Advanced Anode Materials for Rechargeable Sodium-Ion Batteries

Rechargeable sodium-ion batteries (SIBs) have been considered as promising energy storage devices owing to the similar "rocking chair" working mechanism as lithium-ion batteries and abundant and low-cost sodium resource. However, the large ionic radius of the Na-ion (1.07 Å) brings a key scientific challenge, restricting the development of electrode materials for SIBs, and the infeasibility of graphite and silicon in reversible Na-ion storage further promotes the investigation of advanced anode materials. Currently, the key issues facing anode materials include sluggish electrochemical kinetics and a large volume expansion. Despite these challenges, substantial conceptual and experimental progress has been made in the past. Herein, we present a brief review of the recent development of intercalation, conversion, alloying, conversion-alloying, and organic anode materials for SIBs. Starting from the historical research progress of anode electrodes, the detailed Na-ion storage mechanism is analyzed. Various optimization strategies to improve the electrochemical properties of anodes are summarized, including phase state adjustment, defect introduction, molecular engineering, nanostructure design, composite construction, heterostructure synthesis, and heteroatom doping. Furthermore, the associated merits and drawbacks of each class of material are outlined, and the challenges and possible future directions for high-performance anode materials are discussed.

Structural and Electronic Properties of SnO Downscaled to Monolayer

Two-dimensional (2D) SnO is a p-type semiconductor that has received research and industrial attention for device-grade applications due to its bipolar conductivity and transparent semiconductor nature. The first-principles investigations based on the generalized gradient approximation (GGA) level of theory often failed to accurately model its structure due to interlayer Van der Waals interactions. This study is carried out to calculate structural and electronic properties of bulk and layered structures of SnO using dispersion correction scheme DFT+D3 with GGA-PBE to deal with the interactions which revealed good agreement of the results with reported data. The material in three-dimensional bulk happened to be an indirect gap semiconductor with a band gap of 0.6 eV which is increased to 2.85 eV for a two-dimensional monolayer structure. The detailed analysis of the properties demonstrated that the SnO monolayer is a promising candidate for future optoelectronics and spintronics devices, especially thin film transistors.

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.

Cumulative effects of doping on Sn3O4 structure and electrode performance for rechargeable sodium-ion batteries

Interconnected nanoflakes of modified Sn3O4 are capable of providing fast carrier transmission dynamics and outstanding structural integrity, suggesting the feasibility of the current framework for sodium-ion storage.

The rational design of nickel-cobalt selenides@selenium nanostructures by adjusting the synthesis environment for high-performance sodium-ion batteries

Different selenization products (from the perspectives of micromorphology and sodium storage performance) can be obtained via regulating the selenization environment.

[Co3(μ3-O)]-Based Metal-Organic Frameworks as Advanced Anode Materials in K- and Na-Ion Batteries

A new metal-organic framework {(Me₂NH₂)₂[Co₃(μ₃-O)(btb)₂(py)(H₂O)]·(DMF)₂(H₂O)₂}_n (Cobtbpy) was solvothermal synthesized (H₃btb = 1,3,5-tri(4-carboxylphenyl)benzene, py = pyridine, DMF = N,N-dimethylformamide). Cobtbpy shows a (3,6)-connected rtl 3D network with a point symbol of (4·6²)₂(4²·6¹⁰·8³) based on the [Co₃(μ₃-O)] clusters. The obtained Cobtbpy has stable, accessible, dense active sites and can be applied in the potassium- and sodium-ion batteries. Through mixing with single-walled carbon nanotubes, the prepared composite anode material Cobtbpy-0.9 achieved a high reversible capability, delivering 416 mAh/g in the potassium-ion batteries and 379 mAh/g in the sodium-ion batteries at 0.05 A/g. The outstanding properties of Cobtbpy-0.9 in the batteries demonstrated that this MOFs-based carbon composite is a highly desirable electrode material candidate for high-performance potassium- and sodium-ion batteries.

Waste utilization of crab shell: 3D hierarchical porous carbon towards high-performance Na/Li storage

Waste into wealth: an advanced anode material with a unique 3D porous structure derived from discarded crab shells.