Molybdenum Disulfide Based Nanomaterials for Rechargeable Batteries

The rapid development of electrochemical energy storage systems requires new electrode materials with high performance. As a two-dimensional material, molybdenum disulfide (MoS₂) has attracted increasing interest in energy storage applications due to its layered structure, tunable physical and chemical properties, and high capacity. In this review, the atomic structures and properties of different phases of MoS₂ are first introduced. Then, typical synthetic methods for MoS₂ and MoS₂-based composites are presented. Furthermore, the recent progress in the design of diverse MoS₂-based micro/nanostructures for rechargeable batteries, including lithium-ion, lithium-sulfur, sodium-ion, potassium-ion, and multivalent-ion batteries, is overviewed. Additionally, the roles of advanced in situ/operando techniques and theoretical calculations in elucidating fundamental insights into the structural and electrochemical processes taking place in these materials during battery operation are illustrated. Finally, a perspective is given on how the properties of MoS₂-based electrode materials are further improved and how they can find widespread application in the next-generation electrochemical energy-storage systems.     

Ultrathin MoS2 Nanosheets Supported on N‐doped Carbon Nanoboxes with Enhanced Lithium Storage and Electrocatalytic Properties

Molybdenum disulfide (MoS₂) has received considerable interest for electrochemical energy storage and conversion. In this work, we have designed and synthesized a unique hybrid hollow structure by growing ultrathin MoS₂ nanosheets on N‐doped carbon shells (denoted as C@MoS₂ nanoboxes). The N‐doped carbon shells can greatly improve the conductivity of the hybrid structure and effectively prevent the aggregation of MoS₂ nanosheets. The ultrathin MoS₂ nanosheets could provide more active sites for electrochemical reactions. When evaluated as an anode material for lithium‐ion batteries, these C@MoS₂ nanoboxes show high specific capacity of around 1000 mAh g^?1, excellent cycling stability up to 200 cycles, and superior rate performance. Moreover, they also show enhanced electrocatalytic activity for the electrochemical hydrogen evolution.     

Unraveling the Beneficial Microstructure Evolution in Pyrite for Boosted Lithium Storage Performance

Pyrite FeS₂ as a high-capacity electrode material for lithium-ion batteries (LIBs) is hindered by its unstable cycling performance owing to the large volume change and irreversible phase segregation from coarsening of Fe. Here, the beneficial microstructure evolution in MoS₂-modified FeS₂ is unraveled during the cycling process; the microstructure evolution is responsible for its significantly boosted lithium storage performance, making it suitable for use as an anode for LIBs. Specifically, the FeS₂/MoS₂ displays a long cycle life with a capacity retention of 116 % after 600 cycles at 0.5 A g⁻¹, which is the best among the reported FeS₂-based materials so far. A series of electrochemical tests and structural characterizations substantially revealed that the introduced MoS₂ in FeS₂ experiences an irreversible electrochemical reaction and thus the in situ formed metallic Mo could act as the conductive buffer layer to accelerate the dynamics of Li⁺ diffusion and electron transport. More importantly, it can guarantee the highly reversible conversion in lithiated FeS₂ by preventing Fe coarsening. This work provides a fundamental understanding and an effective strategy towards the microstructure evolution for boosting lithium storage performances for other metal sulfide-based materials.     

Nitrogen‐Doped Carbon Embedded MoS2 Microspheres as Advanced Anodes for Lithium‐ and Sodium‐Ion Batteries

Rational design and synthesis of advanced anode materials are extremely important for high‐performance lithium‐ion and sodium‐ion batteries. Herein, a simple one‐step hydrothermal method is developed for fabrication of N‐C@MoS₂ microspheres with the help of polyurethane as carbon and nitrogen sources. The MoS₂ microspheres are composed of MoS₂ nanoflakes, which are wrapped by an N‐doped carbon layer. Owing to its unique structural features, the N‐C@MoS₂ microspheres exhibit greatly enhanced lithium‐ and sodium‐storage performances including a high specific capacity, high rate capability, and excellent capacity retention. Additionally, the developed polyurethane‐assisted hydrothermal method could be useful for the construction of many other high‐capacity metal oxide/sulfide composite electrode materials for energy storage.     

Carbon Nanofibers Decorated with Molybdenum Disulfide Nanosheets: Synergistic Lithium Storage and Enhanced Electrochemical Performance

Traditional lithium‐ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS₂), is now reported. A synergistic effect was observed for the two‐component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS₂) to MoS₃ in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high‐rate capability, suggesting its potential application in high‐energy lithium‐ion batteries.     

Three‐Dimensional MoS2 Hierarchical Nanoarchitectures Anchored into a Carbon Layer as Graphene Analogues with Improved Lithium Ion Storage Performance

Much attention has recently been focused on the synthesis and application of graphene analogues of layered nanomaterials owing to their better electrochemical performance than the bulk counterparts. We synthesized graphene analogue of 3D MoS₂ hierarchical nanoarchitectures through a facile hydrothermal route. The graphene‐like MoS₂ nanosheets are uniformly dispersed in an amorphous carbon matrix produced in situ by hydrothermal carbonization. The interlaminar distance between the MoS₂ nanosheets is about 1.38 nm, which is far larger than that of bulk MoS₂ (0.62 nm). Such a layered architecture is especially beneficial for the intercalation and deintercalation of Li⁺. When tested as a lithium‐storage anode material, the graphene‐like MoS₂ hierarchical nanoarchitectures exhibit high specific capacity, superior rate capability, and enhanced cycling performance. This material shows a high reversible capacity of 813.5 mAh g^?1 at a current density of 1000 mA g^?1 after 100 cycles and a specific capacity as high as 600 mAh g^?1 could be retained even at a current density of 4000 mA g^?1. The results further demonstrate that constructing 3D graphene‐like hierarchical nanoarchitectures can effectively improve the electrochemical performance of electrode materials.     

Antimony anchored in MoS2 nanosheets with N-doped carbon coating to boost potassium storage performance

Potassium ions batteries (PIBs) have been considered as promising energy storage systems owning to potassium rich natural abundances. However, the difficult reaction kinetics and poor cycling of electrode restrict the further development of PIBs. In this work, antimony anchored in MoS₂ nanosheets with N-doped carbon coating (Sb/MoS₂/NCs) are prepared and evaluated as anode for PIBs. In the unique Sb/MoS₂/NCs structure, the volume expansion of Sb particles could be effectively buffered by the around MoS₂ structure. The defects in MoS₂ nanosheets provide more electrochemical reaction sites for sufficient K⁺ insertion/extraction. Furthermore, the N-doped carbon can further accommodate the volume expansion and improve the electronic conductivity of Sb/MoS₂/NCs composites. Due to the above advantages, the Sb/MoS₂/NCs anode delivers a capacity of 235 mAh/g at 50 mA/g after 78 cycles. This work provides a prospective strategy to design advanced anode materials for PIBs using MoS₂ and antimony composites.     

Vertically Grown Few-Layer MoS2 Nanosheets on Hierarchical Carbon Nanocages for Pseudocapacitive Lithium Storage with Ultrahigh-Rate Capability and Long-Term Recyclability

Molybdenum disulfide (MoS₂) is an intensively studied anode material for lithium-ion batteries (LIBs) owing to its high theoretical capacity, but it is still confronted by severe challenges of unsatisfactory rate capability and cycle life. Herein, few-layer MoS₂ nanosheets, vertically grown on hierarchical carbon nanocages (hCNC) by a facile hydrothermal method, introduce pseudocapacitive lithium storage owing to the highly exposed MoS₂ basal planes, enhanced conductivity, and facilitated electrolyte access arising from good hybridization with hCNC. Thus, the optimized MoS₂/hCNC exhibits reversible capacities of 1670 mAh g⁻¹ at 0.1 A g⁻¹ after 50 cycles, 621 mAh g⁻¹ at 5.0 A g⁻¹ after 500 cycles, and 196 mAh g⁻¹ at 50 A g⁻¹ after 2500 cycles, which are among the best for MoS₂-based anode materials. The specific power and specific energy, which can reach 16.1 kW and 252.8 Wh after 3000 cycles, respectively, indicate great potential in high-power and long-life LIBs. These findings suggest a promising strategy for exploring advanced anode materials with high reversible capacity, high-rate capability, and long-term recyclability.     

Double-Shelled Hollow SiO2@N-C Nanofiber Boosts the Lithium Storage Performance of [PMo12O40]3−

Polyoxometalates (POMs)-based materials, with high theoretical capacities and abundant reversible multi-electron redox properties, are considered as promising candidates in lithium-ion storage. However, the poor electronic conductivity, low specific surface area and high solubility in the electrolyte limited their practical applications. Herein, a double-shelled hollow PMo₁₂−SiO₂@N−C nanofiber (PMo₁₂−SiO₂@N−C, where PMo₁₂ is [PMo₁₂O₄₀]³⁻, N−C is nitrogen-doped carbon) was fabricated for the first time by combining coaxial electrospinning technique, thermal treatment and electrostatic adsorption. As an anode material for LIBs, the PMo₁₂−SiO₂@N−C delivered an excellent specific capacity of 1641 mA h g⁻¹ after 1000 cycles under 2 A g⁻¹. The excellent electrochemical performance benefited from the unique double-shelled hollow structure of the material, in which the outermost N−C shell cannot only hinder the agglomeration of PMo₁₂, but also improve its electronic conductivity. The SiO₂ inner shell can efficiently avoid the loss of active components. The hollow structure can buffer the volume expansion and accelerate Li⁺ diffusion during lithiation/delithiation process. Moreover, PMo₁₂ can greatly reduce charge-resistance and facilitate electron transfer of the entire composites, as evidenced by the EIS kinetics study and lithium-ion diffusion analysis. This work paves the way for the fabrication of novel POM-based LIBs anode materials with excellent lithium storage performance.     

Metal–Organic Frameworks-Derived Mesoporous Si/SiOx@NC Nanospheres as a Long-Lifespan Anode Material for Lithium-Ion Batteries

Silicon (Si)-based anode materials with suitable engineered nanostructures generally have improved lithium storage capabilities, which provide great promise for the electrochemical performance in lithium-ion batteries (LIBs). Herein, a metal–organic framework (MOF)-derived unique core–shell Si/SiO_x@NC structure has been synthesized by a facile magnesio-thermic reduction, in which the Si and SiO_x matrix were encapsulated by nitrogen (N)-doped carbon. Importantly, the well-designed nanostructure has enough space to accommodate the volume change during the lithiation/delithiation process. The conductive porous N-doped carbon was optimized through direct carbonization and reduction of SiO₂ into Si/SiO_x simultaneously. Benefiting from the core–shell structure, the synthesized product exhibited enhanced electrochemical performance as an anode material in LIBs. Particularly, the Si/SiO_x@NC-650 anode showed the best reversible capacities up to 724 and 702 mAh g⁻¹ even after 100 cycles. The excellent cycling stability of Si/SiO_x@NC-650 may be attributed to the core–shell structure as well as the synergistic effect between the Si/SiO_x and MOF-derived N-doped carbon.     

A Core–Shell Fe/Fe2O3 Nanowire as a High‐Performance Anode Material for Lithium‐Ion Batteries

The preparation of novel one‐dimensional core–shell Fe/Fe₂O₃ nanowires as anodes for high‐performance lithium‐ion batteries (LIBs) is reported. The nanowires are prepared in a facile synthetic process in aqueous solution under ambient conditions with subsequent annealing treatment that could tune the capacity for lithium storage. When this hybrid is used as an anode material for LIBs, the outer Fe₂O₃ shell can act as an electrochemically active material to store and release lithium ions, whereas the highly conductive and inactive Fe core functions as nothing more than an efficient electrical conducting pathway and a remarkable buffer to tolerate volume changes of the electrode materials during the insertion and extraction of lithium ions. The core–shell Fe/Fe₂O₃ nanowire maintains an excellent reversible capacity of over 767 mA h g^?1 at 500 mA g^?1 after 200 cycles with a high average Coulombic efficiency of 98.6 %. Even at 2000 mA g^?1, a stable capacity as high as 538 mA h g^?1 could be obtained. The unique composition and nanostructure of this electrode material contribute to this enhanced electrochemical performance. Due to the ease of large‐scale fabrication and superior electrochemical performance, these hybrid nanowires are promising anode materials for the next generation of high‐performance LIBs.     

花瓣状微球MoS2/石墨烯复合材料的制备及其电化学性能

采用有利于二维层状结构形成的L-半胱氨酸作为硫源,钼酸钠作为钼源,制备聚乙烯基吡咯烷酮（PVP）辅助水热合成花瓣状微球形貌的MoS₂/还原氧化石墨烯复合电极材料（PVP-MoS₂/RGO）. X射线衍射（XRD）及透射电子显微镜（TEM）证实,经过PVP的适量添加,MoS₂有序堆垛结构的片层数目明显减少. 扫描电子显微镜（SEM）显示,添加适量PVP的MoS₂/石墨烯材料具有分散性更好的花瓣状微球形貌. 上述的少层有序堆垛结构及复合材料的良好分散性缩短了MoS₂中锂离子的嵌入/脱出路径,使其具有更高的容量、循环稳定性和倍率性能.     

Micro‐MoS2 with Excellent Reversible Sodium‐Ion Storage

Low storage capacity and poor cycling stability are the main drawbacks of the electrode materials for sodium‐ion (Na‐ion) batteries, due to the large radius of the Na ion. Here we show that micro‐structured molybdenum disulfide (MoS₂) can exhibit high storage capacity and excellent cycling and rate performances as an anode material for Na‐ion batteries by controlling its intercalation depth and optimizing the binder. The former method is to preserve the layered structure of MoS₂, whereas the latter maintains the integrity of the electrode during cycling. A reversible capacity of 90 mAh g^?1 is obtained on a potential plateau feature when less than 0.5 Na per formula unit is intercalated into micro‐MoS₂. The fully discharged electrode with sodium alginate (NaAlg) binder delivers a high reversible capacity of 420 mAh g^?1. Both cells show excellent cycling performance. These findings indicate that metal chalcogenides, for example, MoS₂, can be promising Na‐storage materials if their operation potential range and the binder can be appropriately optimized.     

MoS2-Based Catalysts for N2 Electroreduction to NH3 – An Overview of MoS2 Optimization Strategies

The nitrogen reduction reaction (NRR) has become an ideal alternative to the Haber-Bosch process, as NRR possesses, among others, the advantage of operating under ambient conditions and saving energy consumption. The key to efficient NRR is to find a suitable electrocatalyst, which helps to break the strong N≡N bond and improves the reaction selectivity. Molybdenum disulfide (MoS₂) as an emerging layered two-dimensional material has attracted a mass of attention in various fields. In this minireview, we summarize the optimization strategies of MoS₂-based catalysts which have been developed to improve the weak NRR activity of primitive MoS₂. Some theoretical predictions have also been summarized, which can provide direction for optimizing NRR activity of future MoS₂-based materials. Finally, an outlook about the optimization of MoS₂-based catalysts used in electrochemical N₂ fixation are given.     

Interlayer-expanded MoS<Subscript>2</Subscript>/graphene composites as anode materials for high-performance lithium-ion batteries

A facile strategy was developed to prepare interlayer-expanded MoS₂/graphene composites through a one-step hydrothermal reaction method. MoS₂ nanosheets with several-layer thickness were observed to uniformly grow on the surface of graphene sheets. And the interlayer spacing of MoS₂ in the composites was determined to expand to 0.95 nm by ammonium ions intercalation. The MoS₂/graphene composites show excellent lithium storage performance as anode materials for Li-ion batteries. Through gathering advantages including expanded interlayers, several-layer thickness, and composited graphene, the composites exhibit reversible capacity of 1030.6 mAh g^?1 at the current density of 100 mA g^?1 and still retain a high specific capacity of 725.7 mAh g^?1 at a higher current density of 1000 mA g^?1 after 50 cycles.     

Hybrid Structures of Sisal Fiber Derived Interconnected Carbon Nanosheets/MoS2/Polyaniline as Advanced Electrode Materials in Lithium-Ion Batteries

In this work, we designed and successfully synthesized an interconnected carbon nanosheet/MoS₂/polyaniline hybrid (ICN/MoS₂/PANI) by combining the hydrothermal method and in situ chemical oxidative polymerization. The as-synthesized ICNs/MoS₂/PANI hybrid showed a “caramel treat-like” architecture in which the sisal fiber derived ICNs were used as hosts to grow “follower-like” MoS₂ nanostructures, and the PANI film was controllably grown on the surface of ICNs and MoS₂. As a LIBs anode material, the ICN/MoS₂/PANI electrode possesses excellent cycling performance, superior rate capability, and high reversible capacity. The reversible capacity retains 583 mA h/g after 400 cycles at a high current density of 2 A/g. The standout electrochemical performance of the ICN/MoS₂/PANI electrode can be attributed to the synergistic effects of ICNs, MoS₂ nanostructures, and PANI. The ICN framework can buffer the volume change of MoS₂, facilitate electron transfer, and supply more lithium inset sites. The MoS₂ nanostructures provide superior rate capability and reversible capacity, and the PANI coating can further buffer the volume change and facilitate electron transfer.     

Bismuth Nanoparticles Anchored on Ti3C2Tx MXene Nanosheets for High-Performance Sodium-Ion Batteries

Sodium-ion batteries are promising energy-storage systems, but they are facing huge challenges for developing fast-charging anode materials. Bismuth (Bi)-based anode materials are considered as candidates for fast-charging anodes of sodium-ion batteries due to their excellent rate performance. Herein, we designed a two-dimensional Bi/MXene anode material based on a hydrogen thermal reduction strategy. Benefitting from microstructure advantages, Bi/MXene anodes exhibited an excellent rate capability and superior cycle performance in Na//Bi/MXene half-batteries and Na₃V₂(PO₄)₃/C//Bi/MXene full-batteries. Moreover, full-batteries can complete a charge/discharge cycle in 7 min and maintain an excellent cycle life (over 7000 cycles). The electrochemical test results showed that Bi/MXene is a promising anode material with fast charge/discharge capability for sodium-ion batteries.     

Improved electrode fabrication method to enhance performance and stability of MoS2-based lithium-ion battery anode

Choice of binder and the electrode-making process play a pivotal role in the electrochemical performance of MoS₂, when used as lithium-ion battery anode. In this work, MoS₂ nanorods are prepared by gas phase synthesis method using molybdenum trioxide (MoO₃) nanobelts and sulfur as starting materials. It has been observed that by tuning the reaction conditions, morphology and yield of the final product can be controlled. Carboxymethyl cellulose (CMC) is used as binder to fabricate the MoS₂ electrode, and its electrochemical performance is tested against Li/Li⁺. The performance of electrode can be further improved by incorporating heat treatment to the active material and conductive carbon mixture prior to electrode fabrication. The electrochemical data shows that the optimum temperature for heat treatment is 700 °C. In the current report, we would like to elucidate a detailed study based on electrode fabrication process and their impact on the electrochemical performance.     

Three‐Dimensional Fe2N@C Microspheres Grown on Reduced Graphite Oxide for Lithium‐Ion Batteries and the Li Storage Mechanism

Nanostructured iron compounds as lithium‐ion‐battery anode material have attracted considerable attention with respect to improved electrochemical energy storage and excellent specific capacity, so lots of iron‐based composites have been developed. Herein, a novel composite composed of three‐dimensional Fe₂N@C microspheres grown on reduced graphite oxide (denoted as Fe₂N@C‐RGO) has been synthesized through a simple and effective technique assisted by a hydrothermal and subsequent heating treatment process. As the anode material for lithium‐ion batteries, the synthetic Fe₂N@C‐RGO displayed excellent Li⁺‐ion storage performance with a considerable initial capacity of 847 mAh g^?1, a superior cycle stability (a specific discharge capacity of 760 mAh g^?1 remained after the 100th cycle), and an improved rate‐capability performance compared with those of the pure Fe₂N and Fe₂N‐RGO nanostructures. The good performance should be attributed to the existence of RGO layers that can facilitate to enhance the conductivity and shorten the lithium‐ion diffusion path; in addition, the carbon layer on the surface of Fe₂N can avert the structure decay caused by the volume change during the lithiation/delithiation process. Moreover, in situ X‐ray absorption fine‐structure analysis demonstrated that the excellent performance can be attributed to the lack of any obvious change in the coordination geometry of Fe₂N@C‐RGO during the charge/discharge processes.     

Fe2O3锂离子电池负极材料研究进展

Fe2O3锂离子电池负极材料因其具有的高能量密度而备受关注。但Fe2O3电极材料存在的如低导电性、充/放电过程中体积改变导致的循环稳定性差等问题限制其实际应用。介绍了高比表面积、结构稳定以及储锂动力学等因素对锂离子电池负极材料电化学性能的重要影响,综述电极活性材料纳米化、形貌控制和杂原子掺杂对Fe2O3负极材料电化学性能改善的相关研究进展,最后对Fe2O3电极材料的发展前景进行了展望。