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1.
    
Chalcogenide cathodes with multi-electron transfer characteristics are indispensable to aluminum-ion batteries (AIBs). Nevertheless, their grievous capacity degradation and sluggish reaction kinetics remain fundamental challenges for the practical application. Herein, a Cu2S/Ni3S2 multiphase structure within the metal-organic frame (MOF) derived carbon decoration layer (CNS@MC) is constructed to elevate the intrinsic electronic properties of chalcogenide cathode and realize high-performance AIBs. The existence of outer carbon layer and strong orbital interaction at inner heterointerfaces eliminates the bandgap and arises more electrons at Fermi level, efficiently reducing the energy barrier for electron transfer and achieving high reactivity within cathodes. The CNS@MC also presents a strong electronic interaction with active solvent groups, which is beneficial to capture Al3+ and facilitate the three-electron charge-storage reactions. Experimental results demonstrate that the tailored CNS@MC cathode possesses superior redox kinetics due to the sufficient surface area and rapid Al-ion diffusion during cycling. Meanwhile, the robust CNS@MC delivers ultra-high electrochemical stability (131.1 mAh g−1 over 3500 cycles) with high coulombic efficiency and outstanding rate performance. This work offers new opportunities for optimizing the intrinsic properties of the chalcogenide electrodes based on MOF derivatives and heterostructure, providing novel thoughts for designing high-performance AIBs.  相似文献   

2.
    
A kind of graphene‐based nanoporous material is prepared through assembling graphene sheets mediated through polyoxometalate nanoparticles. Owing to the strong interaction between graphene and polyoxometalate, 2D graphene sheets with honeycomb‐latticed carbon atoms could assemble into a porous structure, in which 3D polyoxometalate nanoparticles serve as the crosslinkers. Nitrogen and hydrogen sorption analysis reveal that the as‐prepared graphene‐based hybrid material possesses a specific surface area of 680 m2 g?1 and a hydrogen uptake volume of 0.8?1.3 wt%. Infrared spectrometry is used to probe the electron density changes of polyoxometalate particle in the redox‐cycle and to verify the interaction between graphene and polyoxometalate. The as‐prepared graphene‐based materials are further characterized by Raman spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy.  相似文献   

3.
    
Aluminum is an attractive anode material in aqueous multivalent-metal batteries for large-scale energy storage because of its high Earth abundance, low cost, high theoretic capacity, and safety. However, state-of-the-art aqueous aluminum-ion batteries based on aluminum anode persistently suffer from poor rechargeability and low coulombic efficiency due to irreversibility of aluminum stripping/plating and dendrite growth. Here eutectic aluminum-cerium alloys in situ grafted with uniform ultrathin MXene (MXene/E-Al97Ce3) as flexible, reversible, and dendrite-free anode materials for rechargeable aqueous aluminum-ion batteries is reported. As a result of the MXene serving as stable solid electrolyte interphase to inhibit side reactions and the lamella-nanostructured E-Al97Ce3 enabling directional Al stripping and deposition by making use of symbiotic α-Al metal and intermetallic Al11Ce3 lamellas, the MXene/E-Al97Ce3 hybrid electrodes exhibit reversible and dendrite-free Al stripping/plating with low voltage polarization of ± 54 mV for ≥1000 h in a low-oxygen-concentration aqueous aluminum trifluoromethanesulfonate (Al(OTF)3) electrolyte. These superior electrochemical properties endow soft-package aluminum-ion batteries assembled with MXene/E-Al97Ce3 anode and AlxMnO2 cathode to have high initial discharge capacity of ≈360 mAh g−1 at 1 A g−1, and retain ≈85% after 500 cycles, along with the coulombic efficiency of as high as 99.5%.  相似文献   

4.
    
Aqueous zinc-based batteries have garnered considerable interest as promising energy storage devices due to the low cost, remarkable energy density, high safety, and eco-friendliness. However, the mutual challenges of cathode dissolution, electrolyte parasitic reactions, disordered zinc dendrite growth, and easily punctured separator have significantly impeded the widespread commercialization of aqueous zinc-based batteries. Realizing high-performance zinc-based batteries becomes imperative yet remains extremely challenging. To address these concerns, great efforts have recently been made to design high-performance zinc-based batteries. Here the state-of-the-art in organic materials is critically reviewed for aqueous zinc-based batteries, covering main components of a battery. This review provides a comprehensive overview on the design strategies of organic materials for zinc-based batteries, encompassing cathode, anode, electrolyte, and separator. Furthermore, the challenges and prospective research directions are also discussed to provide a guideline for further development of highly stable zinc-based batteries.  相似文献   

5.
    
High capacity electrodes based on a Si composite anode and a layered composite oxide cathode, Ni‐rich Li[Ni0.75Co0.1Mn0.15]O2, are evaluated and combined to fabricate a high energy lithium ion battery. The Si composite anode, Si/C‐IWGS (internally wired with graphene sheets), is prepared by a scalable sol–gel process. The Si/C‐IWGS anode delivers a high capacity of >800 mAh g?1 with an excellent cycling stability of up to 200 cycles, mainly due to the small amount of graphene (～6 wt%). The cathode (Li[Ni0.75Co0.1Mn0.15]O2) is structurally optimized (Ni‐rich core and a Ni‐depleted shell with a continuous concentration gradient between the core and shell, i.e., a full concentration gradient, FCG, cathode) so as to deliver a high capacity (>200 mAh g?1) with excellent stability at high voltage (～4.3 V). A novel lithium ion battery system based on the Si/C‐IWGS anode and FCG cathode successfully demonstrates a high energy density (240 Wh kg?1 at least) as well as an unprecedented excellent cycling stability of up to 750 cycles between 2.7 and 4.2 V at 1C. As a result, the novel battery system is an attractive candidate for energy storage applications demanding a high energy density and long cycle life.  相似文献   

6.
    
The development of high‐energy and high‐power density sodium‐ion batteries is a great challenge for modern electrochemistry. The main hurdle to wide acceptance of sodium‐ion batteries lies in identifying and developing suitable new electrode materials. This study presents a composition‐graded cathode with average composition Na[Ni0.61Co0.12Mn0.27]O2, which exhibits excellent performance and stability. In addition to the concentration gradients of the transition metal ions, the cathode is composed of spoke‐like nanorods assembled into a spherical superstructure. Individual nanorod particles also possess strong crystallographic texture with respect to the center of the spherical particle. Such morphology allows the spoke‐like nanorods to assemble into a compact structure that minimizes its porosity and maximizes its mechanical strength while facilitating Na+‐ion transport into the particle interior. Microcompression tests have explicitly verified the mechanical robustness of the composition‐graded cathode and single particle electrochemical measurements have demonstrated the electrochemical stability during Na+‐ion insertion and extraction at high rates. These structural and morphological features contribute to the delivery of high discharge capacities of 160 mAh (g oxide)?1 at 15 mA g?1 (0.1 C rate) and 130 mAh g?1 at 1500 mA g?1 (10 C rate). The work is a pronounced step forward in the development of new Na ion insertion cathodes with a concentration gradient.  相似文献   

7.
    
Aqueous rechargeable zinc batteries (ARZBs) are recently prevailing devices that utilize the abundant Zn resources and the merits of aqueous electrolytes to become a competitive alternative for large-scale energy storage. Benefiting from the unique inductive effect and flexible structure, the past five years have experienced a diversiform of phosphate-based polyanion materials that are used as cathodes in ARZBs. In this review, the most recent advances in the Zn2+ storage mechanisms and electrolyte optimization of the phosphate-based cathodes of ARZBs, which mainly focus on vanadium/iron-based phosphates and their derivatives are presented. Furthermore, in addition to significant progress on polyanion phosphate-based cathode materials, the design strategies both for electrode materials and compatible electrolytes are also elaborated to improve the energy density and extend the cycling life of aqueous Zn/polyanion batteries.  相似文献   

8.
    
Lithium sulfide (Li2S) has attracted increasing attention as a promising cathode because of its compatibility with more practical lithium‐free anode materials and its high specific capacity. However, it is still a challenge to develop Li2S cathodes with low electrochemical overpotential, high capacity and reversibility, and good rate performance. This work designs and fabricates a practical Li2S cathode composed of Li2S/few‐walled carbon nanotubes@reduced graphene oxide nanobundle forest (Li2S/FWNTs@rGO NBF). Hierarchical nanostructures are obtained by annealing the Li2SO4/FWNTs@GO NBF, which is prepared by a facile and scalable solution‐based self‐assembly method. Systematic characterizations reveal that in this unique NBF nanostructure, FWNTs act as axial shafts to direct the structure, Li2S serves as the internal active material, and GO sheets provide an external coating to minimize the direct contact of Li2S with the electrolyte. When used as a cathode, the Li2S/FWNTs@rGO NBF achieve a high capacity of 868 mAh g?1Li2S at 0.2C after 300 cycles and an outstanding rate performance of 433 mAh g?1Li2S even at 10C, suggesting that this Li2S cathode is a promising candidate for ultrafast charge/discharge applications. The design and synthetic strategies outlined here can be readily applied to the processing of other novel functional materials to obtain a much wider range of applications.  相似文献   

9.
    
TiO2 films of varying thicknesses (up to ≈1.0 µm) with vertically oriented, accessible 7–9 nm nanopores are synthesized using an evaporation‐induced self‐assembly layer‐by‐layer technique. The hypothesis behind the approach is that epitaxial alignment of hydrophobic blocks of surfactant templates induces a consistent, accessible mesophase orientation across a multilayer film, ultimately leading to continuous, vertically aligned pore channels. Characterization using grazing incidence X‐ray scattering, scanning electron microscopy, and impedance spectroscopy indicates that the pores are oriented vertically even in relatively thick films (up to 1 µm). These films contain a combination of amorphous and nanocrystalline anatase titania of value for electrochemical energy storage. When applied as negative electrodes in lithium‐ion batteries, a capacity of 254 mAh g?1 is obtained after 200 cycles for a single‐layer TiO2 film prepared on modified substrate, higher than on unmodified substrate or nonporous TiO2 film, due to the high accessibility of the vertically oriented channels in the films. Thicker films on modified substrate have increased absolute capacity because of higher mass loading but a reduced specific capacity because of transport limitations. These results suggest that the multilayer epitaxial approach is a viable way to prepare high capacity TiO2 films with vertically oriented continuous nanopores.  相似文献   

10.
    
A hierarchical, nanoporous TiO2 structure is successfully prepared by a simple in situ hydrolysis method. Used as an anode material, it achieves a sustained high lithium storage performance especially at high charge/discharge rates due to its substantially high surface area. The material shows two different major storage modes: a) bulk insertion, and b) pseudo‐capacitive interfacial storage, which is responsible for 64% of the total capacity. In order to kinetically emphasize the interfacial storage even further, we cycle the material directly at high rates, giving 302 mA h g?1 and 200 mA h g?1 of fully reversible discharge capacity at charge/discharge rates of 1 C and 5 C with very high cycle stability. We propose an overall view on the different Li insertion mechanisms of the high‐surface‐area nanoporous TiO2 and emphasize the importance of interfacial storage for electrode applications in Li‐ion batteries.  相似文献   

11.
    
Anionic redox activity can trigger structural instability in Li-rich Mn-based cathodes. Lattice oxygen activity can be tuned through liquid acid-induced spinel phases and oxygen vacancies. However, the liquid-acid-modified surface is still attacked by the electrolyte. Besides, the underlying mechanism of spinel phase suppression of lattice oxygen activity is controversial. Here, a solid acid strategy for modification is proposed and the underlying mechanism is investigated in detail. Unique solid acid can in situ generate an interface protection layer and remarkably stabilize the structure. Theoretical calculations and experimental characterizations reveal that the spinel phase suppresses the irreversible loss of lattice oxygen by decreasing the O 2p non-bonding energy level and enriching electrons at the layered/spinel phase interface. The inert layer on the surface prevents highly active On− from being attacked by electrolytes. The obtained material exhibits significantly reduced irreversible lattice oxygen release and improved electrochemical performance. After 300 cycles, a slow capacity fading of 0.177 mAh g−1 per cycle and suppressed voltage fading are achieved. This study reveals the regulation method and mechanism for the anion activity of oxide cathodes in next-generation Li-ion batteries.  相似文献   

12.
    
High-nickel layered oxide cathodes, such as LiNi1-x-yMnxCoyO2 (NMC) and LiNi1-x-yCoxAlyO2 (NCA), are at the forefront for implementation in high-energy-density lithium-ion batteries. The presence of cobalt in both cathode chemistries, however, largely deters their application due to fiscal and humanitarian issues affiliated with cobalt sourcing. Increasing the Ni content drives down the Co content, but introduces additional structural and electrochemical problems attributed to high-Ni cathodes. Herein a dually modified cobalt-free ultrahigh-nickel cathode 0.02B-LiNi0.99Mg0.01O2 (NBM) is presented with 1 mol% Mg and 2 mol% B that exhibits a high initial 1C discharge capacity of 210 mA h g−1 with a 20% capacity retention improvement over 500 cycles when benchmarked against LiNiO2 (LNO) in pouch full cell configurations with graphite anode. Postmortem analyses reveal the enhanced performance stems from reduced active lithium inventory loss and localized surface reactivity in the NBM cathode. The stabilized cathode-electrolyte interphase subsequently reduces transition-metal dissolution and ensuing chemical crossover to the graphite anode, which prevents further catalyzed parasitic reactions that harmfully passivate the anode surface. Altogether, this study aims to highlight the importance of electrode characterization and analysis from an interphasial viewpoint and to push the ongoing research to stabilize cobalt-free ultrahigh-Ni cathodes for industrial feasibility.  相似文献   

13.
    
Cathodes in lithium-ion batteries with anionic redox can deliver extraordinarily high specific capacities but also present many issues such as oxygen release, voltage hysteresis, and sluggish kinetics. Identifying problems and developing solutions for these materials are vital for creating high-energy lithium-ion batteries. Herein, the electrochemical and structural monitoring is conducted on lithium-rich cathodes to directly probe the formation processes of larger voltage hysteresis. These results indicate that the charge-compensation properties, structural evolution, and transition metal (TM) ions migration vary from oxidation to reduction process. This leads to huge differences in charge and discharge voltage profile. Meanwhile, the anionic redox processes display a slow kinetics process with large hysteresis (≈0.5 V), compared to fast cationic redox processes without any hysteresis. More importantly, a simple yet effective strategy has been proposed where fine-modulating local oxygen environment by the lithium/oxygen (Li/O) ratio tunes the anionic redox chemistry. This effectively improves its electrochemical properties, including the operating voltage and kinetics. This is also verified by theoretical calculations that adjusting anionic redox chemistry by the Li/O ratio shifts the TM 3d—O 2p bands and the non-bonding O 2p band to a lower energy level, resulting in a higher redox reaction potential.  相似文献   

14.
    
Branded with low cost and a high degree of safety, with an ambitious aim of substituting lithium-ion batteries in many fields, sodium-ion batteries have received fervid attention in recent years after being dormant for decades. Layered materials are a major focus of study owing to the extensive experience already gained in lithium-ion batteries, and the pursuit of a Mn-rich composition is critical to reduce the cost while retaining the performance. This review provides a timely update of the recent progress of Mn-rich layered materials for sodium-ion batteries based on the understandings of the phase forming principles, structure transformation upon cycling and charge compensation mechanisms and discusses potential ambiguities in the pursuit of high-performance materials.  相似文献   

15.
Vanadium multiredox-based NASICON-NazV2−yMy(PO4)3 (3 ≤ z ≤ 4; M = Al3+, Cr3+, and Mn2+) cathodes are particularly attractive for Na-ion battery applications due to their high Na insertion voltage (>3.5 V vs Na+/Na0), reversible storage capacity (≈150 mA h g−1), and rate performance. However, their practical application is hindered by rapid capacity fade due to bulk structural rearrangements at high potentials involving complex redox and local structural changes. To decouple these factors, a series of Mg2+-substituted Na3+yV2−yMgy(PO4)3 (0 ≤ y ≤ 1) cathodes is studied for which the only redox-active species is vanadium. While X-ray diffraction (XRD) confirms the formation of solid solutions between the y = 0 and 1 end members, X-ray absorption spectroscopy and solid-state nuclear magnetic resonance reveal a complex evolution of the local structure upon progressive Mg2+ substitution for V3+. Concurrently, the intercalation voltage rises from 3.35 to 3.45 V, due to increasingly more ionic V O bonds, and the sodium (de)intercalation mechanism transitions from a two-phase for y ≤ 0.5 to a solid solution process for y ≥ 0.5, as confirmed by in operando XRD, while Na-ion diffusion kinetics follow a nonlinear trend across the compositional series.  相似文献   

16.
    
Lithium-sulfur batteries (LSBs) with high theoretical specific capacities have been regarded as the development direction of next generation energy storage. However, the shuttle effect of lithium polysulfides (LiPSs) and the retardation of conversion kinetics have hindered their industrial application. Herein, Mn selectively doped CoP hollow microspheres are designed and synthesized to trap LiPSs and enhance Li–S reaction kinetics. Mn is successfully doped into (100) surfaces of Co3O4 via simple hydrothermal reaction, whereas it is only excessively accumulated on (111) surfaces. The unique selective doping of Mn not only provides an accurate and controllable synthesis path, but also makes synthesized target products rich in phosphorus defects after thermal shock. The adsorption, electrochemical, and in situ XRD and Raman tests prove its enhancement in adsorption capacity for LiPSs and inhibition of shuttle effect. Meanwhile, density functional theory calculations confirm that the reduced reaction energy barriers accelerate the reduction kinetics of sulfur redox conversion. Therefore, the optimal electrode displays an outstanding cycling stability with a capacity fading rate of just 0.0207% per cycle over 1000 cycles at 1 C. This study provides a novel design to promote the practical use of LSBs by introducing lattice defects, enlightening further developments of LSBs.  相似文献   

17.
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18.
    
The sp2‐hybridized nanocarbon (e.g., carbon nanotubes (CNTs) and graphene) exhibits extraordinary mechanical strength and electrical conductivity but limited external accessible surface area and a small amount of pores, while nanostructured porous carbon affords a huge surface area and abundant pore structures but very poor electrical conductance. Herein the rational hybridization of the sp2 nanocarbon and nanostructured porous carbon into hierarchical all‐carbon nanoarchitectures is demonstrated, with full inherited advantages of the component materials. The sp2 graphene/CNT interlinked networks give the composites good electrical conductivity and a robust framework, while the meso‐/microporous carbon and the interlamellar compartment between the opposite graphene accommodate sulfur and polysulfides. The strong confinement induced by micro‐/mesopores of all‐carbon nanoarchitectures renders the transformation of S8 crystal into amorphous cyclo‐S8 molecular clusters, restraining the shuttle phenomenon for high capacity retention of a lithium‐sulfur cell. Therefore, the composite cathode with an ultrahigh specific capacity of 1121 mAh g?1 at 0.5 C, a favorable high‐rate capability of 809 mAh g?1 at 10 C, a very low capacity decay of 0.12% per cycle, and an impressive cycling stability of 877 mAh g?1 after 150 cycles at 1 C. As sulfur loading increases from 50 wt% to 77 wt%, high capacities of 970, 914, and 613 mAh g?1 are still available at current densities of 0.5, 1, and 5 C, respectively. Based on the total mass of packaged devices, gravimetric energy density of GSH@APC‐S//Li cell is expected to be 400 Wh kg?1 at a power density of 10 000 W kg?1, matching the level of engine driven systems.  相似文献   

19.
    
This work compares the intercalation of K, Na, and Li in KxVPO4F (x ～ 0). The KxVPO4F (x ～ 0) cathode delivers reversible capacities of ≈90–100 mAh g?1 in K, Na, and Li cells, at an average voltage of ≈4.33 V for K, ≈3.98 V for Na, and ≈3.96 V for Li. This is so far the highest average voltage known for a K‐intercalation cathode. The lower voltage of Li insertion compared to Na is attributable to undercoordinated Li ions in the KxVPO4F (x ～ 0) framework. While the material shows high rate capability for all the alkali ions, Li migration in KxVPO4F (x ～ 0) is more difficult than with Na and K. This work suggests that a large cavity is not always good for insertion of alkali ions and cathode materials need to be suitably tailored to each intercalating ion species.  相似文献   

20.
    
Li[Ni0.65Co0.13Mn0.22]O2 cathode with two‐sloped full concentration gradient (TSFCG), maximizing the Ni content in the inner part of the particle and the Mn content near the particle surface, is synthesized via a specially designed batch‐type reactor. The cathode delivers a discharge capacity of 200 mAh g?1 (4.3 V cutoff) with excellent capacity retention of 88% after 1500 cycles in a full‐cell configuration. Overall electrochemical performance of the TSFCG cathode is benchmarked against conventional cathode (CC) with same composition and commercially available Li[Ni0.8Co0.15Al0.05]O2 (NCA). The TSFCG cathode exhibits the best cycling stability, rate capability, and thermal stability of the three electrodes. Transmission electron microscopy analysis of the cycled TSFCG, CC, and NCA cathodes shows that the TSFCG electrode maintains both its mechanical and structural integrity whereas the NCA electrode nearly pulverizes due to the strain during cycling.  相似文献   

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