectives for the future development of metal sulfide-based LIB and SC devices.