Interfacial Covalent Bonding Endowing Ti3 C2 -Sb2 S3 Composites High Sodium Storage Performance

Interfacial Coupling toward Bismuth Sulfide/MXene Heterostructures Empowering Reversible Magnesium Storage

Bismuth-based compounds based on conversion-alloying reactions of multielectron transfer have attracted extensive attention as alternative anode candidates for rechargeable magnesium batteries (rMBs). However, the inadequate magnesium storage capability induced by the sluggish kinetics, poor reversibility, and terrible structural stability impedes their practical utilization. Herein, monodispersed Bi2S3 anchored on MXene has been prepared via a simple self-assembly strategy to induce the interfacial bonding of Ti-S and Ti-O-Bi. Unique superiority, including good electrical conductivity, high mechanical strength, and rapid charge transfer, is cleverly integrated together in the Bi2S3/MXene heterostructures, which endowed heterostructures with enhanced magnesium storage performance. Density functional theory calculations combined with kinetic behavior analyses confirm the favorable charge transfer and low ion diffusion barrier in hybrids. Furthermore, a stepwise insertion-conversion-alloying reaction mechanism is revealed in depth by ex situ investigations, which may also account for promoting performance. This work provides significant inspirations for constructing ingenious multicompositional hybrids by strong interfacial coupling engineering toward high-performance energy storage devices.

Self-Assembled 2D VS2 /Ti3 C2 Tx MXene Nanostructures with Ultrafast Kinetics for Superior Electrochemical Sodium-Ion Storage

Constructing nanostructures with high structural stability and ultrafast electrochemical reaction kinetics as anodes for sodium-ion batteries (SIBs) is a big challenge. Herein, the robust 2D VS2 / Ti3 C2 Tx MXene nanostructures with the strong Ti─S covalent bond synthesized by a one-pot self-assembly approach are developed. The strong interfacial interaction renders the material of good structural durability and enhanced reaction kinetics. Meanwhile, the enlarged and few-layered MXene nanosheets can be easily obtained according to this interaction, providing a conductive network for sufficient electrolyte penetration and rapid charge transfer. As predicted, the VS2 /MXene nanostructures exhibit an extremely low sodium diffusion barrier confirmed by DFT calculations and small charge transfer impedance evidenced by electrochemical impedance spectroscopy (EIS) analysis. Therefore, the SIBs based on the VS2 /MXene electrode present first-class electrochemical performance with the ultrahigh average initial columbic efficiency of 95.08% and excellent sodium-ion storage capacity of 424.6 mAh g-1 even at 10 A g-1 . It also shows an outstanding sodium-ion storage capacity of 514.2 mAh g-1 at 1 A g-1 with a capacity retention of nearly 100% within 500 times high-rate cycling. Such impressive performance demonstrates the successful synthesis strategy and the great potential of interfacial interactions for high-performance energy storage devices.

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.

In-situ decoration of tin sulfide on Niobium carbide MXene with robust electronic coupling for improved sodium storage performance

Tin sulfide (SnS) has been considered as one of the most promising sodium storage materials because of its excellent electrochemical activity, low cost, and low-dimensional structure. However, owing to the serious volume change upon discharging/charging and poor electronic conductivity, the SnS-based electrodes often suffer from electrode pulverization and sluggish reaction kinetics, thus resulting in serious capacity fading and degraded rate capability. In this work, SnS nanoparticles uniformly distributed on the surface of the layered Niobium carbide MXene (SnS/Nb₂CT_x) were fabricated through a facile solvothermal approach followed by calcination, endowing the SnS/Nb₂CT_x with a three-dimensional interconnected framework as well as fast charge transfer. Benefitting from the excellent electronic/ionic conductivity, efficient buffering matrix, abundant active sites, and high sodium storage activity inherited from the structure design, the robust electronic coupling between SnS nanoparticle and Nb₂CT_x MXene results in excellent electrochemical output, which demonstrates superior reversible capacities of 479.6 (0.1 A/g up to 100 cycles) and 278.9 mAh/g (0.5 A/g up to 500 cycles) upon sodium storage, respectively. The excellent electrochemical performance manifests the promise of the combination of metal sulfides with Nb₂CT_x MXene to fabricate high-performance electrodes for sodium storage.

Terminal Group-Oriented Self-Assembly to Controllably Synthesize a Layer-by-Layer SnSe2 and MXene Heterostructure for Ultrastable Lithium Storage

Heterostructured materials integrate the advantages of adjustable electronic structure, fast electron/ions transfer kinetics, and robust architectures, which have attracted considerable interest in the fields of rechargeable batteries, photo/electrocatalysis, and supercapacitors. However, the construction of heterostructures still faces some severe problems, such as inferior random packing of components and serious agglomeration. Herein, a terminal group-oriented self-assembly strategy to controllably synthesize a homogeneous layer-by-layer SnSe₂ and MXene heterostructure (LBL-SnSe₂ @MXene) is designed. Benefitting from the abundant polar terminal groups on the MXene surface, Sn²⁺ is induced into the interlayer of MXene with large interlayer spacing, which is selenized in situ to obtain LBL-SnSe₂ @MXene. In the heterostructure, SnSe₂ layers and MXene layers are uniformly intercalated in each other, superior to other heterostructures formed by random stacking. As an anode for lithium-ion batteries, the LBL-SnSe₂ @MXene is revealed to possess strong lithium adsorption ability, the small activation energy for lithium diffusion, and excellent structure stability, thus achieving outstanding electrochemical performance, especially with high specific capacities (1311 and 839 mAh g^-1 for initial discharge and charge respectively) and ultralong cycling stability (410 mAh g^-1 at 5C even after 16 000 cycles). This work conveys an inspiration for the controllable design and construction of homogeneous layered heterostructures.

Bifunctional structure modulation of Sb-based sulfide for boosting fast and high-capacity sodium storage

A novel bimetallic sulfide CrSbS3 with both high sodium storage capacity and good rate performance is synthesized by introducing Cr atoms into the Sb2S3 structure.

Spontaneous Interface Healing by a Dynamic Liquid-Crystal Transition for High-Performance Perovskite Solar Cells

Low-temperature solution processing of thin-film semiconductors is more cost-effective than traditional vacuum processing; however, it leads to more defects during fast bulk crystallization and residual tensile stress. Herein, a new strategy of dynamic liquid-crystal transition (DLCT) is developed to solve these problems in one step. The design principle is used to suggest that the DLCT molecule should firstly interact with the perovskite grains in the bulk and meanwhile go through a dynamic transition to spontaneously heal the interface. A thermotropic LC molecule (CBO6SS6OCB) is then designed to demonstrate the strategy. The LC interacting with perovskite colloid forms an intermediate adduct to retard the crystallization. The annealing processes stimulate the concentrated LC solid, causing it to flow to the electron transport layer to release the residual stress to attain improved electron extraction. Consequently, the device efficiency is increased to 24.38%, where its V_OC of 1.184 V is among the best for the formamidine-based perovskite solar cells. Furthermore, the ambient stability (93.0% of initial efficiency after 2000 h of aging) and light stability (96.3% of initial efficiency after 500 h of aging) are much improved. This work conceives a new engineering of additive phase transition for high-performance perovskite solar cells.