Rodlike Sb2Se3 Wrapped with Carbon: The Exploring of Electrochemical Properties in Sodium-Ion Batteries

Interfacial SbOC bond and structural confinement synergistically boosting the reaction kinetics and reversibility of Sb2Se3/NC nanorods anode for sodium storage

Antimony selenide (Sb2Se3) has been considered as a prospective material for sodium-ion batteries (SIBs) because of its large theoretical capacity. Whereas, grievous volume expansion caused by the conversion-alloying reaction leads to fast capacity decay and inferior cycle stability. Herein, the confined Sb2Se3 nanorods in nitrogen-doped carbon (Sb2Se3/NC) with interfacial chemical bond is designed to further enhance sodium storage properties of Sb2Se3. The robust enhancing effect of interfacial SbOC bonds can significantly promote electron transfer, Na+ ions diffusion kinetics and alloying reaction reversibility, combining the synergistic effect of the unique confinement structure of N-doped carbon shells can efficiently alleviate the volume change to ensure the structural integrity. Moreover, in-situ X-ray diffraction reveals intercalation/de-intercalation, conversion/reversed conversion reaction and alloying/de-alloying reaction mechanisms, and the kinetics analysis demonstrates the diffusion-controlled to contribute high capacity. As a result, Sb2Se3/NC anode delivers a high reversible capacity of 612.6 mAh/g at 0.1 A/g with a retentive specific capacity of 471.4 mAh/g after 1000 cycles, and long-cycle durability of over 2000 cycle with the reversible capacities of 371.1 and 297.3 mAh/g at 1 and 2 A/g are achieved, respectively, and an good rate capability. This distinctive interfacial chemical bonds and confinement effect design shows potential applications in the improved conversion/alloying-type materials for SIBs.

Amine-Aldehyde Condensation-Derived N-Doped Hard Carbon Microspheres for High-Capacity and Robust Sodium Storage

Hard carbon is generally accepted as the choice of anode material for sodium-ion batteries. However, integrating high capacity, high initial Coulombic efficiency (ICE), and good durability in hard carbon materials remains challenging. Herein, N-doped hard carbon microspheres (NHCMs) with abundant Na+ adsorption sites and tunable interlayer distance are constructed based on the amine-aldehyde condensation reaction using m-phenylenediamine and formaldehyde as the precursors. The optimized NHCM-1400 with a considerable N content (4.64%) demonstrates a high ICE (87%), high reversible capacity with ideal durability (399 mAh g-1 at 30 mA g-1 and 98.5% retention over 120 cycles), and decent rate capability (297 mAh g-1 at 2000 mA g-1 ). In situ characterizations elucidate the adsorption-intercalation-filling sodium storage mechanism of NHCMs. Theoretical calculation reveals that the N-doping decreases the Na+ adsorption energy on hard carbon.

Scalable Synthesis of Selenide Solid-State Electrolytes for Sodium-Ion Batteries

Solid-state sodium-ion batteries employing superionic solid-state electrolytes (SSEs) offer low manufacturing costs and improved safety and are considered to be a promising alternative to current Li-ion batteries. Solid-state electrolytes must have high chemical/electrochemical stability and superior ionic conductivity. In this work, we employed precursor and solvent engineering to design scalable and cost-efficient solution routes to produce air-stable sodium selenoantimonate (Na3SbSe4). First, a simple metathesis route is demonstrated for the production of the Sb2Se3 precursor that is subsequently used to form ternary Na3SbSe4 through two different routes: alcohol-mediated redox and alkahest amine-thiol approaches. In the former, the electrolyte was successfully synthesized in EtOH by using a similar redox solution coupled with Sb2Se3, Se, and NaOH as a basic reagent. In the alkahest approach, an amine-thiol solvent mixture is utilized for the dissolution of elemental Se and Na and further reaction with the binary precursor to obtain Na3SbSe4. Both routes produced electrolytes with room temperature ionic conductivity (∼0.2 mS cm-1) on par with reported performance from other conventional thermo-mechanical routes. These novel solution-phase approaches showcase the diversity and application of wet chemistry in producing selenide-based electrolytes for all-solid-state sodium batteries.

Synergistically boosting reaction kinetics and suppressing polyselenide shuttle effect by Ti3C2Tx/Sb2Se3 film anode in high-performance sodium-ion batteries

Antimony selenide (Sb₂Se₃), with rich resources and high electrochemical activity, including in conversion and alloying reactions, has been regarded as an ideal candidate anode material for sodium-ion batteries. However, the severe volume expansion, sluggish kinetics, and polyselenide shuttle of the Sb₂Se₃-based anode lead to serious pulverization at high current density, restricting its industrialization. Herein, a unique structure of Sb₂Se₃ nanowires uniformly anchored between Ti₃C₂T_x (MXene) nanosheets was prepared by the electrostatic self-assembly method. The MXene can impede the volume expansion of Sb₂Se₃ nanowires in the sodiation process. Moreover, the Sb₂Se₃ nanowires can reduce the restacking of Ti₃C₂T_x nanosheets and enhance electrolyte accessibility. Furthermore, density functional theory calculations confirm the increased reaction kinetics and better sodium storage capability through the composite of Ti₃C₂T_x with Sb₂Se₃ and the high adsorption capability of Ti₃C₂T_x to polyselenides. Therefore, the resultant Sb₂Se₃/Ti₃C₂T_x anodes show high rate capability (369.4 mAh/g at 5 A/g) and cycling performance (568.9 and 304.1 mAh/g at 0.1 A/g after 100 cycles and at 1.0 A/g after 500 cycles). More importantly, the full sodium-ion batteries using the Sb₂Se₃/Ti₃C₂T_x anode and Na₃V₂(PO₄)₃/carbon cathode exhibit high energy/power densities and outstanding cycle performance.

Synergistically Achieving Superior Sodium Storage of Metal Selenides by Constructing N-Doped Carbon Foams and Utilizing Cu-Driven Replacement Reaction

Metal selenides are considered as one of the most promising anode materials for Na-ion batteries owing to high specific capacity and relatively higher electronic conductivity compared with metal sulfides or oxides. However, such anodes still suffer from huge volume change upon repeated Na⁺ insertion/extraction processes and simultaneously undergo severe shuttle effect of polyselenides, thus leading to poor electrochemical performance. Herein, a facile chemical-blowing and selenization strategy to fabricate 3D interconnected hybrids built from metal selenides (MSe, M = Mn, Co, Cr, Fe, In, Ni, Zn) nanoparticles encapsulated in in situ formed N-doped carbon foams (NCFs) is reported. Such hybrids not only provide ultrasmall active nanobuilding blocks (≈15 nm), but also efficiently anchor them inside the conductive NCFs, thus enabling both high-efficiency utilization of active components and high structural stability. On the other hand, Cu-driven replacement reaction is utilized for efficiently inhibiting the shuttle effect of polyselenides in ether-based electrolyte. Benefiting from the combined merits of the unique MSe@NCFs and the utilization of the conversion of metal selenides to copper selenides, the as-obtained hybrids (MnSe as an example) exhibit superior rate capability (386.6 mAh g^-1 up to 8 A g^-1 ) and excellent cycling stability (347.7 mAh g^-1 at 4.0 A g^-1 after 1200 cycles).

Ga2Te3-Based Composite Anodes for High-Performance Sodium-Ion Batteries

Recently, metal chalcogenides have received considerable attention as prospective anode materials for sodium-ion batteries (SIBs) because of their high theoretical capacities based on their alloying or conversion reactions. Herein, we demonstrate a gallium(III) telluride (Ga₂Te₃)-based ternary composite (Ga₂Te₃-TiO₂-C) synthesized via a simple high-energy ball mill as a great candidate SIB anode material for the first time. The electrochemical performance, as well as the phase transition mechanism of Ga₂Te₃ during sodiation/desodiation, is investigated. Furthermore, the effect of C content on the performance of Ga₂Te₃-TiO₂-C is studied using various electrochemical analyses. As a result, Ga₂Te₃-TiO₂-C with an optimum carbon content of 10% (Ga₂Te₃-TiO₂-C(10%)) exhibited a specific capacity of 437 mAh·g^-1 after 300 cycles at 100 mA·g^-1 and a high-rate capability (capacity retention of 96% at 10 A·g^-1 relative to 0.1 A·g^-1). The good electrochemical properties of Ga₂Te₃-TiO₂-C(10%) benefited from the presence of the TiO₂-C hybrid buffering matrix, which improved the mechanical integrity and electrical conductivity of the electrode. This research opens a new direction for the improvement of high-performance advanced SIB anodes with a simple synthesis process.

Recent Advancements in Chalcogenides for Electrochemical Energy Storage Applications

Energy storage has become increasingly important as a study area in recent decades. A growing number of academics are focusing their attention on developing and researching innovative materials for use in energy storage systems to promote sustainable development goals. This is due to the finite supply of traditional energy sources, such as oil, coal, and natural gas, and escalating regional tensions. Because of these issues, sustainable renewable energy sources have been touted as an alternative to nonrenewable fuels. Deployment of renewable energy sources requires efficient and reliable energy storage devices due to their intermittent nature. High-performance electrochemical energy storage technologies with high power and energy densities are heralded to be the next-generation storage devices. Transition metal chalcogenides (TMCs) have sparked interest among electrode materials because of their intriguing electrochemical properties. Researchers have revealed a variety of modifications to improve their electrochemical performance in energy storage. However, a stronger link between the type of change and the resulting electrochemical performance is still desired. This review examines the synthesis of chalcogenides for electrochemical energy storage devices, their limitations, and the importance of the modification method, followed by a detailed discussion of several modification procedures and how they have helped to improve their electrochemical performance. We also discussed chalcogenides and their composites in batteries and supercapacitors applications. Furthermore, this review discusses the subject’s current challenges as well as potential future opportunities.

Regulating the Interlayer Spacings of Hard Carbon Nanofibers Enables Enhanced Pore Filling Sodium Storage

Hard carbon (HC) represents an attractive anode material for sodium-ion batteries. However, most HC materials deliver limited capacity and the sodium storage mechanisms in the slope and plateau regions are controversial. Herein, a series of hard carbon nanofibers (HCNFs) with tunable interlayer spacings are designed to understand the sodium storage manners in HC. The optimized HCNFs featuring short-range graphitic layers with sufficient interlayer spacings (0.37-0.40 nm) for Na⁺ intercalation deliver a high reversible capacity (388 mAh g^-1 at 30 mA g^-1 ) and good rate capability. In-situ X-ray diffraction and Raman characterizations reveal a revised adsorption/insertion-filling sodium storage mechanism. Combined with the density functional theory (DFT) calculation, the detailed relationship between pore-filling plateau capacity and interlayer spacing is disclosed. It is found that sufficient interlayer spacings (>0.37 nm) provide diffusion channels for Na⁺ to reach the pores for further filling. Additionally, the reason for plateau-region capacity degradation of the HCNFs is completely demonstrated. This contribution provides insights into the sodium storage mechanism and rational construction of high-performance HC anode materials.

Engineering Nanostructured Antimony-Based Anode Materials for Sodium Ion Batteries

Sodium-ion batteries (SIBs) are considered a potential alternative to lithium-ion batteries (LIBs) for energy storage due to their low cost and the large abundance of sodium resources. The search for new anode materials for SIBs has become a vital approach to satisfying the ever-growing demands for better performance with higher energy/power densities, improved safety and a longer cycle life. Recently, antimony (Sb) has been extensively researched as a promising candidate due to its high specific capacity through an alloying/dealloying process. In this review article, we will focus on different categories of the emerging Sb based anode materials with distinct sodium storage mechanisms including Sb, two-dimensional antimonene and antimony chalcogenide (Sb2S3 and Sb2Se3). For each part, we emphasize that the novel construction of an advanced nanostructured anode with unique structures could effectively improve sodium storage properties. We also highlight that sodium storage capability can be enhanced through designing advanced nanocomposite materials containing Sb based materials and other carbonaceous modification or metal supports. Moreover, the recent advances in operando/in-situ investigation of its sodium storage mechanism are also summarized. By providing such a systematic probe, we aim to stress the significance of novel nanostructures and advanced compositing that would contribute to enhanced sodium storage performance, thus making Sb based materials as promising anodes for next-generation high-performance SIBs.

A TiSe2 -Graphite Dual Ion Battery: Fast Na-Ion Insertion and Excellent Stability

The sodium dual ion battery (Na-DIB) technology is proposed as highly promising alternative over lithium-ion batteries for the stationary electrochemical energy-storage devices. However, the sluggish reaction kinetics of anode materials seriously impedes their practical implementation. Herein, a Na-DIB based on TiSe₂ -graphite is reported. The high diffusion coefficient of Na-ions (3.21×10^-11 -1.20×10^-9  cm²  s^-1 ) and the very low Na-ion diffusion barrier (0.50 eV) lead to very fast electrode kinetics, alike in conventional surface capacitive storage systems. In-situ investigations reveal that the fast Na-ion diffusion involves four insertion stage compositions. A prototype cell shows a reversible capacity of 81.8 mAh g^-1 at current density of 100 mA g^-1 , excellent stability with 83.52 % capacity retention over 200 cycles and excellent rate performance, suggesting its potential for next-generation large scale high-performance stationary energy storage systems.

Close-spaced thermally evaporated 3D Sb2Se3 film for high-rate and high-capacity lithium-ion storage

As a key factor for fast-charging lithium-ion batteries (LIBs), high-rate anode materials that can recharge in a few minutes have aroused increasing attention. However, high-rate performance is always accompanied by low theoretical capacities, such as the widely known high-rate electrode of Li4Ti5O12 (175 mA h g-1), which severely limits its large-scale implementation in the development of high power density LIBs. Here, we report a modified close-spaced thermal evaporation process to deposit 3D-structured Sb2Se3 films (3D-SSF) with tunable morphology as an additive-free anode for LIBs. After a high-rate activation process, 3D-SSF exhibits a flatter discharge plateau than the reported results and could deliver a high capacity of 471 mA h g-1 at an ultrahigh current density of 21 440 mA g-1, which is superior to the widely known high-rate Li4Ti5O12 anode (over 150 mA h g-1 at 8750 mA g-1). Moreover, we reveal a current-regulated Li-ion storage mechanism where 3D-SFF undergoes a synergistic conversion and alloying reaction at low current densities, while an alloying reaction-dominated process at high rates. Beyond that, full batteries with excellent rate performance were successfully assembled by pairing with homemade LiFePO4 (LFP) as the cathode.

An overview of the current status and prospects of cathode materials based on transition metal sulfides for magnesium-ion batteries

TMSs as cathode materials used in MIBs.

Boosting Potassium Storage by Integration Advantageous of Defect Engineering and Spatial Confinement: A Case Study of Sb2 Se3

The potassium ion batteries (KIBs) based on conversion/alloying reaction mechanisms show high theoretical capacity. However, their applications are hampered by the poor cyclability resulting from the inherent large volume variations and the sluggish kinetics during K⁺ repeated insertion/extraction process. Herein, taken Sb₂ Se₃ as a model material, by rational design, nickel doped-carbon coated Sb₂ Se₃ nanorods (denoted as (Sb_0.99 Ni_0.01 )₂ Se₃ @C) are prepared through combined strategies of the conductive encapsulation and crystal structure modification. The carbon coating acts as an efficient buffer layer that maintains superior structural stability upon cycling. The introduction of Ni atoms can enhance electrical conductivity, leading to outstanding rate performance, which are confirmed by density functional theory calculation. The (Sb_0.99 Ni_0.01 )₂ Se₃ @C displays excellent reversible capacity (410 mAh g^-1 at 0.1 A g^-1 after 100 cycles) and unprecedented rate capability (140 mAh g^-1 at 10 A g^-1 ). Furthermore, KFeHCF//(Sb_0.99 Ni_0.01 )₂ Se₃ @C full cell exhibits a high specific capacity (408 mAh g^-1 at 0.1 A g^-1 ), superior rate capability (260 mAh g^-1 at 2 A g^-1 ). This work can open up a new avenue for the design of stable conversion/alloying-based anodes for high energy density KIBs.

Ultra-stable Sb confined into N-doped carbon fibers anodes for high-performance potassium-ion batteries

Antimony-based materials with high theoretical capacity are known as promising anodes for potassium-ion batteries (PIBs). However, they still face challenges from the large ionic radius of the K ion, which has sluggish kinetics. Much effort is needed to exploit high-performance electrode materials to satisfy the reversible capacity of PIBs. In this paper, nano Sb confined in N-doped carbon fibers (Sb@CN nanofibers) were successfully prepared through an electrospinning method, which was designed to improve potassium storage performances. Sb@CN nanofibers benefit from the fact that the synergy between the porous nanofiber frame structure and the uniformly distributed Sb nano-components in the carbon matrix can effectively accelerate the ion migration rate and reduce the mechanical stress caused by K⁺ insertion/extraction, Sb@CN nanofiber electrodes thus exhibited excellent potassium storage performance, especially long cycle stability, as expected. When utilized as a PIB anode, they delivered high reversible capacity of 360.2 mAh g^-1 after 200 cycles at 50 mA g^-1, and a particularly stable capacity of 212.7 mAh g^-1 was also obtained after 1000 cycles even at 5000 mA g^-1. Given such outstanding electrochemical performances, this work is expected to provide insight into the development and exploration of advanced alloy-type electrodes for PIBs.

High Na+ Mobility in rGO Wrapped High Aspect Ratio 1D SbSe Nano Structure Renders Better Electrochemical Na+ Battery Performance

We chose to understand the cyclic instability and rate instability issues in the promising class of Na⁺ conversion and alloying anodes with Sb₂ Se₃ as a typical example. We employ a synthetic strategy that ensures efficient rGO (reduced graphene oxide) wrapping over Sb₂ Se₃ material. By utilization of the minimum weight of additive (5 wt.% of rGO), we achieved a commendable performance with a reversible capacity of 550 mAh g^-1 at a specific current of 100 mA g^-1 and an impressive rate performance with 100 % capacity retention after high current cycling involving a 2 Ag^-1 intermediate current step. The electrochemical galvanostatic intermittent titration technique (GITT) has been employed for the first time to draw a rationale between the enhanced performance and the increased mobility in the rGO wrapped composite (Sb₂ Se₃ -rGO) compared to bare Sb₂ Se₃ . GITT analysis reveals higher Na⁺ diffusion coefficients (approx. 30 fold higher) in the case of Sb₂ Se₃ -rGO as compared to bare Sb₂ Se₃ throughout the operating voltage window. For Sb₂ Se₃ -rGO the diffusion coefficients in the range of 8.0×10^-15  cm²  s^-1 to 2.2×10^-12  cm²  s^-1 were observed, while in case of bare Sb₂ Se₃ the diffusion coefficients in the range of 1.6×10^-15  cm²  s^-1 to 9.4×10^-15  cm²  s^-1 were observed.

Comparison of Clusters Produced from Sb2Se3 Homemade Polycrystalline Material, Thin Films, and Commercial Polycrystalline Bulk Using Laser Desorption Ionization with Time of Flight Quadrupole Ion Trap Mass Spectrometry

This study compared Sb₂Se₃ material in the form of commercial polycrystalline bulk, sputtered thin film, and homemade polycrystalline material using laser desorption ionization (LDI) time of flight mass spectrometry with quadrupole ion trap mass spectrometry. It also analyzed the stoichiometry of the Sb_mSe_n clusters formed. The results showed that homemade Sb₂Se₃ bulk was more stable compared to thin film; its mass spectra showed the expected cluster formation. The use of materials for surface-assisted LDI (SALDI), i.e., graphene, graphene oxide, and C₆₀, significantly increased the mass spectra intensity. In total, 19 Sb_mSe_n clusters were observed. Six novel, high-mass clusters-Sb₄Se₄⁺, Sb₅Se_3-6⁺, and Sb₇Se₄⁺-were observed for the first time when using paraffin as a protective agent.

Composition Engineering Boosts Voltage Windows for Advanced Sodium-Ion Batteries

Transition-metal selenides have captured sustainable research attention in energy storage and conversion field as promising anodes for sodium-ion batteries. However, for the majority of transition metal selenides, the potential windows have to compress to 0.5-3.0 V for the maintenance of cycling and rate capability, which largely sacrifices the capacity under low voltage and impair energy density for sodium full batteries. Herein, through introducing diverse metal ions, transition-metal selenides consisted of different composition doping (CoM-Se₂@NC, M = Ni, Cu, Zn) are prepared with more stable structures and higher conductivity, which exhibit superior cycling and rate properties than those of CoSe₂@NC even at a wider voltage range for sodium ion batteries. In particular, Zn²⁺ doping demonstrates the most prominent sodium storage performance among series materials, delivering a high capacity of 474 mAh g^-1 after 80 cycles at 500 mA g^-1 and rate capacities of 511.4, 382.7, 372.1, 339.2, 306.8, and 291.4 mAh g^-1 at current densities of 0.1, 0.5, 1.0, 1.4, 1.8, and 2.0 A g^-1, respectively. The composition adjusting strategy based on metal ions doping can optimize electrochemical performances of metal selenides, offer an avenue to expand stable voltage windows, and provide a feasible approach for the construction of high specific energy sodium-ion batteries.

High-Safety Symmetric Sodium-Ion Batteries Based on Nonflammable Phosphate Electrolyte and Double Na3V2(PO4)3 Electrodes

Sodium-ion batteries (SIBs) have been viewed as a promising candidate for grid-scale energy storage systems owing to their low cost and abundant Na resources. However, insufficient safety and poor cycling performance of current SIBs are hampering their implementation. Herein, we develop a symmetric SIB by employing Na₃V₂(PO₄)₃ as both cathode and anode along with the nonflammable triethyl phosphate dissolving 0.9 M NaClO₄ as the electrolyte. The symmetric SIB demonstrates a superior rate capability (35.1 mA h g^-1 at 32 C) and excellent cycling performance with a capacity retention of 88.9% after 500 cycles at 2 C. This work demonstrates a new avenue to construct safe and long-cycle-life SIBs with a simple electrode manufacturing process.

General Approach to Produce Nanostructured Binary Transition Metal Selenides as High-Performance Sodium Ion Battery Anodes

Multiple transition metals containing chalcogenides have recently drawn boosted attraction as anodes for sodium ion batteries (SIBs). Their greatly enhanced electrochemical performances can be attributed to the superior intrinsic conductivities and richer redox reactions, comparative to mono metal chalcogenides. To employ various binary metals comprising selenides (B-TMSs) for SIBs, discovery of a simplistic, scalable and universal synthesis approach is highly desirable. Herein, a simple, facile, and comprehensive strategy to produce various combinations of nanostructured B-TMSs is presented. As a proof of concept, optimized, high surface area bearing, and hierarchical nanosheets of iron-nickel selenide (FNSe), iron-cobalt selenide, and nickel-cobalt selenide are produced and employed in SIBs. These B-TMSs exhibit adequately high energy capacities, excellent rate capabilities, and an extraordinarily stable life of 2600 cycles. As far as it is known, it is the first work to discuss sodium storage of FNSe, so various in situ and ex situ battery analyses are carried out to probe the sodium storage mechanism. When employed in sodium full batteries, these B-TMSs present reasonably high reversible specific capacities even after 100 cycles. Overall, the presented strategy will pave the way for facile synthesis of numerous binary transition metal chalcogenides that are the potential materials for energy storage and conversion systems.

Carbon-Based Alloy-Type Composite Anode Materials toward Sodium-Ion Batteries

In the scenario of renewable clean energy gradually replacing fossil energy, grid-scale energy storage systems are urgently necessary, where Na-ion batteries (SIBs) could supply crucial support, due to abundant Na raw materials and a similar electrochemical mechanism to Li-ion batteries. The limited energy density is one of the major challenges hindering the commercialization of SIBs. Alloy-type anodes with high theoretical capacities provide good opportunities to address this issue. However, these anodes suffer from the large volume expansion and inferior conductivity, which induce rapid capacity fading, poor rate properties, and safety issues. Carbon-based alloy-type composites (CAC) have been extensively applied in the effective construction of anodes that improved electrochemical performance, as the carbon component could alleviate the volume change and increase the conductivity. Here, state-of-the-art CAC anode materials applied in SIBs are summarized, including their design principle, characterization, and electrochemical performance. The corresponding alloying mechanism along with its advantages and disadvantages is briefly presented. The crucial roles and working mechanism of the carbon matrix in CAC anodes are discussed in depth. Lastly, the existing challenges and the perspectives are proposed. Such an understanding critically paves the way for tailoring and designing suitable alloy-type anodes toward practical applications.

Exploring the sodium ion storage mechanism of gallium sulfide (Ga2S3): a combined experimental and theoretical approach

Developing sodium ion battery (SIB) anode materials of a low-cost and high-capacity nature for future large-scale applications still involves challenges. Herein, we have reported gallium sulfide (Ga2S3) as a novel SIB anode material for the first time. Ga2S3 nanorods have been synthesized via the facile hydrothermal preparation of a GaOOH precursor with subsequent H2S annealing. Mixed with graphene upon electrode preparation, this Ga2S3 electrode maintains a reversible specific capacity of 476 mA h g-1 after 100 cycles at a current density of 0.4 A g-1, with a coulombic efficiency of over 99%. Ex situ XRD analysis and theoretical calculations are employed to comprehensively elucidate the detailed sodium ion storage mechanism of Ga2S3, which is composed of initial Na+ intercalation, a subsequent multi-step conversion reaction between S and Na+, and an eventual alloying reaction between Ga and Na+ with the end product of Na7Ga13. Further kinetics analysis has demonstrated that the conversion reaction is the rate-limiting step due to a multi-step reaction with the intermediate phase of GaS. Moreover, the appearance of liquid metal Ga, as confirmed via TEM observations and theoretical calculations, can serve as a self-healing agent that repairs cracks in the electrode. Our findings shed light on the further design of Ga-based materials, and they also can be extended to solid-state-battery systems.

Natural stibnite ore (Sb2S3) embedded in sulfur-doped carbon sheets: enhanced electrochemical properties as anode for sodium ions storage

Antimony sulfide (Sb₂S₃) has drawn widespread attention as an ideal candidate anode material for sodium-ion batteries (SIBs) due to its high specific capacity of 946 mA h g⁻¹ in conversion and alloy reactions. Nevertheless, volume expansion, a common flaw for conversion-alloy type materials during the sodiation and desodiation processes, is bad for the structure of materials and thus obstructs the application of antimony sulfide in energy storage. A common approach to solve this problem is by introducing carbon or other matrices as buffer material. However, the common preparation of Sb₂S₃ could result in environmental pollution and excessive energy consumption in most cases. To incorporate green chemistry, natural stibnite ore (Sb₂S₃) after modification via carbon sheets was applied as a first-hand material in SIBs through a facile and efficient strategy. The unique composites exhibited an outstanding electrochemical performance with a higher reversible capacity, a better rate capability, as well as an excellent cycling stability compared to that of the natural stibnite ore. In short, the study is expected to offer a new approach to improve Sb₂S₃ composites as an anode in SIBs and a reference for the development of natural ore as a first-hand material in energy storage.

Antimony sulfide (Sb₂S₃) has drawn widespread attention as an ideal candidate anode material for sodium-ion batteries (SIBs) due to its high specific capacity of 946 mA h g⁻¹ in conversion and alloy reactions.

Facile synthesis and electrochemical Mg-storage performance of Sb2Se3 nanowires and Bi2Se3 nanosheets

Sb₂Se₃ nanowires and Bi₂Se₃ nanosheets are investigated as conversion-type cathodes for rechargeable Mg batteries.

Construction of Sb2Se3 nanocrystals on Cu2−xSe@C nanosheets for high performance lithium storage

Cu_2−xSe@C@Sb₂Se₃ with enhanced electrochemical performance was designed and fabricated, where Sb₂Se₃ nanoparticles were anchored on Cu_2−xSe@C nanosheets.

Molecular-Level CuS@S Hybrid Nanosheets Constructed by Mineral Chemistry for Energy Storage Systems

The transition-metal sulfide, CuS, is deemed a promising material for energy storage, mainly derived from its good chemisorption and conductivity, although serious capacity fading limits its advancement within reversible lithium storage. Learning from the gold extraction method utilizing the lime-sulfur-synthetic-solution, a CuS@S hybrid utilizing CaS _x as both sulfur resource and reductant-oxidant is prepared, which is an efficient approach to apply the metallurgy for the preparation of electrode materials. Regulating the amount of CuCl₂, the CuS@S is induced to reach a molecular-level hybrid. When utilized as an anode within a lithium-ion battery, it presents the specific capacity of 514.4 mA h g^-1 at 0.1 A g^-1 over 200 cycles. Supported by the analyses of pseudo-capacitive behaviors, it is confirmed that the CuS matrix with the suitable content of auxiliary sulfur could improve the durability of the CuS-based anode. Expanding the wider application within lithium-sulfur batteries, the synchronous growth of CuS@S exhibits stronger chemisorption with polysulfides than the mechanical mixture of CuS and S. A suite of in situ electrochemical impedance spectroscopy studies further investigates the stable resistances of the CuS@S within the charge/discharge process, corresponding to the reversible structure evolution. This systematic work may provide a practical fabricating route of metal sulfides for scalable energy storage applications.

Constructing Three-Dimensional Porous Carbon Framework Embedded with FeSe2 Nanoparticles as an Anode Material for Rechargeable Batteries

Metal selenides have caused widespread concern due to their high theoretical capacities and appropriate working potential; however, they suffer from large volume variation during cycling and low electrical conductivity, which limit their practical applications. In this article, a three-dimensional (3D) porous carbon framework embedded with homogeneous FeSe₂ nanoparticles (3D porous FeSe₂/C composite) was synthesized by a facile calcined approach, following a selenized method without a template. As the uniformity of FeSe₂ nanoparticles and 3D porous structure are beneficial to accommodate volume stress upon cycling and shorten electrons/ions transport path, associated with carbon as a buffer matrix for increasing conductivity, the 3D porous FeSe₂/C composite displays excellent electrochemical properties with high reversible capacities of 798.4 and 455.0 mA h g^-1 for lithium-ion batteries and sodium-ion batteries, respectively, when the current density is 100 mA g^-1 after 100 cycles. In addition, the as-prepared composite exhibits good cycling stability as compared to bare FeSe₂ nanoparticles. Therefore, the facile synthetic strategy in the current work provides a new perspective in constructing a high-performance anode.

Polycrystalline and Mesoporous 3-D Bi2O3 Nanostructured Negatrodes for High-Energy and Power-Asymmetric Supercapacitors: Superfast Room-Temperature Direct Wet Chemical Growth

Superfast (≤10 min) room-temperature (300 K) chemical synthesis of three-dimensional (3-D) polycrystalline and mesoporous bismuth(III) oxide (Bi₂O₃) nanostructured negatrode (as an abbreviation of negative electrode) materials, viz., coconut shell, marigold, honey nest cross section and rose with different surface areas, charge transfer resistances, and electrochemical performances essential for energy storage, harvesting, and even catalysis devices, are directly grown onto Ni foam without and with poly(ethylene glycol), ethylene glycol, and ammonium fluoride surfactants, respectively. Smaller diffusion lengths, caused by the involvement of irregular crevices, allow electrolyte ions to infiltrate deeply, increasing the utility of inner active sites for the following electrochemical performance. A marigold 3-D Bi₂O₃ electrode of 58 m²·g^-1 surface area has demonstrated a specific capacitance of 447 F·g^-1 at 2 A·g^-1 and chemical stability of 85% even after 5000 redox cycles at 10 A·g^-1 in a 6 M KOH electrolyte solution, which were higher than those of other morphology negatrode materials. An asymmetric supercapacitor (AS) device assembled with marigold Bi₂O₃ negatrode and manganese(II) carbonate quantum dots/nickel hydrogen-manganese(II)-carbonate (MnCO₃QDs/NiH-Mn-CO₃) positrode corroborates as high as 51 Wh·kg^-1 energy at 1500 W·kg^-1 power and nearly 81% cycling stability even after 5000 cycles. The obtained results were comparable or superior to the values reported previously for other Bi₂O₃ morphologies. This AS assembly glowed a red-light-emitting diode for 20 min, demonstrating the scientific and industrial credentials of the developed superfast Bi₂O₃ nanostructured negatrodes in assembling various energy storage devices.

Electrochemical Investigation of Natural Ore Molybdenite (MoS2) as a First-Hand Anode for Lithium Storages

Considering serious pollution from the traditional chemical synthesis process, the resource-rich, clean, and first-hand electrode materials are greatly desired. Natural ore molybdenite (MoS₂), as the low-cost, high-yield, and environmental-friendly natural source, is investigated as a first-hand anode material for lithium-ion batteries (LIBs). Compared with chemosynthetic pure MoS₂, natural molybdenite provides an ordered ion diffusion channel more effectively owing to its excellent characteristics, containing well-crystalline, large lattice distance, and trance dopants. Even at a large current density of 2.0 A g^-1, a natural molybdenite electrode employing a carboxymethyl cellulose binder displays an initial charge capacity of 1199 mA h g^-1 with a capacity retention of 72% after 1000 cycles, much higher than those of the electrodes utilizing a poly(vinylidene fluoride) binder. These types of binders play a crucial role in stabilizing a microstructure demonstrated by ex situ scanning electron microscopy and in affecting pseudocapacitive contributions quantitatively determined by a series of kinetic exploration. Briefly, this work might open up a new avenue toward the use of natural molybdenite as a first-hand LIB anode in scalable applications and deepen our understanding on the fundamental effect of binders in the metal-sulfide.

Influence of Na and Nb co-substitution on electrochemical performance of ternary cathode materials for Li-ion batteries

In the present study, Li_1−xNa_x(Ni_0.6Co_0.2Mn_0.2−yNb_y)O₂, a novel layered cathodic compound, is synthesized using an economically feasible polymer pyrolysis method.

Assembly of Na3V2(PO4)2F3@C nanoparticles in reduced graphene oxide enabling superior Na+ storage for symmetric sodium batteries

Symmetrical full cell of NVPF@C@rGO as both cathode and anode could light the LED lamp successfully after the 25th charge–discharge cycle at 1C.

Interlayer-Expanded Metal Sulfides on Graphene Triggered by a Molecularly Self-Promoting Process for Enhanced Lithium Ion Storage

A general synthetic approach has been demonstrated to fabricate three-dimensional (3D) structured metal sulfides@graphene, employing few-layered sulfide nanostructures with expanded interlayer spacing of the (002) plane (e.g., 0.98 nm for MoS₂ nanoclusters and 0.65 nm for VS₄ nanoribbons) and electrically conductive graphene as ideal building blocks. Here, small molecules (thioacetamide) acting as both the sulfur source and, more importantly, the structure-directing agent adjusting the interlayer spacing are wisely selected, further contributing to a sufficient space for ultrafast Li⁺ ion intercalation. The appealing features of a mechanically robust backbone, ultrathin thickness, abundant exposure of interlayer edges, and good electrical conductivity in such 3D architectures are favorable for providing easy access for the electrolyte to the structures and offering a shortened diffusion length of Li⁺ when utilized for energy storage. As a proof of concept, the electrochemical behavior of the resulting 3D structured metal sulfides@graphene as an anode material of lithium ion batteries (LIBs) is systematically investigated. As a consequence, high specific capacities, long lifespans, and superior rate capabilities have been realized in such well-designed architectures, e.g. maintaining a specific capacity as high as 965 mAh g^-1 for 120 cycles for VS₄@graphene and 1100 mAh g^-1 for 150 cycles for MoS₂@graphene.