Synergistical Coupling Interconnected ZnS/SnS2 Nanoboxes with Polypyrrole-Derived N/S Dual-Doped Carbon for Boosting High-Performance Sodium Storage

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.

Heterostructured Mn-Sn Bimetallic Sulfide Nanocubes Confined in N, S-co-Doped Carbon Framework as High-Performance Anodes for Sodium-Ion Batteries

Benefiting from its high theoretical capacity, tin disulfide (SnS2) draws abundant interest and attention for its promising practical prospect for sodium-ion batteries (SIBs). However, the huge volumetric variation in sodiation/desodiation reactions usually results in the fast decay of rate and cycling properties, which seriously obstructs its future applicable foregrounds. Herein, heterostructured Mn-Sn bimetallic sulfide nanocubes confined in N and S-codoped carbon (MSS@NSC) were rationally designed via a facile coprecipitation followed by a sulfurization strategy. When used as anodes for SIBs, the heterojunctions at the interfaces effectively accelerate the Na+ diffusion rate to promote the sodium-storage reaction kinetics. The N and S-codoped carbon provides a rapid conductive framework for the fast charge transport during the sodium-storage process. Moreover, the beneficial confinement effect of the NSC layer effectively guarantees a superb cycle property for the MSS@NSC anode. The favorable synergistic effects between the highly conductive framework of the NSC and MSS heterostructure endow the MSS@NSC anode with satisfactory electrochemical Na-storage properties.

Reduced graphene oxide-wrapped ZnS-SnS2 heterojunction bimetallic hollow cubic boxes as high-magnification and long lifespan supercapacitor anode materials

Metal sulfides have attracted extensive attention due to their excellent electrochemical performance. However, issues such as poor conductivity and severe volume expansion during charge and discharge processes affect the applications of sulfides as electrode materials. Here, a combination of coprecipitation and high-temperature sulfidation methods are employed to synthesize a ZnS-SnS2 composite with a hollow cubic structure, which is further composited with reduced graphene oxide (RGO) to form ZnS-SnS2 hollow cubic boxes encapsulated in a conductive framework of reduced graphene oxide (RGO) (denoted as ZnS-SnS2@RGO) for electrode materials. The hollow structure effectively alleviates the pulverization of ZnS-SnS2@RGO caused by volume expansion during charge and discharge processes. The heterogeneous structure formed by ZnS and SnS2 effectively reduces the electron transfer resistance of the material. The use of RGO wrapping enhances the conductivity of the ZnS-SnS2 hollow cubic boxes, and RGO's dispersion effect on the ZnS-SnS2 cubes improves particle agglomeration, further mitigating volume expansion of the material. These results indicate the outstanding electrochemical performance of heterostructural ZnS-SnS2 hollow cubic electrodes encapsulated with reduced graphene oxide as a conductive framework. The fabrication process provides a novel approach for addressing volume expansion and poor conductivity issues in other pseudocapacitive materials.

Design of heterostructured hydrangea-like FeS2/MoS2 encapsulated in nitrogen-doped carbon as high-performance anode for potassium-ion capacitors

The means of structural hybridization such as heterojunction construction and carbon-coating engineering for facilitating charge transfer and electron transport are considered viable strategies to address the challenges associated with the low rate capability and poor cycling stability of sulfide-based anodes in potassium-ion batteries (PIBs). Motivated by these concepts, we have successfully prepared a hydrangea-like bimetallic sulfide heterostructure encapsulated in nitrogen-doped carbon (FMS@NC) using a simple solvothermal method, followed by poly-dopamine wrapping and a one-step sulfidation/carbonization process. When served as an anode for PIBs, this FMS@NC demonstrates a high specific capacity (585 mAh g-1 at 0.05 A/g) and long cycling stability. Synergetic effects of mitigated volume expansions and enhanced conductivity that are responsbile for such high performance have been verified to originate from the heterostructured sulfides and the N-doped carbon matrix. Meanwhile, comprehensive characterization reveals existence of an intercalation-conversion hybrid K-ion storage mechanism in this material. Impressively, a K-ion capacitor with the FMS@NC anode and a commercial activated carbon cathode exhibits a superior energy density of up to 192 Wh kg-1, a high power density, and outstanding cycling stability. This study provides constructive guidance for designing high-performance and durable potassium-ion storage anodes for next-generation energy storage devices.

Atomic-level modulation of electron density in iron sulfides for enhancing sodium storage kinetics

Iron sulfides (FeS2) are promising anode materials for sodium ion batteries (SIBs); however, their inferior electronic conductivity, large volume swelling, and sluggish sodium ion diffusion kinetics lead to unsatisfactory rate performance and cycling durability. Heteroatom doping plays a crucial role in modifying the physicochemical properties of FeS2 anodes to enhance its sodium storage. Herein, ultra-fine Ni-doped FeS2 nanocrystals derived from a metal-organic framework (MOF) and in-situ anchored on a nitrogen doped carbon skeleton (Ni-FeS2@NC) are proposed to enhance both structural stability and reaction kinetics. Material characterization, electrochemical performance, and kinetics analysis demonstrate the critical role of Ni doping in sodium storage, particularly in accelerating Na+ diffusion efficiency. The N-doped carbon derived from the MOF can buffer the volume expansion and enhance the structural stability of electrode materials during sodiation/desodiation processes. As expected, Ni-FeS2@NC exhibits a high reversible capacity of 656.6 ± 65.1 mAh g-1 at 1.0 A g-1 after 200 cycles, superior rate performance (308.8 ± 6.0 mAh g-1 at 10.0 A g-1), and long-term cycling durability over 2000 cycles at 1.0 A g-1. Overall, this study presents an effective approach for enhancing the sodium storage performance and kinetics of anode materials for high efficiency SIBs.

State-of-the-art nanosensors and kits for the detection of antibiotic residues in milk and dairy products

Antibiotic resistance is increasingly seen as a future concern, but antibiotics are still commonly used in animals, leading to their accumulation in humans through the food chain and posing health risks. The development of nanomaterials has opened up possibilities for creating new sensing strategies to detect antibiotic residues, resulting in the emergence of innovative nanobiosensors with different benefits like rapidity, simplicity, accuracy, sensitivity, specificity, and precision. Therefore, this comprehensive review provides pertinent and current insights into nanomaterials-based electrochemical/optical sensors for the detection of antibitic residues (ANBr) across milk and dairy products. Here, we first discuss the commonly used ANBs in real products, the significance of ANBr, and also their binding/biological properties. Then, we provide an overview of the role of using different nanomaterials on the development of advanced nanobiosensors like fluorescence-based, colorimetric, surface-enhanced Raman scattering, surface plasmon resonance, and several important electrochemical nanobiosensors relying on different kinds of electrodes. The enhancement of ANB electrochemical behavior for detection is also outlined, along with a concise overview of the utilization of (bio)recognition units. Ultimately, this paper offers a perspective on the future concepts of this research field and commercialized nanomaterial-based sensors to help upgrade the sensing techniques for ANBr in dairy products.

Achieving High-Rate and Stable Sodium-Ion Storage by Constructing Okra-Like NiS2/FeS2@Multichannel Carbon Nanofibers

Transition metal sulfides (TMSs) are considered as promising anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacities. However, the relatively low electrical conductivity, large volume variation, and easy aggregation/pulverization of active materials seriously hinder their practical application. Herein, okra-like NiS2/FeS2 particles encapsulated in multichannel N-doped carbon nanofibers (NiS2/FeS2@MCNFs) are fabricated by a coprecipitation, electrospinning, and carbonization/sulfurization strategy. The combined advantages arising from the hollow multichannel structure in carbon skeleton and heterogeneous NiS2/FeS2 particles with rich interfaces can provide facile ion/electron transfer paths, ensure boosted reaction kinetics, and help maintain the structural integrity, thereby resulting in a high reversible capacity (457 mA h g-1 at 1 A g-1), excellent rate performance (350 mA h g-1 at 5 A g-1), and outstanding long-term cycling stability (93.5% retention after 1100 cycles). This work provides a facile and efficient synthetic strategy to develop TMS-based heterostructured anode materials with high-rate and stable sodium storage properties.

Rational Design of Hollow Structural Materials for Sodium-Ion Battery Anodes

The development of sodium-ion battery (SIB) anodes is still hindered by their rapid capacity decay and poor rate capabilities. Although there have been some new materials that can be used to fabricate stable anodes, SIBs are still far from wide applications. Strategies like nanostructure construction and material modification have been used to prepare more robust SIB anodes. Among all the design strategies, the hollow structure design is a promising method in the development of advanced anode materials. In the past decade, research efforts have been devoted to modifying the synthetic route, the type of templates, and the interior structure of hollow structures with high capacity and stability. A brief introduction is made to the main material systems and classifications of hollow structural materials first. Then different morphologies of hollow structural materials for SIB anodes from the latest reports are discussed, including nanoboxes, nanospheres, yolk shells, nanotubes, and other more complex shapes. The most used templates for the synthesis of hollow structrual materials are covered and the perspectives are highlighted at the end. This review offers a comprehensive discussion of the synthesis of hollow structural materials for SIB anodes, which could be potentially of use to research areas involving hollow materials design for batteries.

A cobalt-doped hollow ZnS polyhedra@porous carbon shell composite anode for high-rate sodium-ion batteries

Transition metal sulfides (TMSs) have drawn promising attention due to their low cost and high theoretical capacity for sodium storage. However, the critical issues of TMSs with huge volume changes and lower ionic/electronic conductivity are the major challenges for their practical application in sodium-ion batteries. Herein, we constructed cobalt-doped ZnS encapsulated in an N-doped carbon shell (denoted as Co-ZnS@NC), which effectively alleviates the volume expansion and improves sodium storage performance. The mechanism analysis and ion diffusion kinetics analysis (GITT, EIS, and CV) prove the acceleration of Na+ diffusion by the built-in electric field and buffer carbon layer in the Co-ZnS@NC, optimizing the cycle life and rate capability. The as-prepared Co-ZnS@NC has a high reversible capacity of 456.8 mA h g-1 after 1000 cycles at 1.0 A g-1 and superior rate capability (368.8 mA h g-1 at 20.0 A g-1), with Na metal as the counter electrode. Moreover, the assembled full cell shows a high energy density of 214.4 W h kg-1. This work provides insight on heteroatom doping for optimizing the rate capability of TMS anodes.

ZnS/SnS2 Heterostructures Encapsulated in N-Doped Carbon Nanofibers for High-Performance Alkali Metal-Ion Batteries

Heterogeneous composite ZnS/SnS2 is designed to meet various requirements for alkali metal-ion batteries. The composite is prepared using an electrostatic spinning method and encapsulated in N-doped carbon fibers after high-temperature vulcanization. The special structure of the composite provides a dependable interconnection and fast conductive network for alkali metal ions. The conductive carbon network shortens the diffusion path and greatly improves the migration efficiency of the alkali metal ions in the electrode. As expected, when the current density is 0.1 A g-1, the ZnS/SnS2@NCNFs maintain a high discharge capacity of more than 1437.5, 1321.2, and 861.6 mA h g-1 for lithium-ion, sodium-ion, and potassium-ion batteries, respectively. What is more, a full cell using a prelithiated composite anode and a LiFePO4 cathode is tested and shows excellent electrochemical performance. This work provides new perspectives for the development of novel anodes that can efficiently store alkali metal ions, as well as for the fine-structure design of materials.

MoS2/CoS heterostructures grown on carbon cloth as free-standing anodes for high-performance sodium-ion batteries

Heterostructure construction with mixed transition metal sulfides has been recognized as a promising strategy to boost the performance of sodium-ion batteries (SIBs). Herein, a carbon-decorated MoS₂/CoS heterostructure on carbon cloth (MoS₂/CoS@CC) as a free-standing anode for SIBs was synthesized via a facile growth-carbonization strategy. In the composite, the generated built-in electric field at MoS₂ and CoS heterointerfaces is beneficial for elevating the electron conductivity, thus expediting the Na-ion transport rate. Moreover, different redox potentials between MoS₂ and CoS can effectively mitigate the mechanical strain induced by repeated Na⁺ de-/intercalation, thus ensuring the structural integrity. In addition, the carbon skeleton derived from the carbonization of glucose can enhance the conductivity of the electrode and maintain the structural integrity. Consequently, the resulting MoS₂/CoS@CC electrode delivers a reversible capacity of 605 mA h g^-1 at 0.5 A g^-1 after 100 cycles, and prominent rate performance (366 mA h g^-1 at 8.0 A g^-1). Theoretical calculations also confirm that the establishment of a MoS₂/CoS heterojunction can powerfully promote the electron conductivity, thereby enhancing the Na-ion diffusion kinetics.

Defective Bi2S3 Anchored on CuS/C as an Ultrafast and Long-Life Anode for Sodium-Ion Storage

Due to the high electrical conductivity and abundant redox active sites, bimetal sulfides are highly competitive anode materials for sodium storage with long-life and high-rate. Herein, a heterostructured metal sulfide (Bi₂S₃-CuS) with a carbon-based support is prepared by calcination and ion exchange methods. The synergistic effects of the heterostructure and defective structure provide facile diffusion channels, fast Na⁺ migration, and plentiful active sites for Na⁺, which reflect in the impressive electrochemical performance with a high reversible capacity of 592.2 mA h g^-1 after 1000 cycles at 8 A g^-1. Furthermore, the Na-ion full batteries exhibit an ultra-long cycling performance with a value of 216 mA h g^-1 after 4000 cycles at 10 A g^-1. Interestingly, the defective structure of Bi₂S₃ remains after cycling. Kinetic analyses and density functional theoretical calculations clarified that the heterointerfacial structure, especially on the interface containing sulfur defects in Bi₂S₃ of Bi₂S₃-CuS, could induce feasible ion adsorption and promote ion transfer, which lays the foundation for achieving ultrafast sodiation kinetics.

Rich Self-Generated Phase Boundaries of Heterostructured VS4 /Bi2 S3 @C Nanorods for Long Lifespan Sodium-Ion Batteries

Rationally designing on sundry multiphase compounds has come into the spotlight for sodium-ion batteries (SIBs) due to enhanced structural stability and improved electrochemical performances. Nevertheless, there is still a lack of thorough understanding of the reaction mechanism of high-active phase boundaries existing between multiphase compounds. Here, a VS₄ /Bi₂ S₃ @C composite anode for SIBs with rich phase boundaries in heterostructure is successfully synthesized. In situ X-ray diffraction analyses demonstrate a multistep redox mechanism in the heterostructures and ex situ transmission electron microscopy results confirm that tremendous self-generated phase boundaries are obtained and well-maintained during cycling, dramatically leading to stable reaction interfaces and better structural integrity. Combining experimental and theoretical results, a self-built-in electric field forming between phase boundaries acts as a dominate driving force for Na⁺ transport kinetics. Benefiting from the fast reaction kinetics of phase boundaries, the heterojunction provides an efficient approach to avoid abnormal voltage failure. As expected, the VS₄ /Bi₂ S₃ @C heterostructure displays superior sodium storage performances, especially an excellent long-term cycling stability (379.0 mAh g^-1 after 1800 cycles at a current density up to 2 A g^-1 ). This work confirms a critical role of phase boundaries on superior reversibility and structural stability, and provides a strategy for analogous conversion/alloying-type anodes.

Engineering monodispersed 2 nm Sb2S3 particles embedded in a porphyrin-based MOF-derived mesoporous carbon network via an adsorption method to construct a high-performance sodium-ion battery anode

Sodium ion batteries (SIBs) are expected to replace lithium ion batteries (LIBs) as the next generation of large-scale energy storage applications because of their superior cost performance. However, the larger ionic radius of Na⁺ causes a remarkable volume expansion than that of Li⁺ during charge and discharge, which reduces the performance of the battery. In this work, we engineered a composite material in that monodispersed 2 nm Sb₂S₃ particles are uniformly loaded into a carbon matrix (Sb₂S₃/CZM), which is obtained by carbonization of a zirconium-based MOF with adsorption of Sb. The obtained composite material has a high specific surface area in favor of mass transfer, and the porous structure can resist many volume changes in the circulation process. Moreover, the ultrafine Sb₂S₃ particles are well-distributed in the composite material, which increases the utilization of the active substance and is promising for the storage of Na⁺. Based on its unique structure, the Sb₂S₃/CZM composite shows a specific capacity of 550 mA h g^-1 at 100 mA g^-1 and an excellent cycling stability of 88.9% retention after 1000 cycles at 3 A g^-1. The excellent electrochemical performance provides enlightenment for the rational design of hierarchical heterostructures for energy storage applications.

Enabling Reversible Reaction by Uniform Distribution of Heterogeneous Intermediates on Defect-Rich SnSSe/C Layered Heterostructure for Ultralong-Cycling Sodium Storage

2D layered Sn-based materials have attracted enormous attention due to their remarkable performance in sodium-ion batteries. Nevertheless, this promising candidate involves a complex Na⁺ -storage process with multistep conversion-alloying reactions, which induces the uneven dispersion of heterogeneous intermediate accompanied by severe agglomeration of metallic Sn⁰ , inescapably resulting in poor reaction reversibility with sluggish rate capability and inferior cyclic lifespan. Herein, a delicately layered heterostructure SnSSe/C consisting of defect-rich SnSSe and graphene is designed and successfully achieved via a facile hydrothermal process. The equal anionic substitution of Se in SnSSe crystal can trigger numerous defects, which can not only facilitate Na⁺ diffusion but also accelerate the nucleation process by inducing quantum-dot-level uniform distribution of heterogeneous intermediates, Na₂ Se/Na₂ S and Sn⁰ . Concurrently, in situ formed uniform Na₂ Se/Na₂ S grain boundaries confined by this unique layered heterostructure may effectively suppress the agglomeration of metallic Sn⁰ nanograins and boost the reversibility of conversion-alloying reaction. As a result, the SnSSe/C displays significant improvement in Na-storage performance, in terms of remarkable rate capability and ultralong cycling lifespan. This work, focusing on controlling intermediate distribution, provides an effective strategy to boost reaction reversibility, which can be wildly employed in conversion-based electrodes for energy storage regions.

Carbon-coated MoS1.5Te0.5 nanocables for efficient sodium-ion storage in non-aqueous dual-ion batteries

Sodium-based dual-ion batteries have received increased attention owing to their appealing cell voltage (i.e., >3 V) and cost-effective features. However, the development of high-performance anode materials is one of the key elements for exploiting this electrochemical energy storage system at practical levels. Here, we report a source-template synthetic strategy for fabricating a variety of nanowire-in-nanotube MS_xTe_y@C (M = Mo, W, Re) structures with an in situ-grown carbon film coating, termed as nanocables. Among the various materials prepared, the MoS_1.5Te_0.5@C nanocables are investigated as negative electrode active material in combination with expanded graphite at the positive electrode and NaPF₆-based non-aqueous electrolyte solutions for dual-ion storage in coin cell configuration. As a result, the dual-ion lab-scale cells demonstrate a prolonged cycling lifespan with 97% capacity retention over 1500 cycles and a reversible capacity of about 101 mAh g⁻¹ at specific capacities (based on the mass of the anode) of 1.0 A g⁻¹ and 5.0 A g⁻¹, respectively.

Sodium-based dual-ion batteries are promising electrochemical energy storage devices. Here, the authors report a source-template synthetic strategy to prepare carbon-coated MoS_1.5Te_0.5 nanocables and their use as anode active materials in Na-based dual ion cells.

Ultrafast and Ultrastable Heteroarchitectured Porous Nanocube Anode Composed of CuS/FeS2 Embedded in Nitrogen-Doped Carbon for Use in Sodium-Ion Batteries

The enhancement of the structural stability of conversion-based metal sulfides at high current densities remains a major challenge in realizing the practical application of sodium-ion batteries (SIBs). The instability of metal sulfides is caused by the large volume variation and sluggish reaction kinetics upon sodiation/desodiation. To overcome this, herein, a heterostructured nanocube anode composed of CuS/FeS₂ embedded in nitrogen-doped carbon (CuS/FeS₂ @NC) is synthesized. Size- and shape-controlled porous carbon nanocubes containing metallic nanoparticles are synthesized by the two-step pyrolysis of a bimetallic Prussian blue analog (PBA) precursor. The simple sulfurization-induced formation of highly conductive CuS along with FeS₂ facilitates sodium-ion diffusion and enhances the redox reversibility upon cycling. The mesoporous carbon structure provides excellent electrolyte impregnation, efficient charge transport pathways, and good volume expansion buffering. The CuS/FeS₂ @NC nanocube anode exhibits excellent sodium storage characteristics including high desodiation capacity (608 mAh g^-1 at 0.2 A g^-1 ), remarkable long-term cycle life (99.1% capacity retention after 300 cycles at 5 A g^-1 ), and good rate capability up to 5 A g^-1 . The simple, facile synthetic route combined with the rational design of bimetallic PBA nanostructures can be widely utilized in the development of conversion-based metal sulfides and other high-capacity anode materials for high-performance SIBs.

Synthesis of Heterostructured Dual metal Sulfides by High-temperature Mixing Hydrothermal Method as a Ultra-high Rate Anode for Li-ion Batteries

In this research, an novel approach is reported to fabricate flower-like Cu2S/MoS2 microspheres anchored on graphene (Cu2S/MoS2/rGO) by using a high-temperature mixing hydrothermal method (HTMHM). In detail, the molybdenum source...

Shape-Designable and Reconfigurable All-Paper Sensor through the Sandwich Architecture for Pressure/Proximity Detection

All-paper sensors that are capable of free cutting and folding maximize the merits of papers, which fully utilize the unique potential of papers in cost effectiveness, flexibility, disposability, biodegradability, and a flexible design. However, most of the paper sensors have applied metals as the electrodes and polyimide/polydimethylsiloxane as the encapsulation/sensitive layers, limiting the advantages of the paper sensor. In this work, an all-paper, shape-designable, and reconfigurable capacitive pressure/proximity sensor is fabricated with multilayered tissue paper as the dielectric and polypyrrole printer paper as the electrode/encapsulation. Without the restriction of heterogeneous materials, the all-paper components enable the sensors' flexible shape design for freely cuttable and foldable 2D and 3D sensors including a 2D braille keyboard and even allow reconfiguration from a 3D box sensor to a 3D candy sensor. The all-paper sensor presents superior pressure-sensing performance (0.96 kPa^-1 at <1.76 kPa and 0.09 kPa^-1 at 1.76-22 kPa) and proximity-sensing ability. The sensing mechanism of the sensor is directly revealed from tissue paper changes using in situ 3D microscopy and dielectric measurement experiments. These results provide inspiration for realizing shape-designable and reconfigurable 3D sensors and fully demonstrate the application potential in omnidirectional perception, stretchable sensors, and green electronics.

Conversion-Alloying Anode Materials for Sodium Ion Batteries

The past decade has witnessed a rapidly growing interest toward sodium ion battery (SIB) for large-scale energy storage in view of the abundance and easy accessibility of sodium resources. Key to addressing the remaining challenges and setbacks and to translate lab science into commercializable products is the development of high-performance anode materials. Anode materials featuring combined conversion and alloying mechanisms are one of the most attractive candidates, due to their high theoretical capacities and relatively low working voltages. The current understanding of sodium-storage mechanisms in conversion-alloying anode materials is presented here. The challenges faced by these materials in SIBs, and the corresponding improvement strategies, are comprehensively discussed in correlation with the resulting electrochemical behavior. Finally, with the guidance and perspectives, a roadmap toward the development of advanced conversion-alloying materials for commercializable SIBs is created.

Structural Engineering of Hollow Microflower-like CuS@C Hybrids as Versatile Electrochemical Sensing Platform for Highly Sensitive Hydrogen Peroxide and Hydrazine Detection

Designing metal sulfides with unique configurations and exploring their electrochemical activities for hydrogen peroxide (H₂O₂) and hydrazine (N₂H₄) is challenging and desirable for various fields. Herein, hollow microflower-like CuS@C hybrids were successfully assembled and further exploited as a versatile electrochemical sensing platform for H₂O₂ reduction and N₂H₄ oxidation, of which the elaborate strategies make the perfect formation of hollow architecture, providing considerable electrocatalytic sites and fast charge transfer rate, while the appropriate introduction polydopamine-derived carbon skeleton facilitates the electronic conductivity and boosts structural robustness, thus generating wide linear range (0.05-14 and 0.01-10 mM), low detection limit (0.22 μM and 0.07 μM), and a rather low overpotential (-0.15 and -0.05 V) toward H₂O₂ and N₂H₄, as well as good selectivity, excellent reproducibility, and admirable long-term stability. It should be highlighted that the operating potentials can compare favorably with those of some reported H₂O₂ and N₂H₄ sensors based on noble metals. In addition, good recoveries and acceptable relative standard deviations (RSDs) attained in serum and water samples fully verify the accuracy and anti-interference capability of our proposed sensor systems. These results not only elucidate an effective structural nanoengineering strategy for electroanalytical science but also advance the rational utilization of H₂O₂ and N₂H₄ in practicability.

Solution-Synthesized SnSe1-xSx: Dual-Functional Materials with Enhanced Electrochemical Storage and Thermoelectric Performance

The exploration of materials with multifunctional properties, such as energy harvesting and storage, is crucial in integrated energy devices and technologies. Herein, through an organic-free "soft chemical" solution method, a series of dual-functional SnSe_1-xS_x (x = 0, 0.1, 0.2, 0.3, 0.4, and 0.5) nanoparticles have been developed toward high-performance electrochemical energy storage and thermoelectric conversion. Among the synthesized S-substituted SnSe, SnSe_0.5S_0.5 exhibits the highest rate capacity (546.1 mA h g^-1 at 2 A g^-1) and the best reversible capacity (556.2 mA h g^-1 at 0.1 A g^-1 after 100 cycles), which are much enhanced compared to those of SnSe. Density functional theory calculation confirms that the composition regulation by S substitution can lower the diffusion barrier of Li⁺, boost the diffusion rate of Li⁺, and in turn enhance the electrochemical kinetics, thus increasing the Li⁺ storage performance. Meanwhile, partially replacing Se by S decreases the lattice thermal conductivity, leading to an improved peak zT of 0.64 at 773 K in SnSe_0.9S_0.1, which is enhanced compared to the value for SnSe obtained at the same temperature. This study develops a combined composition tuning-nanostructuring approach for optimizing the electrochemical and thermoelectric performance of dual-functional SnSe.

Chemical Heterointerface Engineering on Hybrid Electrode Materials for Electrochemical Energy Storage

The chemical heterointerfaces in hybrid electrode materials play an important role in overcoming the intrinsic drawbacks of individual materials and thus expedite the in-depth development of electrochemical energy storage. Benefiting from the three enhancement effects of accelerating charge transport, increasing the number of storage sites, and reinforcing structural stability, the chemical heterointerfaces have attracted extensive interest and the electrochemical performances of hybrid electrode materials have been significantly optimized. In this review, recent advances regarding chemical heterointerface engineering in hybrid electrode materials are systematically summarized. Especially, the intrinsic behaviors of chemical heterointerfaces on hybrid electrode materials are refined based on built-in electric field, van der Waals interaction, lattice mismatch and connection, electron cloud bias and chemical bond, and their combination. The strategies for introducing chemical heterointerfaces are classified into in situ local transformation, in situ growth, cosynthesis, and other strategy. The recent progress about the chemical heterointerfaces engineering specially focusing on metal-ion batteries, supercapacitors, and Li-S batteries are introduced in detail. Furthermore, the classification and characterization of chemical heterointerfaces are briefly described. Finally, the emerging challenges and perspectives about future directions of chemical heterointerface engineering are proposed.

Unlocking Rapid and Robust Sodium Storage Performance of Zinc-Based Sulfide via Indium Incorporation

Zinc sulfide (ZnS) exhibits promise in sodium-ion batteries (SIBs) because of its low operation voltage and high theoretical specific capacity. However, pristine ZnS is not adequate in realizing rapid and robust sodium storage owing to its low reversibility, poor structure stability, and sluggish kinetics. To date, most efforts focus on utilizing carbonaceous incorporation to improve its electrochemical performances. Nevertheless, it remains an arduous challenge for realizing superior rate capability while obtaining stable cycling. Herein, inspired by the crystal structure of hexagonal ZnIn₂S₄, which possesses an intrinsic layered feature with larger unit-cell volume versus that of ZnS, indium incorporation is thus deployed as an immediate remedy. In/ex situ investigations combined with density functional theory calculations are conducted to reveal the superior kinetics, high reversibility, and good structure stability of ZnIn₂S₄. Notably, the formed indium-based derivatives during cycling manifest a Na⁺ (de)intercalation process, thereby exciting a synergetic mechanism to stabilize electrochemical cycling. As a result, the electrochemical performances of Zn-based sulfide are significantly improved via the indium incorporation. Furthermore, a full cell based on the ZnIn₂S₄ anode with the superior electrochemical performance is developed. This work provides an effective tactic of heteroatom incorporation for optimizing structure as well as exciting a complementary reaction process toward developing superior anodes for high-performance alkali-ion batteries.

Recent Progress on the Alloy-Based Anode for Sodium-Ion Batteries and Potassium-Ion Batteries

High-energy batteries with low cost are urgently needed in the field of large-scale energy storage, such as grid systems and renewable energy sources. Sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs) with alloy-based anodes provide huge potential due to their earth abundance, high capacity, and suitable working potential, and are recognized as attractive alternatives for next-generation batteries system. Although some important breakthroughs have been reported, more significant improvements are still required for long lifetime and high energy density. Herein, the latest progress for alloy-based anodes for SIBs and PIBs is summarized, mainly including Sn, Sb, Ge, Bi, Si, P, and their oxides, sulfides, selenides, and phosphides. Specifically, the material designs for the desired Na⁺ /K⁺ storage performance, phase transform, ionic/electronic transport kinetics, and specific chemical interactions are discussed. Typical structural features and research strategies of alloy-based anodes, which are used to facilitate processes in battery development for SIBs and PIBs, are also summarized. The perspective of future research of SIBs and PIBs is outlined.

A Z-scheme heterostructure constructed from ZnS nanospheres and Ni(OH)2 nanosheets to enhance the photocatalytic hydrogen evolution

ZnS and Ni(OH)₂ form a Z-scheme heterostructure, and the synergy between them provides a new hydrogen-producing active center for each material.

Structural Engineering of SnS2 Encapsulated in Carbon Nanoboxes for High-Performance Sodium/Potassium-Ion Batteries Anodes

Conversion-alloying type anode materials like metal sulfides draw great attention due to their considerable theoretical capacity for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). However, poor conductivity, severe volume change, and harmful aggregation of the material during charge/discharge lead to unsatisfying electrochemical performance. Herein, a facile and green strategy for yolk-shell structure based on the principle of metal evaporation is proposed. SnS₂ nanoparticle is encapsulated in nitrogen-doped hollow carbon nanobox (SnS₂ @C). The carbon nanoboxes accommodate the volume change and aggregation of SnS₂ during cycling, and form 3D continuous conductive carbon matrix by close contact. The well-designed structure benefits greatly in conductivity and structural stability of the material. As expected, SnS₂ @C exhibits considerable capacity, superior cycling stability, and excellent rate capability in both SIBs and PIBs. Additionally, in situ Raman technology is unprecedentedly conducted to investigate the phase evolution of polysulfides. This work provides an avenue for facilely constructing stable and high-capacity metal dichalcogenide based anodes materials with optimized structure engineering. The proposed in-depth electrochemical measurements coupled with in situ and ex situ characterizations will provide fundamental understandings for the storage mechanism of metal dichalcogenides.

Recent Advances on Mixed Metal Sulfides for Advanced Sodium-Ion Batteries

Sodium-ion batteries (SIBs) have drawn enormous attention in the past few years from both academic and industrial battery communities in view of the fascinating advantages of rich abundance and low cost of sodium resources. Among various electrode materials, mixed metal sulfides (MMSs) stand out as promising negative electrode materials for SIBs considering their superior structural and compositional advantages, such as decent electrochemical reversibility, high electronic conductivity, and rich redox reactions. Here, a summary of some recent developments in the rational design and synthesis of various kinds of MMSs with tailorable architectures, structural/compositional complexity, controllable morphologies, and enhanced electrochemical properties is presented. The effect of structural engineering and compositional design of MMSs on the sodium storage properties is highlighted. It is anticipated that further innovative works on the material design of advanced electrodes for batteries can be inspired.

Composition and Architecture Design of Double-Shelled Co0.85 Se1- x Sx @Carbon/Graphene Hollow Polyhedron with Superior Alkali (Li, Na, K)-Ion Storage

The exploration of materials with reversible and stable electrochemical performance is crucial in energy storage, which can (de) intercalate all the alkali-metal ions (Li⁺ , Na⁺ , and K⁺ ). Although transition-metal chalcogenides are investigated continually, the design and controllable preparation of hierarchical nanostructure and subtle composite withstable properties are still great challenges. Herein, component-optimal Co_0.85 Se_{1- x} S_x nanoparticles are fabricated by in situ sulfidization of metal organic framework, which are wrapped by the S-doped graphene, constructing a hollow polyhedron framework with double carbon shells (CoSSe@C/G). Benefiting from the synergistic effect of composition regulation and architecture design by S-substitution, the electrochemical kinetic is enhanced by the boosted electrochemistry-active sites, and the volume variation is mitigated by the designed structure, resulting in the advanced alkali-ion storage performance. Thus, it delivers an outstanding reversible capacity of 636.2 mAh g^-1 at 2 A g^-1 after 1400 cycles for Li-ion batteries. Remarkably, satisfactory initial charge capacities of 548.1 and 532.9 mAh g^-1 at 0.1 A g^-1 can be obtained for Na-ion and K-ion batteries, respectively. The prominent performance combined with the theory calculation confirms that the synergistic strategy can improve the alkali-ion transportation and structure stability, providing an instructive guide for designing high-performance anode materials for universal alkali-ion storage.

Bimetallic Sulfide Sb2S3@FeS2 Hollow Nanorods as High-Performance Anode Materials for Sodium-Ion Batteries

Constructing a heterojunction and introducing an interfacial interaction by designing ideal structures have the inherent advantages of optimizing electronic structures and macroscopic mechanical properties. An exquisite hierarchical heterogeneous structure of bimetal sulfide Sb₂S₃@FeS₂ hollow nanorods embedded into a nitrogen-doped carbon matrix is fabricated by a concise two-step solvothermal method. The FeS₂ interlayer expands in situ grow on the interface of hollow Sb₂S₃ nanorods within the nitrogen-doped graphene matrix, forming a delicate heterostructure. Such a well-designed architecture affords rapid Na⁺ diffusion and improves charge transfer at the heterointerfaces. Meanwhile, the strongly synergistic coupling interaction among the interior Sb₂S₃, interlayer FeS₂, and external nitrogen-doped carbon matrix creates a stable nanostructure, which extremely accelerates the electronic/ion transport and effectively alleviates the volume expansion upon long cyclic performance. As a result, the composite, as an anode material for sodium-ion batteries, exhibits a superior rate capability of 537.9 mAh g^-1 at 10 A g^-1 and excellent cyclic stability with 85.7% capacity retention after 1000 cycles at 5 A g^-1. Based on the DFT calculation, the existing constructing heterojunction in this composite can not only optimize the electronic structure to enhance the conductivity but also favor the Na₂S adsorption energy to accelerate the reaction kinetics. The outstanding electrochemical performance sheds light on the strategy by the rational design of hierarchical heterogeneous nanostructures for energy storage applications.

In situ chemically encapsulated and controlled SnS2 nanocrystal composites for durable lithium/sodium-ion batteries

SnS2 as the promising anode for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs) still encounters the undesirable rate performance and cycle stability. Herein, a unique stable structure is developed, where the SnS2 nanocrystals (NCs) are sturdily encapsulated by carbon shells anchored on a reduced graphene oxide (rGO) via the one-pot solvothermal process. The well-controlled carbon shells provide the enduring protection for SnS2 NCs through C-S covalent bonds from the corrosion of electrolyte and pulverization of structure. Moreover, both experimental results and density functional theory (DFT) calculations demonstrate that the carbon protective shell effectively enhances the structure stability and conductivity of the resulting materials. Interestingly, the size of SnS2 NCs and the thickness of carbon shells are accurately controlled by regulating the content of glucose. Aided by the advanced electron/ion transfer kinetics and structure stability, the SnS2-based electrode exhibits desired lithium/sodium storage performance and unprecedented long-term cycling stability (capacity retention of 74.7% after 1000 cycles at 2 A g-1 for LIBs and 102% after 200 cycles at 500 mA g-1 for SIBs). This work develops a method for promoting the practical applications and large-scale production of SnS2 composites for energy storage devices.

Boosting Sodium Storage of Fe1-xS/MoS2 Composite via Heterointerface Engineering

Improving the cycling stability of metal sulfide-based anode materials at high rate is of great significance for advanced sodium ion batteries. However, the sluggish reaction kinetics is a big obstacle for the development of high-performance sodium storage electrodes. Herein, we have rationally engineered the heterointerface by designing the Fe_1-xS/MoS₂ heterostructure with abundant "ion reservoir" to endow the electrode with excellent cycling stability and rate capability, which is proved by a series of in and ex situ electrochemical investigations. Density functional theory calculations further reveal that the heterointerface greatly decreases sodium ion diffusion barrier and facilitates charge-transfer kinetics. Our present findings not only provide a deep analysis on the correlation between the structure and performance, but also draw inspiration for rational heterointerface engineering toward the next-generation high-performance energy storage devices.

Deeply Nesting Zinc Sulfide Dendrites in Tertiary Hierarchical Structure for Potassium Ion Batteries: Enhanced Conductivity from Interior to Exterior

Transition metal sulfides are deemed as attractive anode materials for potassium-ion batteries (KIBs) due to their high theoretical capacities based on conversion and alloying reaction. However, the main challenges are the low electronic conductivity, huge volume expansion, and consequent formation of unstable solid electrolyte interphase (SEI) upon potassiation/depotassiation. Herein, zinc sulfide dendrites deeply nested in the tertiary hierarchical structure through a solvothermal-pyrolysis process are designed as an anode material for KIBs. The tertiary hierarchical structure is composed of the primary ultrafine ZnS nanorods, the secondary carbon nanosphere, and the tertiary carbon-encapsulated ZnS subunits nanosphere structure. The architectural design of this material provides a stable diffusion path and enhances effective conductivity from the interior to exterior for both K⁺ ions and electrons, buffers the volume expansion, and constructs a stable SEI during cycling. A stable specific capacity of 330 mAh g^-1 is achieved after 100 cycles at the current density of 50 mA g^-1 and 208 mAh g^-1 at 500 mA g^-1 over 300 cycles. Using density functional theory calculations, we discover the interactions between ZnS and carbon interface can effectively decrease the K⁺ ions diffusion barrier and therefore promote the reversibility of K⁺ ions storage.

Facile synthesis of a molybdenum phosphide@carbon nanocomposite as an advanced anode material for sodium-ion batteries

The MoP@C nanocomposite was successfully fabricated via a facile sol–gel approach, which demonstrated excellent electrochemical properties as a sodium-ion battery anode.

Room-temperature solution synthesis of ZnMn2O4 nanoparticles for advanced electrochemical lithium storage

Taking advantage of synergistic effects, the ternary metal oxides have attracted tremendous interest. Herein, ZnMn₂O₄ nano-particles have been fabricated via a facile one-step approach at room temperature, that of simply mixing ZnO and MnO in KOH aqueous solution without templates. When used as an anode for lithium ion batteries, it delivers the excellent structure stability (1028.9 mA h g⁻¹ at 1.0 A g⁻¹ after 400 cycles). Surprisingly, the low-cost and eco-friendly route provides a novel strategy to synthesize the mixed transition metal oxide electrodes with readily scaled-up production.

ZnMn₂O₄ nanoparticles were fabricated via a low-cost and ecofriendly one-step approach at room temperature. The particles exhibited excellent structure stability and superior lithium storage.