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1.
Sodium (Na) super ion conductor structured Na3V2(PO4)3 (NVP) is extensively explored as cathode material for sodium‐ion batteries (SIBs) due to its large interstitial channels for Na+ migration. The synthesis of 3D graphene‐like structure coated on NVP nanoflakes arrays via a one‐pot, solid‐state reaction in molten hydrocarbon is reported. The NVP nanoflakes are uniformly coated by the in situ generated 3D graphene‐like layers with the thickness of 3 nm. As a cathode material, graphene covered NVP nanoflakes exhibit excellent electrochemical performances, including close to theoretical reversible capacity (115.2 mA h g?1 at 1 C), superior rate capability (75.9 mA h g?1 at 200 C), and excellent cyclic stability (62.5% of capacity retention over 30000 cycles at 50 C). Furthermore, the 3D graphene‐like cages after removing NVP also serve as a good anode material and deliver a specific capacity of 242.5 mA h g?1 at 0.1 A g?1. The full SIB using these two cathode and anode materials delivers a high specific capacity (109.2 mA h g?1 at 0.1 A g?1) and good cycling stability (77.1% capacity retention over 200 cycles at 0.1 A g?1).  相似文献   

2.
Searching for a new material to build the next‐generation rechargeable lithium‐ion batteries (LIBs) with high electrochemical performance is urgently required. Owing to the low‐cost, non‐toxicity, and high‐safety, the family of manganese oxide including the Na‐Mn‐O system is regarded as one of the most promising electrode materials for LIBs. Herein, a new strategy is carried out to prepare a highly porous and electrochemically active Na0.55Mn2O4·1.5H2O (SMOH) compound. As an anode material, the Na‐Mn‐O nanocrystal material dispersed within a carbon matrix manifests a high reversible capacity of 1015.5 mA h g?1 at a current density of 0.1 A g?1. Remarkably, a considerable capability of 546.8 mA h g?1 remains even after 2000 discharge/charge cycles at the higher current density of 4 A g?1, indicating a splendid cyclability. The exceptional electrochemical properties allow SMOH to be a promising anode material toward LIBs.  相似文献   

3.
A simple ball‐milling method is used to synthesize a tin oxide‐silicon carbide/few‐layer graphene core‐shell structure in which nanometer‐sized SnO2 particles are uniformly dispersed on a supporting SiC core and encapsulated with few‐layer graphene coatings by in situ mechanical peeling. The SnO2‐SiC/G nanocomposite material delivers a high reversible capacity of 810 mA h g?1 and 83% capacity retention over 150 charge/discharge cycles between 1.5 and 0.01 V at a rate of 0.1 A g?1. A high reversible capacity of 425 mA h g?1 also can be obtained at a rate of 2 A g?1. When discharged (Li extraction) to a higher potential at 3.0 V (vs. Li/Li+), the SnO2‐SiC/G nanocomposite material delivers a reversible capacity of 1451 mA h g?1 (based on the SnO2 mass), which corresponds to 97% of the expected theoretical capacity (1494 mA h g?1, 8.4 equivalent of lithium per SnO2), and exhibits good cyclability. This result suggests that the core‐shell nanostructure can achieve a completely reversible transformation from Li4.4Sn to SnO2 during discharging (i.e., Li extraction by dealloying and a reversible conversion reaction, generating 8.4 electrons). This suggests that simple mechanical milling can be a powerful approach to improve the stability of high‐performance electrode materials involving structural conversion and transformation.  相似文献   

4.
Identifying suitable electrode materials for sodium‐ion and potassium‐ion storage holds the key to the development of earth‐abundant energy‐storage technologies. This study reports an anode material based on self‐assembled hierarchical spheroid‐like KTi2(PO4)3@C nanocomposites synthesized via an electrospray method. Such an architecture synergistically combines the advantages of the conductive carbon network and allows sufficient space for the infiltration of the electrolyte from the porous structure, leading to an impressive electrochemical performance, as reflected by the high reversible capacity (283.7 mA h g?1 for Na‐ion batteries; 292.7 mA h g?1 for K‐ion batteries) and superior rate capability (136.1 mA h g?1 at 10 A g?1 for Na‐ion batteries; 133.1 mA h g?1 at 1 A g?1 for K‐ion batteries) of the resulting material. Moreover, the different ion diffusion behaviors in the two systems are revealed to account for the difference in rate performance. These findings suggest that KTi2(PO4)3@C is a promising candidate as an anode material for sodium‐ion and potassium‐ion batteries. In particular, the present synthetic approach could be extended to other functional electrode materials for energy‐storage materials.  相似文献   

5.
Inspired by the great success of graphite in lithium‐ion batteries, anode materials that undergo an intercalation mechanism are considered to provide stable and reversible electrochemical sodium‐ion storage for sodium‐ion battery (SIB) applications. Though MoS2 is a promising 2D material for SIBs, it suffers from deformation of its layered structure during repeated intercalation of Na+, resulting in undesirable electrochemical behaviors. In this study, vertically oriented MoS2 on nitrogenous reduced graphene oxide sheets (VO‐MoS2/N‐RGO) is presented with designed spatial geometries, including sheet density and height, which can deliver a remarkably high reversible capacity of 255 mA h g?1 at a current density of 0.2 A g?1 and 245 mA h g?1 at a current density of 1 A g?1, with a total fluctuation of 5.35% over 1300 cycles. These results are superior to those obtained with well‐developed hard carbon structures. Furthermore, a SIB full cell composed of the optimized VO‐MoS2/N‐RGO anode and a Na2V3(PO4)3 cathode reaches a specific capacity of 262 mA h g?1 (based on the anode mass) during 50 cycles, with an operated voltage range of 2.4 V, demonstrating the potentially rewarding SIB performance, which is useful for further battery development.  相似文献   

6.
Sodium‐ion batteries (SIBs) have a promising application prospect for energy storage systems due to the abundant resource. Amorphous carbon with high electronic conductivity and high surface area is likely to be the most promising anode material for SIBs. However, the rate capability of amorphous carbon in SIBs is still a big challenge because of the sluggish kinetics of Na+ ions. Herein, a three‐dimensional amorphous carbon (3DAC) with controlled porous and disordered structures is synthesized via a facile NaCl template‐assisted method. Combination of open porous structures of 3DAC, the increased disordered structures can not only facilitate the diffusion of Na+ ions but also enhance the reversible capacity of Na storage. When applied as anode materials for SIBs, 3DAC exhibits excellent rate capability (66 mA h g?1 at 9.6 A g?1) and high reversible capacity (280 mA h g?1 at a low current density of 0.03 A g?1). Moreover, the controlled porous structures by the NaCl template method provide an appropriate specific surface area, which contributes to a relatively high initial Coulombic efficiency of 75%. Additionally, the high‐rate 3DAC material is prepared via a green approach originating from low‐cost pitch and NaCl template, demonstrating an appealing development of carbon anode materials for SIBs.  相似文献   

7.
SnS2 nanoplatelet electrodes can offer an exceptionally high pseudocapacitance in an organic Na+ ion electrolyte system, but their underlying mechanisms are still largely unexplored, hindering the practical applications of pseudocapacitive SnS2 anodes in Na‐ion batteries (SIBs) and Na hybrid capacitors (SHCs). Herein, SnS2 nanoplatelets are grown directly on SnO2/C composites to synthesize SnS2/graphene‐carbon nanotube aerogel (SnS2/GCA) by pressurized sulfidation where the original morphology of carbon framework is preserved. The composite electrode possessing a large surface area delivers a remarkable specific capacity of 600.3 mA h g?1 at 0.2 A g?1 and 304.8 mA h g?1 at an ultrahigh current density of 10 A g?1 in SIBs. SHCs comprising a SnS2/GCA composite anode and an activated carbon cathode present exceptional energy densities of 108.3 and 26.9 W h kg?1 at power densities of 130 and 6053 W kg?1, respectively. The in situ transmission electron microscopy and the density functional theory calculations reveal that the excellent pseudocapacitance originates from the combination of Na adsorption on the surface/Sn edge of SnS2 nanoplatelets and ultrafast Na+ ion intercalation into the SnS2 layers.  相似文献   

8.
Prussian blue analogs (PBAs) are especially investigated as superior cathodes for sodium‐ion batteries (SIBs) due to high theoretical capacity (≈170 mA h g?1) with 2‐Na storage and low cost. However, PBAs suffer poor cyclability due to irreversible phase transition in deep charge/discharge states. PBAs also suffer low crystallinity, with considerable [Fe(CN)6] vacancies, and coordinated water in crystal frameworks. Presently, a new chelating agent/surfactant coassisted crystallization method is developed to prepare high‐quality (HQ) ternary‐metal NixCo1?x[Fe(CN)6] PBAs. By introducing inactive metal Ni to suppress capacity fading caused by excessive lattice distortion, these PBAs have tunable limits on depth of charge/discharge. HQ‐NixCo1?x[Fe(CN)6] (x = 0.3) demonstrates the best reversible Na‐storage behavior with a specific capacity of ≈145 mA h g?1 and a remarkably improved cycle performance, with ≈90% capacity retention over 600 cycles at 5 C. Furthermore, a dual‐insertion full cell on the cathode and NaTi2(PO4)3 anode delivers reversible capacity of ≈110 mA h g?1 at a current rate of 1.0 C without capacity fading over 300 cycles, showing promise as a high‐performance SIB for large‐scale energy‐storage systems. The ultrastable cyclability achieved in the lab and explained herein is far beyond that of any previously reported PBA‐based full cells.  相似文献   

9.
Sodium‐ion batteries are considered alternatives to lithium‐ion batteries for energy storage devices due to their competitive cost and source abundance. However, the development of electrode materials with long‐term stability and high capacity remains a great challenge. Here, this paper describes for the first time the synthesis of a new class of core–shell MAX@K2Ti8O17 by alkaline hydrothermal reaction and hydrogenation of MAX, which grants high sodium ion‐intercalation pseudocapacitance. This composite electrode displays extraordinary reversible capacities of 190 mA h g?1 at 200 mA g?1 (0.9 C, theoretical value of ≈219 mA h g?1) and 150 mA h g?1 at 1000 mA g?1 (4.6 C). More importantly, a reversible capacity of 75 mA h g?1 at 10 000 mA g?1 (46 C) is retained without any apparent capacity decay even after more than 10 000 cycles. Experimental tests and first‐principle calculations confirm that the increase in Ti3+ on the surface layers of MAX@K2Ti8O17 by hydrogenation increases its conductivity in addition to enhancing the sodium‐ion intercalation pseudocapacitive process. Furthermore, the distorted dodecahedrons between Ti and O layers not only provide abundant sites for sodium‐ion accommodation but also act as wide tunnels for sodium‐ion transport.  相似文献   

10.
Rechargeable sodium–iodine batteries represent a promising scalable electrochemical energy storage alternative as sodium and iodine are both low cost and widely abundant elements. Here, the authors demonstrate a rechargeable sodium–iodine battery that employs free‐standing iodine quantum dots (IQDs) decorated reduced graphene oxide (IQDs@RGO) as the cathode. Consistent with the density functional theory the authors find the Na+ ions to intercalate into the I unit cell forming stable NaI, and the battery exhibits high capacity, outstanding cycle stability (with a reversible specific capacity of 141 mA h g?1 after 500 cycles at current density of 100 mA g?1), and high rate performance (170, 146, 127, 112, and 95 mA h g?1 at current densities of 100, 200, 400, 600, and 1000 mA g?1, respectively). The reversible reactions, I2/I3 ? and I3 ?/I? redox couples on insertion of Na+ ions, are confirmed via in situ Raman spectroscopy. Notably, even after 500 cycles the morphology and structure of the IQDs exhibit no noticeable change implying their use as a stable cathode material for sodium–iodine batteries. Moreover, the IQDs based flexible full‐cells also exhibit high capacity and long cycle life (the capacity with 123 mA h g?1 at current density of 100 mA g?1 after 100 cycles).  相似文献   

11.
Na3V2(PO4)3 (NVP) is regarded as a promising cathode for advanced sodium‐ion batteries (SIBs) due to its high theoretical capacity and stable sodium (Na) super ion conductor (NASICON) structure. However, strongly impeded by its low electronic conductivity, the general NVP delivers undesirable rate capacity and fails to meet the demands for quick charge. Herein, a novel and facile synthesis of layer‐by‐layer NVP@reduced graphene oxide (rGO) nanocomposite is presented through modifying the surface charge of NVP gel precursor. The well‐designed layered NVP@rGO with confined NVP nanocrystal in between rGO layers offers high electronic and ionic conductivity as well as stable structure. The NVP@rGO nanocomposite with merely ≈3.0 wt% rGO and 0.5 wt% amorphous carbon, yet exhibits extraordinary electrochemical performance: a high capacity (118 mA h g?1 at 0.5 C attaining the theoretical value), a superior rate capability (73 mA h g?1 at 100 C and even up to 41 mA h g?1 at 200 C), ultralong cyclability (70.0% capacity retention after 15 000 cycles at 50 C), and stable cycling performance and excellent rate capability at both low and high operating temperatures. The proposed method and designed layer‐by‐layer active nanocrystal@rGO strategy provide a new avenue to create nanostructures for advanced energy storage applications.  相似文献   

12.
Sodium‐based dual ion full batteries (NDIBs) are reported with soft carbon as anode and graphite as cathode for the first time. The NDIBs operate at high discharge voltage plateau of 3.58 V, with superior discharge capacity of 103 mA h g?1, excellent rate performance, and long‐term cycling stability over 800 cycles with capacity retention of 81.8%. The mechanism of Na+ and PF6? insertion/desertion during the charging/discharging processes is proposed and discussed in detail, with the support of various spectroscopies.  相似文献   

13.
Herein, P′2‐type Na0.67[Ni0.1Fe0.1Mn0.8]O2 is introduced as a promising new cathode material for sodium‐ion batteries (SIBs) that exhibits remarkable structural stability during repetitive Na+ de/intercalation. The O? Ni? O? Mn? O? Fe? O bond in the octahedra of transition‐metal layers is used to suppress the elongation of the Mn? O bond and to improve the electrochemical activity, leading to the highly reversible Na storage mechanism. A high discharge capacity of ≈220 mAh g?1 (≈605 Wh kg?1) is delivered at 0.05 C (13 mAg?1) with a high reversible capacity of ≈140 mAh g?1 at 3 C and excellent capacity retention of 80% over 200 cycles. This performance is associated with the reversible P′2–OP4 phase transition and small volume change upon charge and discharge (≈3%). The nature of the sodium storage mechanism in a full cell paired with a hard carbon anode reveals an unexpectedly high energy density of ≈542 Wh kg?1 at 0.2 C and good capacity retention of ≈81% for 500 cycles at 1 C (260 mAg?1).  相似文献   

14.
Energy‐storage technology is moving beyond lithium batteries to sodium as a result of its high abundance and low cost. However, this sensible transition requires the discovery of high‐rate and long‐lifespan anode materials, which remains a significant challenge. Here, the facile synthesis of an amorphous Sn2P2O7/reduced graphene oxide nanocomposite and its sodium storage performance between 0.01 and 3.0 V are reported for the first time. This hybrid electrode delivers a high specific capacity of 480 mA h g?1 at a current density of 50 mA g?1 and superior rate performance of 250 and 165 mA h g?1 at 2 and 10 A g?1, respectively. Strikingly, this anode can sustain 15 000 cycles while retaining over 70% of the initial capacity. Quantitative kinetic analysis reveals that the sodium storage is governed by pseudocapacitance, particularly at high current rates. A full cell with sodium super ionic conductor (NASICON)‐structured Na3V2(PO4)2F3 and Na3V2(PO4)3 as cathodes exhibits a high energy density of over 140 W h kg?1 and a power density of nearly 9000 W kg?1 as well as stability over 1000 cycles. This exceptional performance suggests that the present system is a promising power source for promoting the substantial use of low‐cost energy storage systems.  相似文献   

15.
Hard carbon (HC) is the state‐of‐the‐art anode material for sodium‐ion batteries (SIBs). However, its performance has been plagued by the limited initial Coulombic efficiency (ICE) and mediocre rate performance. Here, experimental and theoretical studies are combined to demonstrate the application of lithium‐pretreated HC (LPHC) as high‐performance anode materials for SIBs by manipulating the solid electrolyte interphase in tetraglyme (TEGDME)‐based electrolyte. The LPHC in TEGDME can 1) deliver > 92% ICE and ≈220 mAh g?1 specific capacity, twice of the capacity (≈100 mAh g?1) in carbonate electrolyte; 2) achieve > 85% capacity retention over 1000 cycles at 1000 mA g?1 current density (4 C rate, 1 C = 250 mA g?1) with a specific capacity of ≈150 mAh g?1, ≈15 times of the capacity (10 mAh g?1) in carbonate. The full cell of Na3V2(PO4)3‐LPHC in TEGDME demonstrated close to theoretical specific capacity of ≈98 mAh g?1 based on Na3V2(PO4)3 cathode, ≈2.5 times of the value (≈40 mAh g?1) with nontreated HC. This work provides new perception on the anode development for SIBs.  相似文献   

16.
Covalent organic framework (COF) can grow into self‐exfoliated nanosheets. Their graphene/graphite resembling microtexture and nanostructure suits electrochemical applications. Here, covalent organic nanosheets (CON) with nanopores lined with triazole and phloroglucinol units, neither of which binds lithium strongly, and its potential as an anode in Li‐ion battery are presented. Their fibrous texture enables facile amalgamation as a coin‐cell anode, which exhibits exceptionally high specific capacity of ≈720 mA h g?1 (@100 mA g?1). Its capacity is retained even after 1000 cycles. Increasing the current density from 100 mA g?1 to 1 A g?1 causes the specific capacity to drop only by 20%, which is the lowest among all high‐performing anodic COFs. The majority of the lithium insertion follows an ultrafast diffusion‐controlled intercalation (diffusion coefficient, DLi+ = 5.48 × 10?11 cm2 s?1). The absence of strong Li‐framework bonds in the density functional theory (DFT) optimized structure supports this reversible intercalation. The discrete monomer of the CON shows a specific capacity of only 140 mA h g?1 @50 mA g?1 and no sign of lithium intercalation reveals the crucial role played by the polymeric structure of the CON in this intercalation‐assisted conductivity. The potentials mapped using DFT suggest a substantial electronic driving‐force for the lithium intercalation. The findings underscore the potential of the designer CON as anode material for Li‐ion batteries.  相似文献   

17.
Layered sodium titanium oxide, Na2Ti3O7, is synthesized by a solid‐state reaction method as a potential anode for sodium‐ion batteries. Through optimization of the electrolyte and binder, the microsized Na2Ti3O7 electrode delivers a reversible capacity of 188 mA h g?1 in 1 M NaFSI/PC electrolyte at a current rate of 0.1C in a voltage range of 0.0–3.0 V, with sodium alginate as binder. The average Na storage voltage plateau is found at ca. 0.3 V vs. Na+/Na, in good agreement with a first‐principles prediction of 0.35 V. The Na storage properties in Na2Ti3O7 are investigated from thermodynamic and kinetic aspects. By reducing particle size, the nanosized Na2Ti3O7 exhibits much higher capacity, but still with unsatisfied cyclic properties. The solid‐state interphase layer on Na2Ti3O7 electrode is analyzed. A zero‐current overpotential related to thermodynamic factors is observed for both nano‐ and microsized Na2Ti3O7. The electronic structure, Na+ ion transport and conductivity are investigated by the combination of first‐principles calculation and electrochemical characterizations. On the basis of the vacancy‐hopping mechanism, a quasi‐3D energy favorable trajectory is proposed for Na2Ti3O7. The Na+ ions diffuse between the TiO6 octahedron layers with pretty low activation energy of 0.186 eV.  相似文献   

18.
An all‐organic battery consisting of two redox‐polymers, namely poly(2‐vinylthianthrene) and poly(2‐methacrylamide‐TCAQ) is assembled. This all‐organic battery shows excellent performance characteristics, namely flat discharge plateaus, an output voltage exceeding 1.3 V, and theoretical capacities of both electrodes higher than 100 mA h g?1. Both organic electrode materials are synthesized in two respective three synthetic steps using the free‐radical polymerization technique. Li‐organic batteries manufactured from these polymers prove their suitability as organic electrode materials. The cathode material poly(2‐vinylthianthrene) (3) displays a discharging plateau at 3.95 V versus Li+/Li and a discharge capacity of 105 mA h g?1, corresponding to a specific energy of about 415 mW h g?1. The anode material poly(2‐methacrylamide‐TCAQ) (7) exhibits an initial discharge capacity of 130 mA h g?1, corresponding to 94% material activity. The combination of both materials results in an all‐organic battery with a discharge voltage of 1.35 V and an initial discharge capacity of 105 mA h g?1 (95% material activity).  相似文献   

19.
Phosphorus and tin phosphide based materials that are extensively researched as the anode for Na‐ion batteries mostly involve complexly synthesized and sophisticated nanocomposites limiting their commercial viability. This work reports a Sn4P3‐P (Sn:P = 1:3) @graphene nanocomposite synthesized with a novel and facile mechanochemical method, which exhibits unrivalled high‐rate capacity retentions of >550 and 371 mA h g?1 at 1 and 2 A g?1, respectively, over 1000 cycles and achieves excellent rate capability (>815, ≈585 and ≈315 mA h g?1 at 0.1, 2, and 10 A g?1, respectively).  相似文献   

20.
Different from previously reported mechanical alloying route to synthesize Sn x P3, novel Sn4P3/reduced graphene oxide (RGO) hybrids are synthesized for the first time through an in situ low‐temperature solution‐based phosphorization reaction route from Sn/RGO. Sn4P3 nanoparticles combining with advantages of high conductivity of Sn and high capacity of P are homogenously loaded on the RGO nanosheets, interconnecting to form 3D mesoporous architecture nanostructures. The Sn4P3/RGO hybrid architecture materials exhibit significantly improved electrochemical performance of high reversible capacity, high‐rate capability, and excellent cycling performance as sodium ion batteries (SIBs) anode materials, showing an excellent reversible capacity of 656 mA h g?1 at a current density of 100 mA g?1 over 100 cycles, demonstrating a greatly enhanced rate capability of a reversible capacity of 391 mA h g?1 even at a high current density of 2.0 A g?1. Moreover, Sn4P3/RGO SIBs anodes exhibit a superior long cycling life, delivering a high capacity of 362 mA h g?1 after 1500 cycles at a high current density of 1.0 A g?1. The outstanding cycling performance and rate capability of these porous hierarchical Sn4P3/RGO hybrid anodes can be attributed to the advantage of porous structure, and the synergistic effect between Sn4P3 nanoparticles and RGO nanosheets.  相似文献   

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