Flexible SnS2/CNTs/porous Cu tube textile anode for enhanced sodium-ion batteries

Induced Bimetallic Sulfide Growth with Reduced Graphene Oxide for High-Performance Sodium Storage

Metal sulfide has been considered an ideal sodium-ion battery (SIB) anode material based on its high theoretical capacity. Nevertheless, the inevitable volume expansion during charge-discharge processes can lead to unsatisfying electrochemical properties, which limits its further large-scale application. In this contribution, laminated reduced graphene oxide (rGO) successfully induced the growth of SnCoS₄ particles and self-assembled into a nanosheet-structured SnCoS₄@rGO composite through a facile solvothermal procedure. The optimized material can provide abundant active sites and facilitate Na⁺ ion diffusion due to the synergistic interaction between bimetallic sulfides and rGO. As the anode of SIBs, this material maintains a high capacity of 696.05 mAh g^-1 at 100 mA g^-1 after 100 cycles and a high-rate capability of 427.98 mAh g^-1 even at a high current density of 10 A g^-1. Our rational design offers valuable inspiration for high-performance SIB anode materials.

Rational Design Hierarchical SnS2 Uniformly Adhered to Three-Sided Carbon Active Sites to Enhance Sodium Storage

Reducing material accumulation and designing reasonable sizes are critical strategies for increasing the rate and cycling stability of electrode materials. Herein, we presented a double-walled hollow carbon spheres (DWHCSs) loading strategy for achieving ultrafine SnS₂ nanosheet adhesion by utilizing three-sided active sites of the interior/exterior carbon walls. The structure effectively shortened the electron/ion transport path, increased the effective contact between electrolyte and electrode material, and promoted ion diffusion kinetics. Furthermore, the hollow structure can adapt to the volume change of the electrode during the cycle, preventing active substances from draining. Based on the above advantages, SnS₂@DWHCSs as an anode material for sodium ion batteries (SIBs) exhibited a distinguished reversible capacity of 665.7 mA h g^-1 at 2 A g^-1 after 1000 cycles, and a superior rate ability of 377.6 mA h g^-1 at an ultrahigh rate of 10 A g^-1. The outstanding electrochemical performance revealed that the structure exhibited a broad application prospect in the field of energy storage and provided a reference for the rational design of other 2D materials.

A novel interlayer-expanded tin disulfide/reduced graphene oxide nanocomposite as anode material for high-performance sodium-ion batteries

As a kind of negative electrode material for sodium-ion batteries (SIBs), tin-based active compounds have attracted numerous research efforts in recent years due to relatively high theoretical capacity. However, sluggish reaction kinetics for large-radius sodium ions hinders the practical application of layered tin-based anodes such as tin disulfide (SnS₂) in SIBs. In this study, polyethylene glycol (PEG) is introduced as an intercalant and reduced graphene oxide (rGO) is utilized as the substrate to prepare a novel PEG-SnS₂/rGO composite with expanded layer spacing (0.921 nm) through a facile hydrothermal process. SnS₂ flakes in a size range of 50-100 nm are uniformly grown on the graphene sheet, the CS covalent bonding demonstrates a tight connection between the active SnS₂ particles and the graphene skeleton, which is conductive to convenient charge transfer during the electrochemical process. Owing to the significantly improved sodium ions transport kinetics and fast electronic conductive network, the PEG-SnS₂/rGO composite presents a high capacitance contribution of 90.69% at a scan rate of 0.6 mV s^-1. It delivers a high reversible capacity of 960.6 mAh g^-1 at 0.1 A g^-1, good cycling performance with 770 mAh g^-1 remained after 100 charge/discharge cycles, and excellent rate capability with an ultrahigh capacity of 720 mAh g^-1 at 5 A g^-1. This work provides new insights into the design of a kinetically favorable anode material for SIBs.