Antimony Nanoparticles Encapsulated in Self-Supported Organic Carbon with a Polymer Network for High-Performance Lithium-Ion Batteries Anode

Antimony (Sb) demonstrates ascendant reactive activation with lithium ions thanks to its distinctive puckered layer structure. Compared with graphite, Sb can reach a considerable theoretical specific capacity of 660 mAh g-1 by constituting Li3Sb safer reaction potential. Hereupon, with a self-supported organic carbon as a three-dimensional polymer network structure, Sb/carbon (3DPNS-Sb/C) composites were produced through a hydrothermal reaction channel followed by a heat disposal operation. The unique structure shows uniformitarian Sb nanoparticles wrapped in a self-supported organic carbon, alleviating the volume extension of innermost Sb alloying, and conducive to the integrality of the construction. When used as anodes for lithium-ion batteries (LIBs), 3DPNS-Sb/C exhibits a high invertible specific capacity of 511.5 mAh g-1 at a current density of 0.5 A g-1 after 100 cycles and a remarkable rate property of 289.5 mAh g-1 at a current density of 10 A g-1. As anodes, LIBs demonstrate exceptional electrochemical performance.

Heterogeneous Interface Design for Enhanced Sodium Storage: Sb Quantum Dots Confined by Functional Carbon

Antimony (Sb) is considered a promising anode material for sodium-ion batteries due to its high specific capacity and moderate working potential. However, the non-negligible volume variation leads to the rapid decay of capacity, which hinders the practical application of Sb anode materials. Here, an economical and scalable route with high yield is proposed to obtain Sb ultrafine nanocrystals embedded in a porous carbon skeleton. Notably, the synergetic effect of the heterogeneous structure is maximized by inducing the interfacial coupling SbOC and creating buffering space for the volume effect of Sb. The high-entropy phase interface creates the doping site breaking the periodicity of atoms and alters the electronic structure, also bridging the slip of intergranular defects. Thus, the electronic conductivity and phase interface structural stability are reinforced. The mechanism of accelerating electron migration at the heterogeneous phase interface is visualized through the density functional theory method, and the mass/charge-transfer kinetics is analyzed via the calculation of surface-induced capacitive contribution.

Impact of CO2 activation on the structure, composition, and performance of Sb/C nanohybrid lithium/sodium-ion battery anodes

Antimony (Sb) has been regarded as one of the most promising anode materials for both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) and attracted much attention in recent years. Alleviating the volumetric effect of Sb during charge and discharge processes is the key point to promote Sb-based anodes to practical applications. Carbon dioxide (CO2) activation is applied to improve the rate performance of the Sb/C nanohybrid anodes caused by the limited diffusion of Li/Na ions in excessive carbon components. Based on the reaction between CO2 and carbon, CO2 activation can not only reduce the excess carbon content of the Sb/C nanohybrid but also create abundant mesopores inside the carbon matrix, leading to enhanced rate performance. Additionally, CO2 activation is also a fast and facile method, which is perfectly suitable for the fabrication system we proposed. As a result, after CO2 activation, the average capacity of the Sb/C nanohybrid LIB anode is increased by about 18 times (from 9 mA h g-1 to 160 mA h g-1) at a current density of 3300 mA g-1. Moreover, the application of the CO2-activated Sb/C nanohybrid as a SIB anode is also demonstrated, showing good electrochemical performance.

Core@shell Sb@Sb2O3 nanoparticles anchored on 3D nitrogen-doped carbon nanosheets as advanced anode materials for Li-ion batteries

Antimony (Sb) based materials are regarded as promising anode materials for Li-ion batteries (LIBs) because of the high capacity, appropriate working potential, and earth abundance of antimony. However, the quick capacity decay due to the huge volume expansion during the cycling process seriously hinders its practical applications. Here, a nanocomposite of core@shell Sb@Sb₂O₃ particles anchored on 3D porous nitrogen-doped carbon (3DNC) nanosheets is synthesized by freeze drying and sintering in a reducing atmosphere. Structural characterization shows that the developed Sb@Sb₂O₃/3DNC electrode has a high surface area (839.8 m² g^-1) and unique Sb-O-C bonding, both contributing to the excellent electrochemical performance. The initial charge and discharge specific capacities of the Sb@ Sb₂O₃/3DNC anode in LIB tests are 1109 mA h g^-1 and 1810 mA h g^-1, respectively. Also, it shows a charge capacity of 696.9 mA h g^-1 after 500 cycles at 1 A g^-1 and 458 mA h g^-1 at a current density of 5 A g^-1. Moreover, the assembled Sb@Sb₂O₃/3DNC‖LiNi_0.6Co_0.2Mn_0.2O₂ battery exhibits a discharge capacity of more than 100 mA h g^-1 after 25 cycles at 100 mA g^-1. The synthetic method can be extended to obtain other nanocomposites of metal and carbon materials for high-performance energy storage devices.

Continuous preparation of antimony nanocrystals with near infrared photothermal property by pulsed laser ablation in liquids

Antimony nanocrystals (Sb NCs) are of interest in energy storage, catalysis and cancer therapy for its special physical, chemical and biomedical properties. However, methodology challenges still remain in preparation of colloidal Sb NCs, due to the restricted reaction solution systems, high temperature and time costing for common routes. Herein, size controllable colloidal Sb NCs were continuously prepared by pulsed laser ablation of Sb target in different solvents, owning to the metal nanodroplet explosive ejection and thermal evaporation mechanisms. These well dispersed and stable Sb NCs showed excellent photothermal property in the near-infrared-II window.

Ultrafine antimony (Sb) nanoparticles encapsulated into a carbon microfiber framework as an excellent LIB anode with a superlong life of more than 5000 cycles

Antimony (Sb) anode has attracted increasing attention given its high theoretical capacity and suitable working potential. Nonetheless, its practical application is largely hindered by huge volume changes during the cyclic process, resulting in unsatisfactory long-term cycled stabilities at high current density. In this work, large-scale ultrafine Sb nanoparticles are functionally designed to encapsulate into a 3D carbon microfiber framework (CMF) via a scalable electrospinning approach followed by a thermal treatment process. This fabrication strategy effectively avoids the change in the volume of the Sb anode and provides a fast conductive network to serve as an efficient 3D e/Li⁺ transport pathway. Benefiting from this novel structural design, an ultrafine Sb nanoparticles@carbon microfiber framework (U-Sb-NPs@CMF) composite anode used for lithium-ion batteries (LIBs) delivers a high reversible capacity of 622 mAh g^-1 after 200 cycles at 0.5 A g^-1 and 507 mAh g^-1 after 2000 cycles at 2 Ag^-1 and a high-capacity retention of 350 mAh g^-1 even after 5000 long-term cycles. These outstanding charge-discharge performances suggest that the U-Sb-NPs@CMF composite is a promising candidate for an anode material in the application of LIBs.

Porous Sb with three-dimensional Sb nanodendrites as electrode material for high-performance Li/Na-ion batteries

The increasing demand in energy consumption and the use of clean energy from sustainable energy sources have driven the research in the development of advanced materials for Li-ion and Na-ion batteries. In this work, we have developed a simple technique to synthesize a porous Sb structure through a galvanic replacement reaction between Sb³⁺ and Zn particles. The porous Sb structure consists of a three-dimensional-hierarchical structure with tree-like nanoscale Sb dendrites. The Sb in the nanodendrites is crystal of a rhombohedral structure. We construct Li-/Na-ion half cells and Li-/Na-ion full cells with the Sb nanodendrites as the active material in the working electrode and anode, respectively, and introduce an additive of vinylene carbonate for the Li-ion half/full cells and an additive of fluoroethylene carbonate for the Na-ion half/full cells. All the Li-/Na-ion half cells and Li-/Na-ion full cells exhibit excellent electrochemical performance and cycling stability. Such excellent performance can be attributed to the synergistic interaction between the three-dimensional-dendritic structure and electrolyte, which likely ensures fast transport of ions and electrons and the formation of a stable solid-state interphase.

Microsized Antimony as a Stable Anode in Fluoroethylene Carbonate Containing Electrolytes for Rechargeable Lithium-/Sodium-Ion Batteries

Metallic antimony (Sb) is an attractive anode material for lithium-/sodium-ion batteries (LIBs/SIBs) because of its high theoretical capacity (660 mA h g^-1), but it suffers from poor cycling performance caused by the huge volume expansion and the unstable solid electrolyte interphase (SEI). Here, we report a high-performing microsized Sb anode for both LIBs and SIBs by coupling it with fluoroethylene carbonate (FEC) containing electrolytes. The optimum amount of FEC (10 vol %) renders a stable LiF/NaF-rich SEI on Sb electrodes that can suppress the continuous electrolyte decomposition and accommodate the volume variation. The microsized Sb electrode gradually evolves into a porous integrity assembled by nanoparticles in FEC-containing electrolytes during cycling, which is totally different from that in the FEC-free counterpart. As a result, the microsized Sb electrodes exhibit a reversible capacity of 540 mA h g^-1 with 85.3% capacity retention after 150 cycles at 1000 mA g^-1 for LIBs and 605 mA h g^-1 with 95.4% capacity retention after 150 cycles at 200 mA g^-1 for SIBs. More impressively, the prototype full Li-based (i.e., Sb/LiNi_0.8Co_0.1Mn_0.1O₂ cell) and Na-based (i.e., Sb/Na₃V₂(PO₄)₂O₂F cell) batteries also achieve good cycling durability. This facile strategy of electrolyte formulation to boost the cycling performance of microsized Sb anodes will provide a new avenue for developing stable alloying-type materials for both LIBs and SIBs.

Mesoporous ZnCo2O4/rGO nanocomposites enhancing sodium storage

In this study, mesoporous ZnCo₂O₄/rGO nanocomposites were favorably synthesized via a simple solvothermal technique. As a prospective anode material for sodium-ion batteries, the resulting ZnCo₂O₄/rGO-II nanocomposite exhibited superior electrochemical sodium storage performance with predominant specific capacity, favorable cyclability and ascendant rate capability. For example, an outstanding discharge capacity of 210.5 mAh g^-1 was delivered at a current density of 200 mA g^-1. Notably, the nanocomposite could yield a discharge capacity of 101.7 mAh g^-1 at a current density of 1000 mA g^-1 after 500 loops, which certifies its superior capacity retention and predominant cycling stability. The boosted performance of the anode materials is due to the mutual synergistic effect resulting from a combination of the mesoporous ZnCo₂O₄ nanospheres and conducting reduced graphene oxide nanosheets.

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.

Advances in nanostructures fabricated via spray pyrolysis and their applications in energy storage and conversion

This review provides insight into various nanostructures designed by spray pyrolysis and their applications in energy storage and conversion.

Micron-Sized Nanoporous Antimony with Tunable Porosity for High-Performance Potassium-Ion Batteries

Potassium-ion batteries (KIBs) are considered favorable candidates for post-lithium-ion batteries, a quality attributed to their low cost, abundance as a resource, and high working potential (-2.93 V for K⁺/K). Owning to its relatively low potassiation potential and high theoretical capacity, antimony (Sb) is one of the most favorable anodes for KIBs. However, the large volume changes during K-Sb alloying and dealloying causes fast capacity degradation. In this report, nanoporous Sb (NP-Sb) is fabricated by an environmentally friendly vacuum-distillation method. The NP-Sb is formed via evaporating low-boiling-point zinc (Zn). The byproduct Zn can be recycled. It is further found that the morphology and porosity can be controlled by adjusting Zn-Sb composition and distillation temperature. The nanoporous structure can accommodate volume expansion and accelerate ion transport. The NP-Sb anode delivers an improved electrochemical performance. These results suggest that the vacuum-distillation method may provide a direction for the green, large-scale, and tunable fabrication of nanoporous materials.

A self-encapsulated porous Sb-C nanocomposite anode with excellent Na-ion storage performance

In this study, a self-encapsulated Sb-C nanocomposite as an anode material for sodium-ion batteries (SIBs) was successfully synthesised using an SbCl₃-citrate complex precursor, followed by a drying and calcination process under an inert N₂ atmosphere. When the molar ratio of SbCl₃ to citric acid was varied from 1 : 1 to 1 : 4, the Sb-C nanocomposite with a molar ratio of 1 : 3 (Sb-C3) exhibited the highest specific surface area (265.97 m² g^-1) and pore volume (0.158 cm³ g^-1). Furthermore, the Sb-C3 electrode showed a high reversible capacity of 559 mA h g^-1 at a rate of C/10 and maintained a high reversible capacity of 430 mA h g^-1 even after 195 cycles at a rate of 1C. The Sb-C3 electrode exhibited an excellent rate capability of 603, 445, and 357 mA h g^-1 at the rates of C/20, 5C, and 10C, respectively. Furthermore, a full cell composed of an Sb-C3 anode and a Na₃V₂(PO₄)₃ cathode exhibited good specific capacity and cyclability, making the Sb-C composite a promising anode material for high-performance SIBs.

Ultrasmall Sn nanoparticles embedded in spherical hollow carbon for enhanced lithium storage properties

Ultrasmall Sn nanoparticles (∼5 nm) homogeneously embedded in the shell of spherical hollow carbon show enhanced lithium storage properties with high capacity and a long life.

Bi2Se3/C Nanocomposite as a New Sodium-Ion Battery Anode Material

Bi₂Se₃ was studied as a novel sodium-ion battery anode material because of its high theoretical capacity and high intrinsic conductivity. Integrated with carbon, Bi₂Se₃/C composite shows excellent cyclic performance and rate capability. For instance, the Bi₂Se₃/C anode delivers an initial capacity of 527 mAh g^-1 at 0.1 A g^-1 and maintains 89% of this capacity over 100 cycles. The phase change and sodium storage mechanism are also carefully investigated.

The synthesis of FeCoS2 and an insight into its physicochemical performance

FeCoS₂ exhibited a close relationship between its microstructure and macro-properties and extensive potential applications in energy storage and conversion.

Reduced Graphene Oxide-Wrapped FeS2 Composite as Anode for High-Performance Sodium-Ion Batteries

Iron disulfide is considered to be a potential anode material for sodium-ion batteries due to its high theoretical capacity. However, its applications are seriously limited by the weak conductivity and large volume change, which results in low reversible capacity and poor cycling stability. Herein, reduced graphene oxide-wrapped FeS₂ (FeS₂/rGO) composite was fabricated to achieve excellent electrochemical performance via a facile two-step method. The introduction of rGO effectively improved the conductivity, BET surface area, and structural stability of the FeS₂ active material, thus endowing it with high specific capacity, good rate capability, as well as excellent cycling stability. Electrochemical measurements show that the FeS₂/rGO composite had a high initial discharge capacity of 1263.2 mAh g^-1 at 100 mA g^-1 and a high discharge capacity of 344 mAh g^-1 at 10 A g^-1, demonstrating superior rate performance. After 100 cycles at 100 mA g^-1, the discharge capacity remained at 609.5 mAh g^-1, indicating the excellent cycling stability of the FeS₂/rGO electrode.

Advanced Nanostructured Anode Materials for Sodium-Ion Batteries

Sodium-ion batteries (NIBs), due to the advantages of low cost and relatively high safety, have attracted widespread attention all over the world, making them a promising candidate for large-scale energy storage systems. However, the inherent lower energy density to lithium-ion batteries is the issue that should be further investigated and optimized. Toward the grid-level energy storage applications, designing and discovering appropriate anode materials for NIBs are of great concern. Although many efforts on the improvements and innovations are achieved, several challenges still limit the current requirements of the large-scale application, including low energy/power densities, moderate cycle performance, and the low initial Coulombic efficiency. Advanced nanostructured strategies for anode materials can significantly improve ion or electron transport kinetic performance enhancing the electrochemical properties of battery systems. Herein, this Review intends to provide a comprehensive summary on the progress of nanostructured anode materials for NIBs, where representative examples and corresponding storage mechanisms are discussed. Meanwhile, the potential directions to obtain high-performance anode materials of NIBs are also proposed, which provide references for the further development of advanced anode materials for NIBs.

Antimony Anchored with Nitrogen-Doping Porous Carbon as a High-Performance Anode Material for Na-Ion Batteries

Antimony represents a class of unique functional materials in sodium-ion batteries with high theoretical capacity (660 mA h g^-1). The utilization of carbonaceous materials as a buffer layer has been considered an effective approach to alleviate rapid capacity fading. Herein, the antimony/nitrogen-doping porous carbon (Sb/NPC) composite with polyaniline nanosheets as a carbon source has been successfully achieved. In addition, our strategy involves three processes, a tunable organic polyreaction, a thermal annealing process, and a cost-effective reduction reaction. The as-prepared Sb/NPC electrode demonstrates a great reversible capacity of 529.6 mA h g^-1 and an outstanding cycling stability with 97.2% capacity retention after 100 cycles at 100 mA g^-1. Even at 1600 mA g^-1, a superior rate capacity of 357 mA h g^-1 can be retained. Those remarkable electrochemical performances can be ascribed to the introduction of a hierarchical porous NPC material to which tiny Sb nanoparticles of about 30 nm were well-wrapped to buffer volume expansion and improve conductivity.

Ultraconcentrated Sodium Bis(fluorosulfonyl)imide-Based Electrolytes for High-Performance Sodium Metal Batteries

We present an ultraconcentrated electrolyte composed of 5 M sodium bis(fluorosulfonyl)imide in 1,2-dimethoxyethane for Na metal anodes coupled with high-voltage cathodes. Using this electrolyte, a very high Coulombic efficiency of 99.3% at the 120th cycle for Na plating/stripping is obtained in Na/stainless steel (SS) cells with highly reduced corrosivity toward Na metal and high oxidation durability (over 4.9 V versus Na/Na⁺) without corrosion of the aluminum cathode current collector. Importantly, the use of this ultraconcentrated electrolyte results in substantially improved rate capability in Na/SS cells and excellent cycling performance in Na/Na symmetric cells without the increase of polarization. Moreover, this ultraconcentrated electrolyte exhibits good compatibility with high-voltage Na₄Fe₃(PO₄)₂(P₂O₇) and Na_0.7(Fe_0.5Mn_0.5)O₂ cathodes charged to high voltages (>4.2 V versus Na/Na⁺), resulting in outstanding cycling stability (high reversible capacity of 109 mAh g^-1 over 300 cycles for the Na/Na₄Fe₃(PO₄)₂(P₂O₇) cell) compared with the conventional dilute electrolyte, 1 M NaPF₆ in ethylene carbonate/propylene carbonate (5/5, v/v).

One-Dimensional Yolk-Shell Sb@Ti-O-P Nanostructures as a High-Capacity and High-Rate Anode Material for Sodium Ion Batteries

Development of high energy/power density and long cycle life of anode materials is highly desirable for sodium ion batteries, because graphite anode cannot be used directly. Sb stands out from the potential candidates, due to high capacity, good electronic conductivity, and moderate sodiation voltage. Here, one-dimensional yolk-shell Sb@Ti-O-P nanostructures are synthesized by reducing core-shell Sb₂O₃@TiO₂ nanorods with NaH₂PO₂. This structure has Sb nanorod as the core to increase the capacity and Ti-O-P as the shell to stabilize the interface between electrolyte and electrode material. The gap between the core and the shell accommodates the volume change during sodiation/desodiation. These features endow the structure outstanding performances. It could deliver a capacity of about 760 mA h g^-1 after 200 cycles at 500 mA g^-1, with a capacity retention of about 94%. Even at 10 A g^-1, the reversible capacity is still at 360 mA h g^-1. The full battery of Sb@Ti-O-P//Na₃V₂(PO₄)₃-C presents a high output voltage (∼2.7 V) and a capacity of 392 mA h g^-1_anode after 150 cycles at 1 A g^-1_anode.

Synergistic effect of cross-linked carbon nanosheet frameworks and Sb on the enhancement of sodium storage performances

Cross-linked carbon nanosheets (CCNFs) are employed to anchor Sb nanoparticles to improve the sodium storage performances, and the synergistic effect of cross-linked carbon nanosheet frameworks and Sb is investigated.

Synthesis of ZnSb@C microflower composites and their enhanced electrochemical performance for lithium-ion and sodium-ion batteries

Benefiting from their special flower-like porous structure, ZnSb@C composites exhibit better electrochemical performance than ZnSb–C composites.

Size and Composition Effects in Sb-Carbon Nanocomposites for Sodium-Ion Batteries

Sodium-ion batteries are in the spotlight as viable alternatives to lithium-ion batteries in stationary storage and power grid applications. Among possible anode materials, Sb is one of the interesting candidates due to a combination of battery-type potential plateaus in the charge-discharge profiles, high capacity (theoretical capacity of 660 mAh g^-1), and demonstrated good cyclic stability. The influence of Sb particle size (particularly at the nanoscale range) and the composition of Sb-carbon composites on the electrode performance, stability, and charge storage mechanism is systematically evaluated here for the first time. A range of Sb-carbon nanocomposites with varied Sb particle size (between 50 and ∼1 nm) are studied. The control of the particle size is achieved via varying the carbon and Sb weight ratio in the precursors. The shape of charge-discharge profiles, hysteresis, and the difference in cyclic stabilities and rate performance are analyzed. The nanocomposite with the smallest particle size (∼1 nm) and the largest carbon content provides the most stable cyclic behavior and a better rate capability but suffers from an increased hysteresis between charge and discharge curves. In situ synchrotron X-ray diffraction experiments indicate that the storage mechanism in the Sb-carbon nanocomposites containing Sb nanoparticles is different from the electrodes with bulkier, micron-sized Sb particles, and the electrochemical reaction proceeds through a number of crystalline intermediates.

3D Interconnected and Multiwalled Carbon@MoS2 @Carbon Hollow Nanocables as Outstanding Anodes for Na-Ion Batteries

Currently, the specific capacity and cycling performance of various MoS₂ /carbon-based anode materials for Na-ion storage are far from satisfactory due to the insufficient structural stability of the electrode, incomplete protection of MoS₂ by carbon, difficult access of electrolyte to the electrode interior, as well as inactivity of the adopted carbon matrix. To address these issues, this work presents the rational design and synthesis of 3D interconnected and hollow nanocables composed of multiwalled carbon@MoS₂ @carbon. In this architecture, (i) the 3D nanoweb-like structure brings about excellent mechanical property of the electrode, (ii) the ultrathin MoS₂ nanosheets are sandwiched between and doubly protected by two layers of porous carbon, (iii) the hollow structure of the primary nanofibers facilitates the access of electrolyte to the electrode interior, (iv) the porous and nitrogen-doping properties of the two carbon materials lead to synergistic Na-storage of carbon and MoS₂ . As a result, this hybrid material as the anode material of Na-ion battery exhibits fast charge-transfer reaction, high utilization efficiency, and ultrastability. Outstanding reversible capacity (1045 mAh g^-1 ), excellent rate behavior (817 mAh g^-1 at 7000 mA g^-1 ), and good cycling performance (747 mAh g^-1 after 200 cycles at 700 mA g^-1 ) are obtained.

Advanced High Energy Density Secondary Batteries with Multi-Electron Reaction Materials

Secondary batteries have become important for smart grid and electric vehicle applications, and massive effort has been dedicated to optimizing the current generation and improving their energy density. Multi-electron chemistry has paved a new path for the breaking of the barriers that exist in traditional battery research and applications, and provided new ideas for developing new battery systems that meet energy density requirements. An in-depth understanding of multi-electron chemistries in terms of the charge transfer mechanisms occuring during their electrochemical processes is necessary and urgent for the modification of secondary battery materials and development of secondary battery systems. In this Review, multi-electron chemistry for high energy density electrode materials and the corresponding secondary battery systems are discussed. Specifically, four battery systems based on multi-electron reactions are classified in this review: lithium- and sodium-ion batteries based on monovalent cations; rechargeable batteries based on the insertion of polyvalent cations beyond those of alkali metals; metal-air batteries, and Li-S batteries. It is noted that challenges still exist in the development of multi-electron chemistries that must be overcome to meet the energy density requirements of different battery systems, and much effort has more effort to be devoted to this.

Double-Walled Sb@TiO2-x Nanotubes as a Superior High-Rate and Ultralong-Lifespan Anode Material for Na-Ion and Li-Ion Batteries

Double-walled Sb@TiO2- x nanotubes take full advantage of the high capacity of Sb, the good stability of TiO2- x , and their unique interaction, realizing excellent electrochemical performance both in lithium-ion batteries and sodium-ion batteries.

In Situ Binding Sb Nanospheres on Graphene via Oxygen Bonds as Superior Anode for Ultrafast Sodium-Ion Batteries

Graphene incorporation should be one effective strategy to develop advanced electrode materials for a sodium-ion battery (SIB). Herein, the micro/nanostructural Sb/graphene composite (Sb-O-G) is successfully prepared with the uniform Sb nanospheres (∼100 nm) bound on the graphene via oxygen bonds. It is revealed that the in-situ-constructed oxygen bonds play a significant role on enhancing Na-storage properties, especially the ultrafast charge/discharge capability. The oxygen-bond-enhanced Sb-O-G composite can deliver a high capacity of 220 mAh/g at an ultrahigh current density of 12 A/g, which is obviously superior to the similar Sb/G composite (130 mAh/g at 10 A/g) just without Sb-O-C bonds. It also exhibits the highest Na-storage capacity compared to Sb/G and pure Sb nanoparticles as well as the best cycling performance. More importantly, this Sb-O-G anode achieves ultrafast (120 C) energy storage in SIB full cells, which have already been shown to power a 26-bulb array and calculator. All of these superior performances originate from the structural stability of Sb-O-C bonds during Na uptake/release, which has been verified by ex situ X-ray photoelectron spectroscopies and infrared spectroscopies.

Hollow Cobalt Selenide Microspheres: Synthesis and Application as Anode Materials for Na-Ion Batteries

The electrochemical properties of hollow cobalt oxide and cobalt selenide microspheres are studied for the first time as anode materials for Na-ion batteries. Hollow cobalt oxide microspheres prepared by one-pot spray pyrolysis are transformed into hollow cobalt selenide microspheres by a simple selenization process using hydrogen selenide gas. Ultrafine nanocrystals of Co3O4 microspheres are preserved in the cobalt selenide microspheres selenized at 300 °C. The initial discharge capacities for the Co3O4 and cobalt selenide microspheres selenized at 300 and 400 °C are 727, 595, and 586 mA h g(-1), respectively, at a current density of 500 mA g(-1). The discharge capacities after 40 cycles for the same samples are 348, 467, and 251 mA h g(-1), respectively, and their capacity retentions measured from the second cycle onward are 66, 91, and 50%, respectively. The hollow cobalt selenide microspheres have better rate performances than the hollow cobalt oxide microspheres.

Ultrafine Sb nanoparticles embedded in an amorphous carbon matrix for high-performance sodium ion anode materials

SbNPs@C nanocomposite display a uniform “sea-island” structure with Sb nanoparticles' sizes ranging from 5 to 20 nm and exhibit superior electrochemical performances for SIBs anode materials.

Sb Nanoparticles Encapsulated in a Reticular Amorphous Carbon Network for Enhanced Sodium Storage

Sb nanoparticles encapsulated in 3D reticular carbon network (denoted Sb@3D RCN) film are prepared by the electrostatic spray deposition technique followed by a heat treatment. When used as a binder-free anode for a Na-ion battery, it shows excellent long-life cyclability. The unique reticular, porous, and core-shell structure of Sb@3D RCN contributes significantly to the excellent sodium storage performance.

Coupling In Situ TEM and Ex Situ Analysis to Understand Heterogeneous Sodiation of Antimony

We employed an in situ electrochemical cell in the transmission electron microscope (TEM) together with ex situ time-of-flight, secondary-ion mass spectrometry (TOF-SIMS) depth profiling, and FIB-helium ion scanning microscope (HIM) imaging to detail the structural and compositional changes associated with Na/Na(+) charging/discharging of 50 and 100 nm thin films of Sb. TOF-SIMS on a partially sodiated 100 nm Sb film gives a Na signal that progressively decreases toward the current collector, indicating that sodiation does not proceed uniformly. This heterogeneity will lead to local volumetric expansion gradients that would in turn serve as a major source of intrinsic stress in the microstructure. In situ TEM shows time-dependent buckling and localized separation of the sodiated films from their TiN-Ge nanowire support, which is a mechanism of stress-relaxation. Localized horizontal fracture does not occur directly at the interface, but rather at a short distance away within the bulk of the Sb. HIM images of FIB cross sections taken from sodiated half-cells, electrically disconnected, and aged at room temperature, demonstrate nonuniform film swelling and the onset of analogous through-bulk separation. TOF-SIMS highlights time-dependent segregation of Na within the structure, both to the film-current collector interface and to the film surface where a solid electrolyte interphase (SEI) exists, agreeing with the electrochemical impedance results that show time-dependent increase of the films' charge transfer resistance. We propose that Na segregation serves as a secondary source of stress relief, which occurs over somewhat longer time scales.

One-Dimensional Rod-Like Sb₂S₃-Based Anode for High-Performance Sodium-Ion Batteries

Due to the high theoretical capacity of 946 mAh g(-1), Sb2S3 can be employed as promising electrode material for sodium-ion batteries (SIBs). Herein, the sodium storage behaviors of one-dimensional (1D) Sb2S3-based materials (Sb2S3 and Sb2S3@C rods) are successfully studied for the first time, displaying good cyclability and rate capability owing to their unique morphology and structure. Specifically, the Sb2S3@C rods electrode presents greatly enhanced electrochemical properties, resulting from the introduction of thin carbon layers which can effectively alleviate the strain caused by the large volume change and simultaneously improve the conductivity of electrode during cycling. At a current density of 100 mA g(-1), it delivers a high capacity of 699.1 mAh g(-1) after 100 cycles, which corresponds to 95.7% of the initial reversible capacity. Even at a high current density of 3200 mA g(-1), the capacity can still reach 429 mAh g(-1). This achievement may be a significant exploration for develpoing novel 1D Sb-based materials or metal sulfide SIBs anodes.

Carbon-Confined SnO2-Electrodeposited Porous Carbon Nanofiber Composite as High-Capacity Sodium-Ion Battery Anode Material

Sodium resources are inexpensive and abundant, and hence, sodium-ion batteries are promising alternative to lithium-ion batteries. However, lower energy density and poor cycling stability of current sodium-ion batteries prevent their practical implementation for future smart power grid and stationary storage applications. Tin oxides (SnO2) can be potentially used as a high-capacity anode material for future sodium-ion batteries, and they have the advantages of high sodium storage capacity, high abundance, and low toxicity. However, SnO2-based anodes still cannot be used in practical sodium-ion batteries because they experience large volume changes during repetitive charge and discharge cycles. Such large volume changes lead to severe pulverization of the active material and loss of electrical contact between the SnO2 and carbon conductor, which in turn result in rapid capacity loss during cycling. Here, we introduce a new amorphous carbon-coated SnO2-electrodeposited porous carbon nanofiber (PCNF@SnO2@C) composite that not only has high sodium storage capability, but also maintains its structural integrity while ongoing repetitive cycles. Electrochemical results revealed that this SnO2-containing nanofiber composite anode had excellent electrochemical performance including high-capacity (374 mAh g(-1)), good capacity retention (82.7%), and large Coulombic efficiency (98.9% after 100th cycle).

A rechargeable sodium-ion battery using a nanostructured Sb–C anode and P2-type layered Na0.6Ni0.22Fe0.11Mn0.66O2 cathode

A promising example of a low cost, rechargeable sodium-ion battery efficiently combines a nanostructured Sb–C anode and P2-type layered Na_0.6Ni_0.22Fe_0.11Mn_0.66O₂ cathode.