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1.
Sodium‐ion batteries (SIBs) are regarded as the best alternative to lithium‐ion batteries due to their low cost and similar Na+ insertion chemistry. It is still challenging but greatly desired to design and develop novel electrode materials with high reversible capacity, long cycling life, and good rate capability toward high‐performance SIBs. This work demonstrates an innovative design strategy and a development of few‐layered molybdenum disulfide/sulfur‐doped graphene nanosheets (MoS2/SG) composites as the SIB anode material providing a high specific capacity of 587 mA h g?1 calculated based on the total composite mass and an extremely long cycling stability over 1000 cycles at a current density of 1.0 A g?1 with a high capacity retention of ≈85%. Systematic characterizations reveal that the outstanding performance is mainly attributed to the unique and robust composite architecture where few‐layered MoS2 and S‐doped graphene are intimately bridged at the hetero‐interface through a synergistic coupling effect via the covalently doped S atoms. The design strategy and mechanism understanding at the molecular level outlined here can be readily applied to other layered transition metal oxides for SIBs anode and play a key role in contributing to the development of high‐performance SIBs.  相似文献   

2.
Sodium‐ion batteries (SIBs) are considered as a promising alternative to lithium‐ion batteries, due to the abundant reserves and low price of Na sources. To date, the development of anode materials for SIBs is still confronted with many serious problems. In this work, encapsulation‐type structured MoSe2@hollow carbon nanosphere (HCNS) materials assembled with expanded (002) planes few‐layer MoSe2 nanosheets confined in HCNS are successfully synthesized through a facile strategy. Notably, the interlayer spacing of the (002) planes is expanded to 1.02 nm, which is larger than the intrinsic value of pristine MoSe2 (0.64 nm). Furthermore, the few‐layer nanosheets are space‐confined in the inner cavity of the HCNS, forming hybrid MoSe2@HCNS structures. When evaluated as anode materials for SIBs, it shows excellent rate capabilities, ultralong cycling life with exceptional Coulombic efficiency even at high current density, maintaining 501 and 471 mA h g?1 over 1000 cycles at 1 and 3 A g?1, respectively. Even when cycled at current densities as high as 10 A g?1, a capacity retention of 382 mA h g?1 can be achieved. The expanded (002) planes, 2D few‐layer nanosheets, and unique carbon shell structure are responsible for the ultralong cycling and high rate performance.  相似文献   

3.
To tackle the issue of inferior cycle stability and rate capability for MnO anode materials in lithium ion batteries, a facile strategy is explored to prepare a hybrid material consisting of MnO nanocrystals grown on conductive graphene nanosheets. The prepared MnO/graphene hybrid anode exhibits a reversible capacity as high as 2014.1 mAh g?1 after 150 discharge/charge cycles at 200 mA g?1, excellent rate capability (625.8 mAh g?1 at 3000 mA g?1), and superior cyclability (843.3 mAh g?1 even after 400 discharge/charge cycles at 2000 mA g?1 with only 0.01% capacity loss per cycle). The results suggest that the reconstruction of the MnO/graphene electrodes is intrinsic due to conversion reactions. A long‐term stable nanoarchitecture of graphene‐supported ultrafine manganese oxide nanoparticles is formed upon cycling, which yields a long‐life anode material for lithium ion batteries. The lithiation and delithiation behavior suggests that the further oxidation of Mn(II ) to Mn(IV ) and the interfacial lithium storage upon cycling contribute to the enhanced specific capacity. The excellent rate capability benefits from the presence of conductive graphene and a short transportation length for both lithium ions and electrons. Moreover, the as‐formed hybrid nanostructure of MnO on graphene may help achieve faster kinetics of conversion reactions.  相似文献   

4.
With the increasing demand for low cost, long lifetime, high energy density storage systems, an extensive amount of effort has recently been focused on the development of sodium‐ion batteries (SIBs), and a variety of cathode materials have been discovered. However, looking for the most suitable anode material for practical application is a major challenge for SIBs. Herein, a high capacity sulfur‐doped black phosphorus‐TiO2 (TiO2‐BP‐S) anode material for SIBs is first synthesized by a feasible and large‐scale high‐energy ball‐milling approach, and its stability in air exposure is investigated through X‐ray photoelectron spectroscopy. The morphology of TiO2‐BP‐S is characterized using transmission electron microscopy, indicating that the TiO2 nanoparticles produce P? Ti bonds with BP. The TiO2‐BP‐S composite with P? S and P? Ti bonds exhibits excellent stability in air and the superior electrochemical performance. For example, the discharge specific capacity is up to 490 mA h g?1 after 100 cycles at 50 mA g?1, and it remains at 290 mA h g?1 after 600 cycles at 500 mA g?1. Meanwhile, the scientific insight that the formation of stable P? S and P? Ti bonds can provide a guide for the practical large‐scale application of SIBs in other titanium base and black phosphorus materials is looked forward.  相似文献   

5.
Sodium ion batteries (SIBs) are a promising alternative to lithium ion batteries for a broader range of energy storage applications in the future. However, the development of high‐performance anode materials is a bottleneck of SIBs advancement. In this work, Sb2Se3 nanorods uniformly wrapped by reduced graphene oxide (rGO) as a promising anode material for SIBs are reported. The results show that such Sb2Se3/rGO hybrid anode yields a high reversible mass‐specific energy capacity of 682, 448, and 386 mAh g?1 at a rate of 0.1, 1.0, and 2.0 A g?1, respectively, and sustains at least 500 stable cycles at a rate of 1.0 A g?1 with an average mass‐specific energy capacity of 417 mAh g?1 and capacity retention of 90.2%. In situ X‐ray diffraction study on a live SIB cell reveals that the observed high performance is a result of the combined Na+ intercalation, conversion reaction between Na+ and Se, and alloying reaction between Na+ and Sb. The presence of rGO also plays a key role in achieving high rate capacity and cycle stability by providing good electrical conductivity, tolerant accommodation to volume change, and strong electron interactions to the base Sb2Se3 anode.  相似文献   

6.
Germanium is considered as a promising anode material because of its comparable lithium and sodium storage capability, but it usually exhibits poor cycling stability due to the large volume variation during lithium or sodium uptake and release processes. In this paper, germanium@graphene nanofibers are first obtained through electrospinning followed by calcination. Then atomic layer deposition is used to fabricate germanium@graphene@TiO2 core–shell nanofibers (Ge@G@TiO2 NFs) as anode materials for lithium and sodium ion batteries (LIBs and SIBs). Graphene and TiO2 can double protect the germanium nanofibers in charge and discharge processes. The Ge@G@TiO2 NFs composite as an anode material is versatile and exhibits enhanced electrochemical performance for LIBs and SIBs. The capacity of the Ge@G@TiO2 NFs composite can be maintained at 1050 mA h g?1 (100th cycle) and 182 mA h g?1 (250th cycle) for LIBs and SIBs, respectively, at a current density of 100 mA g?1, showing high capacity and good cycling stability (much better than that of Ge nanofibers or Ge@G nanofibers).  相似文献   

7.
Na‐ion Batteries have been considered as promising alternatives to Li‐ion batteries due to the natural abundance of sodium resources. Searching for high‐performance anode materials currently becomes a hot topic and also a great challenge for developing Na‐ion batteries. In this work, a novel hybrid anode is synthesized consisting of ultrafine, few‐layered SnS2 anchored on few‐layered reduced graphene oxide (rGO) by a facile solvothermal route. The SnS2/rGO hybrid exhibits a high capacity, ultralong cycle life, and superior rate capability. The hybrid can deliver a high charge capacity of 649 mAh g?1 at 100 mA g?1. At 800 mA g?1 (1.8 C), it can yield an initial charge capacity of 469 mAh g?1, which can be maintained at 89% and 61%, respectively, after 400 and 1000 cycles. The hybrid can also sustain a current density up to 12.8 A g?1 (≈28 C) where the charge process can be completed in only 1.3 min while still delivering a charge capacity of 337 mAh g?1. The fast and stable Na‐storage ability of SnS2/rGO makes it a promising anode for Na‐ion batteries.  相似文献   

8.
Carbon‐based materials are promising anodes for potassium‐ion batteries (PIBs). However, due to the significant volume expansion and structural instability, it is still a challenge to achieve a high capacity, high rate and long cycle life for carbonaceous anodes. Herein, oxygen/fluorine dual‐doped porous carbon nanopolyhedra (OFPCN) is reported for the first time as a novel anode for PIBs, which exhibits a high reversible capacity of 481 mA h g?1 at 0.05 A g?1 and excellent performance of 218 mA h g?1 after 2000 cycles at 1 A g?1 with 92% capacity retention. Even after 5000 robust cycles at 10 A g?1 with charging/discharging time of around 40 s, an unprecedented capacity of 111 mA h g?1 is still maintained. Such ultrafast potassium storage and unprecedented cycling stability have been seldom reported in PIBs. Quantitative kinetics analysis reveals that both diffusion and capacitance processes are involved in the potassium storage mechanism. Density functional theory calculations demonstrate that the O/F dual‐doped porous carbon promotes the K‐adsorption ability and can absorb multiple K atoms with slight structural distortion, which accounts for the high specific capacity, outstanding rate capability, and excellent cycling stability of the OFPCN anode.  相似文献   

9.
Hard carbon (HC) is a promising anode material for sodium‐ion batteries (SIBs) and potassium‐ion batteries (PIBs), but the volume change during the insertion/extraction of Na+ or K+ limits the cycle life, especially for PIBs due to the large ion size of K+. Moreover, the conventional anodes fabricated through the coating method cannot satisfy the requirement of flexible devices. Here, it is shown that 2D carbide flakes of Ti3C2Tx MXene can be used as multifunctional conductive binders for flexible HC electrodes. The use of MXene nanosheets eliminates the need for all the electrochemically inactive components in the conventional polyvinylidene fluoride–bonded HC electrode, including polymer binders, conductive additives, and current collectors. In MXene‐bonded HC electrodes, conductive and hydrophilic MXene 2D nanosheets construct a 3D network, which can effectively stabilize the electrode structure and accommodate the volume expansion of HC during the charge/discharge process, leading to an enhanced electrode capacity and excellent cycle performance as anodes for both SIBs and PIBs. Benefiting from the 3D conductive network, the MXene‐bonded HC film electrodes also present improved rate capability, indicating MXene is a very promising multifunctional binder for next‐generation flexible secondary rechargeable batteries.  相似文献   

10.
This work studies for the first time the metallic 1T MoS2 sandwich grown on graphene tube as a freestanding intercalation anode for promising sodium‐ion batteries (SIBs). Sodium is earth‐abundant and readily accessible. Compared to lithium, the main challenge of sodium‐ion batteries is its sluggish ion diffusion kinetic. The freestanding, porous, hollow structure of the electrode allows maximum electrolyte accessibility to benefit the transportation of Na+ ions. Meanwhile, the metallic MoS2 provides excellent electron conductivity. The obtained 1T MoS2 electrode exhibits excellent electrochemical performance: a high reversible capacity of 313 mAh g?1 at a current density of 0.05 A g?1 after 200 cycles and a high rate capability of 175 mAh g?1 at 2 A g?1. The underlying mechanism of high rate performance of 1T MoS2 for SIBs is the high electrical conductivity and excellent ion accessibility. This study sheds light on using the 1T MoS2 as a novel anode for SIBs.  相似文献   

11.
Potassium‐ion batteries (PIBs) are currently drawing increased attention as a promising alternative to lithium‐ion batteries (LIBs) owing to the abundant resource and low cost of potassium. However, due to the large ionic radius size of K+, electrode material that can stably maintain K+ insertion/deintercalation is still extremely inadequate, especially for anode material with a satisfactory reversible capacity. As an attempt, nitrogen/carbon dual‐doped hierarchical NiS2 is introduced as the electrode material in PIBs for the first time. Considering that the introduction of the carbon layer effectively alleviates the volume expansion of the material itself, further improves the electronic conductivity, and finally accelerates the charge transfer of K+, not surprisingly, NiS2 decorated with the bifunctional carbon (NiS2@C@C) material electrode shows excellent potassium storage performances. When utilized as a PIB anode, it delivers a high reversible capacity of 302.7 mAh g?1 at 50 mA g?1 after 100 cycles. The first coulombic efficiency is 78.6% and rate performance is 151.2 mAh g?1 at 1.6 A g?1 of the NiS2@C@C, which are also notable. Given such remarkable electrochemical properties, this work is expected to provide more possibilities for the reasonable design of advanced electrode materials for metal sulfide potassium ion batteries.  相似文献   

12.
To develop high‐performance anode materials of lithium‐ion batteries (LIBs) instead of commercial graphite for practical applications, herein, a layer of silicon has been well‐anchored onto a 3D graphene/carbon nanotube (CNT) aerogels (CAs) framework with face‐to‐face contact and balanced open void by a simple chemical vapor deposition strategy. The engineered contact interface between CAs and Si creates high‐efficiency channels for the rapid electrons and lithium ions transport, and meanwhile, the balanced open‐void allows the free expansion of Si during cycling while maintaining high structural integrity due to the robust mechanical strength of 3D CAs framework. As a consequence, the as‐synthesized Si/CAs nanohybrids are highly stable anode materials for LIBs with a high reversible discharge capacity (1498 mAh g?1 at 200 mA g?1) and excellent rate capability (462 mAh g?1 at 10 000 mA g?1), which is much better than Si/graphene‐CNTs‐mixture (51 mAh g?1 at 10 000 mA g?1). More significantly, it is found that the Si/CAs nanohybrids display no obvious capacity decline even after 2000 cycles at a high current density of 10 000 mA g?1. The present Si/CAs nanohybrids are one of the most stable Si‐based anode materials ever reported for LIBs to date.  相似文献   

13.
On account of increasing demand for energy storage devices, sodium‐ion batteries (SIBs) with abundant reserve, low cost, and similar electrochemical properties have the potential to partly replace the commercial lithium‐ion batteries. In this study, a facile metal‐organic framework (MOF)‐derived selenidation strategy to synthesize in situ carbon‐encapsulated selenides as superior anode for SIBs is rationally designed. These selenides with particular micro‐ and nanostructured features deliver ultrastable cycling performance at high charge–discharge rate and demonstrate ultraexcellent rate capability. For example, the uniform peapod‐like Fe7Se8@C nanorods represent a high specific capacity of 218 mAh g?1 after 500 cycles at 3 A g?1 and the porous NiSe@C spheres display a high specific capacity of 160 mAh g?1 after 2000 cycles at 3 A g?1. The current simple MOF‐derived method could be a promising strategy for boosting the development of new functional inorganic materials for energy storage, catalysis, and sensors.  相似文献   

14.
Flexible freestanding electrodes are highly desired to realize wearable/flexible batteries as required for the design and production of flexible electronic devices. Here, the excellent electrochemical performance and inherent flexibility of atomically thin 2D MoS2 along with the self‐assembly properties of liquid crystalline graphene oxide (LCGO) dispersion are exploited to fabricate a porous anode for high‐performance lithium ion batteries. Flexible, free‐standing MoS2–reduced graphene oxide (MG) film with a 3D porous structure is fabricated via a facile spontaneous self‐assembly process and subsequent freeze‐drying. This is the first report of a one‐pot self‐assembly, gelation, and subsequent reduction of MoS2/LCGO composite to form a flexible, high performance electrode for charge storage. The gelation process occurs directly in the mixed dispersion of MoS2 and LCGO nanosheets at a low temperature (70 °C) and normal atmosphere (1 atm). The MG film with 75 wt% of MoS2 exhibits a high reversible capacity of 800 mAh g?1 at a current density of 100 mA g?1. It also demonstrates excellent rate capability, and excellent cycling stability with no capacity drop over 500 charge/discharge cycles at a current density of 400 mA g?1.  相似文献   

15.
The high theoretical capacity and natural abundance of SiO2 make it a promising high‐capacity anode material for lithium‐ion batteries. However, its widespread application is significantly hampered by the intrinsic poor electronic conductivity and drastic volume variation. Herein, a unique hollow structured Ni/SiO2 nanocomposite constructed by ultrafine Ni nanoparticle (≈3 nm) functionalized SiO2 nanosheets is designed. The Ni nanoparticles boost not only the electronic conductivity but also the electrochemical activity of SiO2 effectively. Meanwhile, the hollow cavity provides sufficient free space to accommodate the volume change of SiO2 during repeated lithiation/delithiation; the nanosheet building blocks reduce the diffusion lengths of lithium ions. Due to the synergistic effect between Ni and SiO2, the Ni/SiO2 composite delivers a high reversible capacity of 676 mA h g?1 at 0.1 A g?1. At a high current density of 10 A g?1, a capacity of 337 mA h g?1 can be retained after 1000 cycles.  相似文献   

16.
Heterostructuring electrodes with multiple electroactive and inactive supporting components to simultaneously satisfy electrochemical and structural requirements has recently been identified as a viable pathway to achieve high‐capacity and durable sodium‐ion batteries (SIBs). Here, a new design of heterostructured SIB anode is reported consisting of double metal‐sulfide (SnCo)S2 nanocubes interlaced with 2D sulfur‐doped graphene (SG) nanosheets. The heterostructured (SnCo)S2/SG nanocubes exhibit an excellent rate capability (469 mAh g?1 at 10.0 A g?1) and durability (5000 cycles, 487 mAh g?1 at 5.0 A g?1, 92.6% capacity retention). In situ X‐ray diffraction reveals that the (SnCo)S2/SG anode undergoes a six‐stage Na+ storage mechanism of combined intercalation, conversion, and alloying reactions. The first‐principle density functional theory calculations suggest high concentration of p–n heterojunctions at SnS2/CoS2 interfaces responsible for the high rate performance, while in situ transmission electron microscopy unveils that the interlacing and elastic SG nanosheets play a key role in extending the cycle life.  相似文献   

17.
Sodium‐ion batteries have recently attracted intensive attention due to their natural abundance and low cost. Antimony is a desirable candidate for an anode material for sodium‐ion batteries due to its high theoretical capacity (660 mA h g?1). However, the utilization of alloy‐based anodes is still limited by their inherent huge volume changes and sluggish kinetics. The Sb‐embedded silicon oxycarbide (SiOC) composites are simply synthesized via a one‐pot pyrolysis process at 900 °C without any additives or surfactants, taking advantage of the superior self‐dispersion properties of antimony acetate powders in silicone oil. The structural and morphological characterizations confirm that Sb nanoparticles are homogeneously embedded into the amorphous SiOC matrix. The composite materials exhibit an initial desodiation capacity of around 510 mA h g?1 and maintained an excellent capacity retention above 97% after 250 cycles. The rate capability test reveals that the composites deliver capacity greater than 453 mA h g?1, even at the high current density of 20 C rate, owing to the free‐carbon domain of SiOC material. The electrochemical and postmortem analyses confirm that the SiOC matrix with a uniform distribution of Sb nanoparticles provides the mechanical strength without degradation in conductive characteristics, suppressing the agglomeration of Sb particles during the electrochemical reaction.  相似文献   

18.
Tin oxide‐based materials attract increasing attention as anodes in lithium‐ion batteries due to their high theoretical capacity, low cost, and high abundance. Composites of such materials with a carbonaceous matrix such as graphene are particularly promising, as they can overcome the limitations of the individual materials. The fabrication of antimony‐doped tin oxide (ATO)/graphene hybrid nanocomposites is described with high reversible capacity and superior rate performance using a microwave assisted in situ synthesis in tert‐butyl alcohol. This reaction enables the growth of ultrasmall ATO nanoparticles with sizes below 3 nm on the surface of graphene, providing a composite anode material with a high electric conductivity and high structural stability. Antimony doping results in greatly increased lithium insertion rates of this conversion‐type anode and an improved cycling stability, presumably due to the increased electrical conductivity. The uniform composites feature gravimetric capacity of 1226 mAh g?1 at the charging rate 1C and still a high capacity of 577 mAh g?1 at very high charging rates of up to 60C, as compared to 93 mAh g?1 at 60C for the undoped composite synthesized in a similar way. At the same time, the antimony‐doped anodes demonstrate excellent stability with a capacity retention of 77% after 1000 cycles.  相似文献   

19.
3D graphene, as a light substrate for active loadings, is essential to achieve high energy density for aqueous Zn‐ion batteries, yet traditional synthesis routes are inefficient with high energy consumption. Reported here is a simplified procedure to transform the raw graphite paper directly into the graphene‐like carbon film (GCF). The electrochemically derived GCF contains a 2D–3D hybrid network with interconnected graphene sheets, and offers a highly porous structure. To realize high energy density, the Na:MnO2/GCF cathode and Zn/GCF anode are fabricated by electrochemical deposition. The GCF‐based Zn‐ion batteries deliver a high initial discharge capacity of 381.8 mA h g?1 at 100 mA g?1 and a reversible capacity of 188.0 mA h g?1 after 1000 cycles at 1000 mA g?1. Moreover, a recorded energy density of 511.9 Wh kg?1 is obtained at a power density of 137 W kg?1. The electrochemical kinetics measurement reveals the high capacitive contribution of the GCF and a co‐insertion/desertion mechanism of H+ and Zn2+ ions. First‐principles calculations are also carried out to investigate the effect of Na+ doping on the electrochemical performance of layered δ‐MnO2 cathodes. The results demonstrate the attractive potential of the GCF substrate in the application of the rechargeable batteries.  相似文献   

20.
Metal oxide‐based nanomaterials are widely studied because of their high‐energy densities as anode materials in lithium‐ion batteries. However, the fast capacity degradation resulting from the large volume expansion upon lithiation hinders their practical application. In this work, the preparation of walnut‐like multicore–shell MnO encapsulated nitrogen‐rich carbon nanocapsules (MnO@NC) is reported via a facile and eco‐friendly process for long‐cycling Li‐ion batteries. In this hybrid structure, MnO nanoparticles are uniformly dispersed inside carbon nanoshells, which can simultaneously act as a conductive framework and also a protective buffer layer to restrain the volume variation. The MnO@NC nanocapsules show remarkable electrochemical performances for lithium‐ion batteries, exhibiting high reversible capability (762 mAh g?1 at 100 mA g?1) and stable cycling life (624 mAh g?1 after 1000 cycles at 1000 mA g?1). In addition, the soft‐packed full batteries based on MnO@NC nanocapsules anodes and commercial LiFePO4 cathodes present good flexibility and cycling stability.  相似文献   

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