Interfacial engineering enables Bi2S3@N-doped carbon nanospheres towards high performance anode for lithium-ion batteries

Microstructure modulation improving the stability performance of a Bi anode for lithium-ion batteries

Metallic Bi is a classic metal-type anode material characterized by its high volume-specific capacity (3785 mA h cm-3) and theoretical specific capacity (386 mA h g-1). However, during the charge and discharge processes of the battery, Bi undergoes significant volume expansion and contraction, which leads to a notable decline in battery performance. In this work, to suppress the volume expansion of bismuth and enhance battery performance and stability, a Bi-metal-organic-framework (Bi-MOF) is utilized as a precursor and combined with an organic polymerization coating process, followed by calcination, to obtain a double-carbon-coated lamellar structure (Bi/C@CPpy). The coated carbon layers inhibit the agglomeration of Bi particles and mitigate volume changes during charge-discharge cycles. After 100 cycles at 0.1 A g-1, Bi/C@CPpy maintains a specific capacity of 526.4 mA h g-1. Even after 900 extended cycles, it retains a specific capacity of 255.6 mA h g-1 at 0.5 A g-1. In situ XRD is employed to analyze the Li+ storage mechanism. Furthermore, a full cell with Li1.2Ni0.13Co0.13Mn0.64O2 as the cathode and a Bi/C@CPpy-based anode achieves a capacity of 104.3 mA h g-1 after 100 cycles at a current density of 0.05 A g-1. This approach provides valuable insights into the precise structural design and preparation of high-performance rechargeable battery alloy negative electrode materials.

Coordination Regulation Strategy in Fabricating Bi2S3@CNFs Composites with Uniform Dispersion for Robust Sodium Storage

To solve large volume change and low conductivity of Bi2S3-based anodes, a coordination regulation strategy is proposed to prepare Bi2S3 nanoparticles dispersed in carbon fiber (Bi2S3@CNF) composites. It has been discovered that introducing trimesic acid as a ligand can significantly improve the loading and dispersion of Bi3+ in polyacrylonitrile fibers. The results exhibit that Bi2S3 nanoparticles of 200-300 nm are uniformly anchored on the superficial surface layer of CNFs, and Bi2S3 nanoparticles of about 20 nm are evenly dispersed in the interior of CNFs. Assessed as sodium-ion batteries' anode material, the discharge capacity of the Bi2S3@CNF anode in the second cycle is 669.3 mAh g-1 at 0.1 A g-1 and still retains 620.2 mAh g-1 after 100 cycles, with the capacity retention rate of 92.7%. Even at 0.5 A g-1, the specific capacity of the second cycle is 432.99 mAh g-1, which still keeps 400.9 mAh g-1 after 800 cycles, with a retention rate of 92.5%. The excellent cycle stability is mainly attributed to the uniform distribution of small Bi2S3 nanoparticles in CNFs providing abundant active sites, preventing side reactions, relieving volume expansion, improving the electrical conductivity, and accelerating the electrochemical reaction kinetics.

Oxygen Self-Doping Bi2S3@C Spheric Successfully Enhanced Long-Term Performance in Lithium-Ion Batteries

High theoretical capacity of Bi2S3 propels it toward an ideal anode material for lithium-ion batteries (LIBs); however, rapid capacity attenuation and poor long-term stability are major barriers to widespread application. In this work, an oxygen self-doping strategy was utilized to synthesize O-Bi2S3@C, significantly increasing the amount of active sites for lithium-ion storage. Meanwhile, sulfur vacancies were formed to improve the electrical conductivity and ionic transport efficiency, enhance the long-term stability, and accelerate the electrochemical kinetics of Bi2S3@C. O-BSC-S1:3 anode exhibits a reversible capacity of 673.1 mAh g-1 at 0.2 A g-1. It retains a long-term capacity of 596.3 mAh g-1 over 1100 cycles at a high density of 3 A g-1 in LIBs. Moreover, the installed O-Bi2S3@C//LiCoO2 full battery offers exceptional reversible capacity and remarkable cyclability (325.2 mAh g-1 after 200 cycles) at 0.2 A g-1. The combined strategy of oxygen self-doping and sulfur vacancy effectively enhances the reversible capacity and cycling life of Bi2S3, providing an approach for the design of high-performance transition metal sulfide anodes for LIBs.

Encapsulating Bi Nanoparticles in Reduced Graphene Oxide with Strong Interfacial Bonding toward Advanced Potassium Storage

Bismuth (Bi) is regarded as a promising anode material for potassium ion batteries (PIBs) due to its high theoretical capacity, but the huge volume expansion during potassiation and intrinsic low conductivity cause poor cycle stability and rate capability. Herein, a unique Bi nanoparticles/reduced graphene oxide (rGO) composite is fabricated by anchoring the Bi nanoparticles over the rGO substrate through a ball-milling and thermal reduction process. As depicted by the in-depth XPS analysis, strong interfacial Bi-C bonding can be formed between Bi and rGO, which is beneficial for alleviating the huge volume expansion of Bi during potassiation, restraining the aggregation of Bi nanoparticles and promoting the interfacial charge transfer. Theoretical calculation reveals the positive effect of rGO to enhance the potassium adsorption capability and interfacial electron transfer as well as reduce the diffusion energy barrier in the Bi/rGO composite. Thereby, the Bi/rGO composite exhibits excellent potassium storage performances in terms of high capacity (384.8 mAh g-1 at 50 mA g-1), excellent cycling stability (197.7 mAh g-1 after 1000 cycles at 500 mA g-1 with no capacity decay) and superior rate capability (55.6 mAh g-1 at 2 A g-1), demonstrating its great potential as an anode material for PIBs.

Constructing three-dimensional N-doped carbon coating silicon/iron silicide nanoparticles cross-linked by carbon nanotubes as advanced anode materials for lithium-ion batteries

Silicon (Si), have been considered as promising anode material for lithium-ion batteries (LIBs), due to its high theoretical specific capacity of 4200 mAh g-1. However, the poor electrical conductivity and large volume change during lithiation/delithiation process, resulting in poor cycling stability, and seriously hindered the practical application in LIBs. Herein, a multiple Si/FexSiy@NC/CNTs composite is synthesized and investigated as advanced anode materials for LIBs via a simple one-step method. Such multiple Si/FexSiy@NC/CNTs composite has several merits including the FexSiy can not only accommodate the huge volume change of Si nanoparticles, but also enhance the conductivity upon discharge/charge process. Furthermore, the in-situ growth CNTs may help establish a long-range conductivity, and the Nitrogen-doped carbon (NC) layer can further improve the conductivity of Si, as well as inhibit the direct contract between electrolyte and Si during cycling process. Accordingly, the Si/FexSiy@NC/CNTs-1 exhibits excellent cycling stability (a high capacity of 994.4 mAh g-1 is maintained at 1.0 A g-1 after 600cycles) and outstanding rate capability (a suitable capacity of 441.7 mAh g-1 was obtained even at 5.0 A g-1). Moreover, the assembled full cell can achieve a capacity of 141.4 mAh g-1 after 65 cycles at 1.0C, exhibiting outstanding cycling stability. This work provides a prospective way for the commercial production of high-performance Si-based anode materials for LIBs.

Synthesis of Nanostructured Bismuth Sulfide with Controllable Morphology for Advanced Lithium/Sodium-Ion Storage

Rational design of electrode materials with an excellent structure and morphology is crucial for improving electrochemical properties. Herein, various unique nanostructured Bi₂S₃ materials with controllable morphology were obtained through a simple and efficient oil bath reaction strategy. Bi₂S₃ with different morphologies can be obtained by regulating the polarity of solvent, and the lattice spacing can also be adjusted. The Bi₂S₃ nanomaterials obtained with ethanol as solvent (BS-3) show a three-dimensional nanoflower-like structure assembled with porous layers. The unique structure facilitates the transport of ions and accommodates the volume variation of Bi₂S₃ during energy storage. Consequently, BS-3 nanoflowers exhibited superior cycling stability and excellent high-rate capability for lithium storage (maintained a high capacity of 923.8 mA h g^-1 after 950 cycles at 1.0 A g^-1) and excellent sodium storage. We provide guidance for precise synthesis and energy storage application of Bi₂S₃ nanomaterials.

Synthesis of core-shell ZnS@C micron-rods as advanced anode materials for lithium ion batteries

Zinc sulfide (ZnS), is considered as a candidate anode materials to replace commercial graphite anode for high performance LIBs. However, the huge volume change during the lithiation/delithiation process, lead to...