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1.
Alloy anodes have shown great potential for next‐generation lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs). However, these applications are still limited by inherent huge volume changes and sluggish kinetics. To overcome such limitations, graphene‐protected 3D Sb‐based anodes grown on conductive substrate are designed and fabricated by a facile electrostatic‐assembling and subsequent confinement replacement strategy. As binder‐free anodes for LIBs, the obtained electrode exhibits reversible capacities of 442 mAh g−1 at 100 mA g−1 and 295 mAh g−1 at 1000 mA g−1, and a capacity retention of above 90% (based on the 10th cycle) after 200 cycles at 500 mA g−1. As for sodium storage properties, the reversible capacities of 517 mAh g−1 at 50 mA g−1 and 315 mAh g−1 at 1000 mA g−1, the capacity retention of 305 mAh g−1 after 100 cycles at 300 mA g−1 are obtained, respectively. Furthermore, the 3D architecture retains good structural integrity after cycling, confirming that the introduction of high‐stretchy and robust graphene layers can effectively buffer alloying anodes, and simultaneously provide sustainable contact and protection of the active materials. Such findings show its great potential as superior binder‐free anodes for LIBs and SIBs.  相似文献   

2.
2D Sulfur‐doped TiSe2/Fe3O4 (named as S‐TiSe2/Fe3O4) heterostructures are synthesized successfully based on a facile oil phase process. The Fe3O4 nanoparticles, with an average size of 8 nm, grow uniformly on the surface of S‐doped TiSe2 (named as S‐TiSe2) nanoplates (300 nm in diameter and 15 nm in thickness). These heterostructures combine the advantages of both S‐TiSe2 with good electrical conductivity and Fe3O4 with high theoretical Li storage capacity. As demonstrated potential applications for energy storage, the S‐TiSe2/Fe3O4 heterostructures possess high reversible capacities (707.4 mAh g−1 at 0.1 A g−1 during the 100th cycle), excellent cycling stability (432.3 mAh g−1 after 200 cycles at 5 A g−1), and good rate capability (e.g., 301.7 mAh g−1 at 20 A g−1) in lithium‐ion batteries. As for sodium‐ion batteries, the S‐TiSe2/Fe3O4 heterostructures also maintain reversible capacities of 402.3 mAh g−1 at 0.1 A g−1 after 100 cycles, and a high rate capacity of 203.3 mAh g−1 at 4 A g−1.  相似文献   

3.
Sodium‐ion batteries (SIBs) are promising energy storage devices, but suffer from poor cycling stability and low rate capability. In this work, carbon doped Mo(Se0.85S0.15)2 (i.e., Mo(Se0.85S0.15)2:C) hierarchical nanotubes have been synthesized for the first time and serve as a robust and high‐performance anode material. The hierarchical nanotubes with diameters of 300 nm and wall thicknesses of 50 nm consist of numerous 2D layered nanosheets, and can act as a robust host for sodiation/desodiation cycling. The Mo(Se0.85S0.15)2:C hierarchical nanotubes deliver a discharge capacity of 360 mAh g−1 at a high current density of 2000 mA g−1 and keep a 81.8% capacity retention compared to that at a current density of 50 mA g−1, showing superior rate capability. Comparing with the second cycle discharge capacities, the nanotube anode can maintain capacities of 102.2%, 101.9%, and 97.8% after 100 cycles at current densities of 200, 500, and 1000 mA g−1, respectively. This work demonstrates the best cycling performance and high‐rate sodium storage capabilities of MoSe2 for SIBs to date. The hollow interior, hierarchical organization, layered structure, and carbon doping are beneficial for fast Na+‐ion and electron kinetics and are responsible for the stable cycling performance and high rate capabilities.  相似文献   

4.
The ingenious design of a freestanding flexible electrode brings the possibility for power sources in emerging wearable electronic devices. Here, reduced graphene oxide (rGO) wraps carbon nanotubes (CNTs) and rGO tightly surrounded by MnO2 nanosheets, forming a 3D multilevel porous conductive structure via vacuum freeze‐drying. The sandwich‐like architecture possesses multiple functions as a flexible anode for lithium‐ion batteries. Micrometer‐sized pores among the continuously waved rGO layers could extraordinarily improve ion diffusion. Nano‐sized pores among the MnO2 nanosheets and CNT/rGO@MnO2 particles could provide vast accessible active sites and alleviate volume change. The tight connection between MnO2 and carbon skeleton could facilitate electron transportation and enhance structural stability. Due to the special structure, the rGO‐wrapped CNT/rGO@MnO2 porous film as an anode shows a high capacity, excellent rate performance, and superior cycling stability (1344.2 mAh g−1 over 630 cycles at 2 A g−1, 608.5 mAh g−1 over 1000 cycles at 7.5 A g−1). Furthermore, the evolutions of microstructure and chemical valence occurring inside the electrode after cycling are investigated to illuminate the structural superiority for energy storage. The excellent electrochemical performance of this freestanding flexible electrode makes it an attractive candidate for practical application in flexible energy storage.  相似文献   

5.
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 Co0.85Se1?xSx 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.  相似文献   

6.
Inspired by its high‐active and open layered framework for fast Li+ extraction/insertion reactions, layered Ni‐rich oxide is proposed as an outstanding Na‐intercalated cathode for high‐performance sodium‐ion batteries. An O3‐type Na0.75Ni0.82Co0.12Mn0.06O2 is achieved through a facile electrochemical ion‐exchange strategy in which Li+ ions are first extracted from the LiNi0.82Co0.12Mn0.06O2 cathode and Na+ ions are then inserted into a layered oxide framework. Furthermore, the reaction mechanism of layered Ni‐rich oxide during Na+ extraction/insertion is investigated in detail by combining ex situ X‐ray diffraction, X‐ray photoelectron spectroscopy, and electron energy loss spectroscopy. As an excellent cathode for Na‐ion batteries, O3‐type Na0.75Ni0.82Co0.12Mn0.06O2 delivers a high reversible capacity of 171 mAh g?1 and a remarkably stable discharge voltage of 2.8 V during long‐term cycling. In addition, the fast Na+ transport in the cathode enables high rate capability with 89 mAh g?1 at 9 C. The as‐prepared Ni‐rich oxide cathode is expected to significantly break through the limited performance of current sodium‐ion batteries.  相似文献   

7.
A high capacity cathode is the key to the realization of high‐energy‐density lithium‐ion batteries. The anionic oxygen redox induced by activation of the Li2MnO3 domain has previously afforded an O3‐type layered Li‐rich material used as the cathode for lithium‐ion batteries with a notably high capacity of 250–300 mAh g?1. However, its practical application in lithium‐ion batteries has been limited due to electrodes made from this material suffering severe voltage fading and capacity decay during cycling. Here, it is shown that an O2‐type Li‐rich material with a single‐layer Li2MnO3 superstructure can deliver an extraordinary reversible capacity of 400 mAh g?1 (energy density: ≈1360 Wh kg?1). The activation of a single‐layer Li2MnO3 enables stable anionic oxygen redox reactions and leads to a highly reversible charge–discharge cycle. Understanding the high performance will further the development of high‐capacity cathode materials that utilize anionic oxygen redox processes.  相似文献   

8.
Potassium‐ion batteries (PIBs) are one of the emerging energy‐storage technologies due to the low cost of potassium and theoretically high energy density. However, the development of PIBs is hindered by the poor K+ transport kinetics and the structural instability of the cathode materials during K+ intercalation/deintercalation. In this work, birnessite nanosheet arrays with high K content (K0.77MnO2?0.23H2O) are prepared by “hydrothermal potassiation” as a potential cathode for PIBs, demonstrating ultrahigh reversible specific capacity of about 134 mAh g?1 at a current density of 100 mA g?1, as well as great rate capability (77 mAh g?1 at 1000 mA g?1) and superior cycling stability (80.5% capacity retention after 1000 cycles at 1000 mA g?1). With the introduction of adequate K+ ions in the interlayer, the K‐birnessite exhibits highly stabilized layered structure with highly reversible structure variation upon K+ intercalation/deintercalation. The practical feasibility of the K‐birnessite cathode in PIBs is further demonstrated by constructing full cells with a hard–soft composite carbon anode. This study highlights effective K+‐intercalation for birnessite to achieve superior K‐storage performance for PIBs, making it a general strategy for developing high‐performance cathodes in rechargeable batteries beyond lithium‐ion batteries.  相似文献   

9.
Owing to the low‐cost, safety, dendrite‐free formation, and two‐electron redox properties of magnesium (Mg), rechargeable Mg batteries are considered as promising next‐generation secondary batteries with high specific capacity and energy density. However, the clumsy Mg2+ with high polarity inclines to sluggish Mg insertion/deinsertion, leading to inadequate reversible capacity and rate performance. Herein, 2D VOPO4 nanosheets with expanded interlayer spacing (1.42 nm) are prepared and applied in rechargeable magnesium batteries for the first time. The interlayer expansion provides enough diffusion space for fast kinetics of MgCl+ ion flux with low polarization. Benefiting from the structural configuration, the Mg battery exhibits a remarkable reversible capacity of 310 mAh g?1 at 50 mA g?1, excellent rate capability, and good cycling stability (192 mAh g?1 at 100 mA g?1 even after 500 cycles). In addition, density functional theory (DFT) computations are conducted to understand the electrode behavior with decreased MgCl+ migration energy barrier compared with Mg2+. This approach, based on the regulation of interlayer distance to control cation insertion, represents a promising guideline for electrode material design on the development of advanced secondary multivalent‐ion batteries.  相似文献   

10.
A mild and environmental‐friendly method is developed for fabricating a 3D interconnected graphene electrode with large‐scale continuity. Such material has interlayer pores between reduced graphene oxide nanosheets and in‐plane pores. Hence, a specific surface area up to 835 m2 g−1 and a high powder conductivity up to 400 S m−1 are achieved. For electrochemical applications, the interlayer pores can serve as “ion‐buffering reservoirs” while in‐plane ones act as “channels” for shortening the mass cross‐plane diffusion length, reducing the ion response time, and prevent the interlayer restacking. As binder‐free supercapacitor electrode, it delivers a specific capacitance up to 169 F g−1 with surface‐normalized capacitance close to 21 μF cm−2 (intrinsic capacitance) and power density up to 7.5 kW kg−1, in 6 m KOH aqueous electrolyte. In the case of lithium‐ion battery anode, it shows remarkable advantages in terms of the initiate reversible Coulombic efficiency (61.3%), high specific capacity (932 mAh g−1 at 100 mA g−1), and robust long‐term retention (93.5% after 600 cycles at 2000 mAh g−1).  相似文献   

11.
High energy density is the major demand for next‐generation rechargeable batteries, while the intrinsic low alkali metal adsorption of traditional carbon–based electrode remains the main challenge. Here, the mechanochemical route is proposed to prepare nitrogen doped γ‐graphyne (NGY) and its high capacity is demonstrated in lithium (LIBs)/sodium (SIBs) ion batteries. The sample delivers large reversible Li (1037 mAh g?1) and Na (570.4 mAh g?1) storage capacities at 100 mA g?1 and presents excellent rate capabilities (526 mAh g?1 for LIBs and 180.2 mAh g?1 for SIBs) at 5 A g?1. The superior Li/Na storage mechanisms of NGY are revealed by its 2D morphology evolution, quantitative kinetics, and theoretical calculations. The effects on the diffusion barriers (Eb) and adsorption energies (Ead) of Li/Na atoms in NGY are also studied and imine‐N is demonstrated to be the ideal doping format to enhance the Li/Na storage performance. Besides, the Li/Na adsorption routes in NGY are optimized according to the experimental and the first‐principles calculation results. This work provides a facile way to fabricate high capacity electrodes in LIBs/SIBs, which is also instructive for the design of other heteroatomic doped electrodes.  相似文献   

12.
Homogeneous ultrasmall T‐Nb2O5 nanocrystallites encapsulated in 1D carbon nanofibers (T‐Nb2O5/CNFs) are prepared through electrospinning followed by subsequent pyrolysis treatment. In a Na half‐cell configuration, the obtained T‐Nb2O5/CNFs with the merits of unique microstructures and inherent pseudocapacitance, deliver a stable capacity of 150 mAh g−1 at 1 A g−1 over 5000 cycles. Even at an ultrahigh charge–discharge rate of 8 A g−1, a high reversible capacity of 97 mAh g−1 is still achieved. By means of kinetic analysis, it is demonstrated that the larger ratio of surface Faradaic reactions of Nb2O5 at high rates is the major factor to achieve excellent rate performance. The prolonged cycle durability and excellent rate performance endows T‐Nb2O5/CNFs with potentials as anode materials for sodium‐ion batteries.  相似文献   

13.
Tin (Sn) is considered to be an ideal candidate for the anode of sodium ion batteries. However, the design of Sn‐based electrodes with maintained long‐term stability still remains challenging due to their huge volume expansion (≈420%) and easy pulverization during cycling. Herein, a facile and versatile strategy for the synthesis of nitrogen‐doped graphene quantum dot (GQD) edge‐anchored Sn nanodots as the pillars into reduced graphene oxide blocks (NGQD/Sn‐NG) for ultrafast and ultrastable sodium‐ion storage is reported. Sn nanodots (2–5 nm) anchored at the edges of “octopus‐like” GQDs via covalent Sn? O? C/Sn? N? C bonds function as the pillars that ensure fast Na‐ion/electron transport across the graphene blocks. Moreover, the chemical and spatial (layered structure) confinements not only suppress Sn aggregation, but also function as physical barriers for buffering volume change upon sodiation/desodiation. Consequently, the NGQD/Sn‐NG with high structural stability exhibits excellent rate performance (555 mAh g?1 at 0.1 A g?1 and 198 mAh g?1 at 10 A g?1) and ultra‐long cycling stability (184 mAh g?1 remaining even after 2000 cycles at 5 A g?1). The confinement‐induced synthesis together with remarkable electrochemical performances should shed light on the practical application of highly attractive tin‐based anodes for next generation rechargeable sodium batteries.  相似文献   

14.
Aqueous Zn‐ion batteries (ZIBs) have garnered the researchers' spotlight owing to its high safety, cost effectiveness, and high theoretical capacity of Zn anode. However, the availability of cathode materials for Zn ions storage is limited. With unique layered structure along the [010] direction, α‐MoO3 holds great promise as a cathode material for ZIBs, but its intrinsically poor conductivity severely restricts the capacity and rate capability. To circumvent this issue, an efficient surface engineering strategy is proposed to significantly improve the electric conductivity, Zn ion diffusion rate, and cycling stability of the MoO3 cathode for ZIBs, thus drastically promoting its electrochemical properties. With the synergetic effect of Al2O3 coating and phosphating process, the constructed Zn//P‐MoO3?x@Al2O3 battery delivers impressive capacity of 257.7 mAh g?1 at 1 A g?1 and superior rate capability (57% capacity retention at 20 A g?1), dramatically surpassing the pristine Zn//MoO3 battery (115.8 mAh g?1; 19.7%). More importantly, capitalized on polyvinyl alcohol gel electrolyte, an admirable capacity (19.2 mAh cm?3) as well as favorable energy density (14.4 mWh cm?3; 240 Wh kg?1) are both achieved by the fiber‐shaped quasi‐solid‐state ZIB. This work may be a great motivation for further research on molybdenum or other layered structure materials for high‐performance ZIBs.  相似文献   

15.
The further development of high‐power sodium‐ion batteries faces the severe challenge of achieving high‐rate cathode materials. Here, an integrated flexible electrode is constructed by smart combination of a conductive carbon cloth fiber skeleton and N‐doped carbon (NC) shell on Na3V2(PO4)3 (NVP) nanoparticles via a simple impregnation method. In addition to the great electronic conductivity and high flexibility of carbon cloth, the NC shell also promotes ion/electron transport in the electrode. The flexible NVP@NC electrode renders preeminent rate capacities (80.7 mAh g?1 at 50 C for cathode; 48 mAh g?1 at 30 C for anode) and superior cycle performance. A flexible symmetric NVP@NC//NVP@NC full cell is endowed with fairly excellent rate performance as well as good cycle stability. The results demonstrate a powerful polybasic strategy design for fabricating electrodes with optimal performance.  相似文献   

16.
1D branched TiO2 nanomaterials play a significant role in efficient photocatalysis and high‐performance lithium ion batteries. In contrast to the typical methods which generally have to employ epitaxial growth, the direct in situ growth of hierarchically branched TiO2 nanofibers by a combination of the electrospinning technique and the alkali‐hydrothermal process is presented in this work. Such the branched nanofibers exhibit improvement in terms of photocatalytic hydrogen evolution (0.41 mmol g−1 h−1), in comparison to the conventional TiO2 nanofibers (0.11 mmol g−1 h−1) and P25 (0.082 mmol g−1 h−1). Furthermore, these nanofibers also deliver higher lithium specific capacity at different current densities, and the specific capacity at the rate of 2 C is as high as 201. 0 mAh g−1, roughly two times higher than that of the pristine TiO2 nanofibers.  相似文献   

17.
Potassium‐ion batteries (PIBs) configurated by organic electrodes have been identified as a promising alternative to lithium‐ion batteries. Here, a porous organic Polyimide@Ketjenblack is demonstrated in PIBs as a cathode, which exhibits excellent performance with a large reversible capacity (143 mAh g?1 at 100 mA g?1), high rate capability (125 and 105 mAh g?1 at 1000 and 5000 mA g?1), and long cycling stability (76% capacity retention at 2000 mA g?1 over 1000 cycles). The domination of fast capacitive‐like reaction kinetics is verified, which benefits from the porous structure synthesized using in situ polymerization. Moreover, a renewable and low‐cost full cell is demonstrated with superior rate behavior (106 mAh g?1 at 3200 mA g?1). This work proposes a strategy to design polymer electrodes for high‐performance organic PIBs.  相似文献   

18.
The combination of high‐capacity and long‐term cycling stability is an important factor for practical application of anode materials for lithium‐ion batteries. Herein, NixMnyCozO nanowire (x + y + z = 1)/carbon nanotube (CNT) composite microspheres with a 3D interconnected conductive network structure (3DICN‐NCS) are prepared via a spray‐drying method. The 3D interconnected conductive network structure can facilitate the penetration of electrolyte into the microspheres and provide excellent connectivity for rapid Li+ ion/electron transfer in the microspheres, thus greatly reducing the concentration polarization in the electrode. Additionally, the empty spaces among the nanowires in the network accommodate microsphere volume expansion associated with Li+ intercalation during the cycling process, which improves the cycling stability of the electrode. The CNTs distribute uniformly in the microspheres, which act as conductive frameworks to greatly improve the electrical conductivity of the microspheres. As expected, the prepared 3DICN‐NCS demonstrates excellent electrochemical performance, showing a high capacity of 1277 mAh g?1 at 1 A g?1 after 2000 cycles and 790 mAh g?1 at 5 A g?1 after 1000 cycles. This work demonstrates a universal method to construct a 3D interconnected conductive network structure for anode materials  相似文献   

19.
With extremely high specific capacity, silicon has attracted enormous interest as a promising anode material for next‐generation lithium‐ion batteries. However, silicon suffers from a large volume variation during charge/discharge cycles, which leads to the pulverization of the silicon and subsequent separation from the conductive additives, eventually resulting in rapid capacity fading and poor cycle life. Here, it is shown that the utilization of a self‐healable supramolecular polymer, which is facilely synthesized by copolymerization of tert‐butyl acrylate and an ureido‐pyrimidinone monomer followed by hydrolysis, can greatly reduce the side effects caused by the volume variation of silicon particles. The obtained polymer is demonstrated to have an excellent self‐healing ability due to its quadruple‐hydrogen‐bonding dynamic interaction. An electrode using this self‐healing supramolecular polymer as binder exhibits an initial discharge capacity as high as 4194 mAh g−1 and a Coulombic efficiency of 86.4%, and maintains a high capacity of 2638 mAh g−1 after 110 cycles, revealing significant improvement of the electrochemical performance in comparison with that of Si anodes using conventional binders. The supramolecular binder can be further applicable for silicon/carbon anodes and therefore this supramolecular strategy may increase the choice of amendable binders to improve the cycle life and energy density of high‐capacity Li‐ion batteries.  相似文献   

20.
1T phase MoS2 possesses higher conductivity than the 2H phase, which is a key parameter of electrochemical performance for lithium ion batteries (LIBs). Herein, a 1T‐MoS2/C hybrid is successfully synthesized through facile hydrothermal method with a proper glucose additive. The synthesized hybrid material is composed of smaller and fewer‐layer 1T‐MoS2 nanosheets covered by thin carbon layers with an enlarged interlayer spacing of 0.94 nm. When it is used as an anode material for LIBs, the enlarged interlayer spacing facilitates rapid intercalating and deintercalating of lithium ions and accommodates volume change during cycling. The high intrinsic conductivity of 1T‐MoS2 also contributes to a faster transfer of lithium ions and electrons. Moreover, much smaller and fewer‐layer nanosheets can shorten the diffusion path of lithium ions and accelerate reaction kinetics, leading to an improved electrochemical performance. It delivers a high initial capacity of 920.6 mAh g?1 at 1 A g?1 and the capacity can maintain 870 mAh g?1 even after 300 cycles, showing a superior cycling stability. The electrode presents a high rate performance as well with a reversible capacity of 600 mAh g?1 at 10 A g?1. These results show that the 1T‐MoS2/C hybrid shows potential for use in high‐performance lithium‐ion batteries.  相似文献   

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