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1.
Selenium (Se)‐based rechargeable aluminum batteries (RABs), known as aluminum–selenium (Al–Se) batteries, are an appealing new battery design that holds great promise for addressing the low‐capacity problem of current RAB technology. However, their applications are hindered by mediocre high‐rate capacity (≈100 mAh g?1 at 0.5 A g?1) and insufficient cycling life (50 cycles). Herein, the synthesis of mesoporous carbon fibers (MCFs) by coating mesoporous carbon with short‐length mesopores and tunable mesopore sizes (2.7 to 8.9 nm) coaxially on carbon nanotubes (CNT) is reported. When compositing MCFs with Se for Al–Se batteries, a positive correlation between mesopore size and electrolyte ion diffusivity is observed, however when pore size is increased to 8.9 nm, large voids are created at the interface of CNT core and mesoporous carbon shell, leading to decreased electrode conductivity. The trade‐off between ion diffusivity and interfacial connectivity/conductivity determines MCF with pore size of 7.1 nm as the best host material for Al–Se batteries. The composite cathode delivers high specific capacities (366 and 230 mAh g?1 at 0.5 and 1 A g?1), good rate performance, and excellent cycling stability (152 mAh g?1 after 500 cycles at 2 A g?1), superior over previously reported Se cathodes and other cathodes for RABs.  相似文献   

2.
Owing to high energy capacities, transition metal chalcogenides have drawn significant research attention as the promising electrode materials for sodium‐ion batteries (SIBs). However, limited cycle life and inferior rate capabilities still hinder their practical application. Improvement of the intrinsic conductivity by smart choice of elemental combination along with carbon coupling of the nanostructures may result in excellence of rate capability and prolonged cycling stability. Herein, a hierarchically porous binary transition metal selenide (Fe2CoSe4, termed as FCSe) nanomaterial with improved intrinsic conductivity was prepared through an exclusive methodology. The hierarchically porous structure, intimate nanoparticle–carbon matrix contact, and better intrinsic conductivity result in extraordinary electrochemical performance through their synergistic effect. The synthesized FCSe exhibits excellent rate capability (816.3 mA h g?1 at 0.5 A g?1 and 400.2 mA h g?1 at 32 A g?1), extended cycle life (350 mA h g?1 even after 5000 cycles at 4 A g?1), and adequately high energy capacity (614.5 mA h g?1 at 1 A g?1 after 100 cycles) as anode material for SIBs. When further combined with lab‐made Na3V2(PO4)3/C cathode in Na‐ion full cells, FCSe presents reasonably high and stable specific capacity.  相似文献   

3.
Lithium–oxygen (Li–O2) batteries are attracting more attention owing to their superior theoretical energy density compared to conventional Li‐ion battery systems. With regards to the catalytically electrochemical reaction on a cathode, the electrocatalyst plays a key role in determining the performance of Li–O2 batteries. Herein, a new 3D hollow α‐MnO2 framework (3D α‐MnO2) with porous wall assembled by hierarchical α‐MnO2 nanowires is prepared by a template‐induced hydrothermal reaction and subsequent annealing treatment. Such a distinctive structure provides some essential properties for Li–O2 batteries including the intrinsic high catalytic activity of α‐MnO2, more catalytic active sites of hierarchical α‐MnO2 nanowires on 3D framework, continuous hollow network and rich porosity for the storage of discharge product aggregations, and oxygen diffusion. As a consequence, 3D α‐MnO2 achieves a high specific capacity of 8583 mA h g?1 at a current density of 100 mA g?1, a superior rate capacity of 6311 mA h g?1 at 300 mA g?1, and a very good cycling stability of 170 cycles at a current density of 200 mA g?1 with a fixed capacity of 1000 mA h g?1. Importantly, the presented design strategy of 3D hollow framework in this work could be extended to other catalytic cathode design for Li–O2 batteries.  相似文献   

4.
Mg batteries have the advantages of resource abundance, high volumetric energy density, and dendrite‐free plating/stripping of Mg anodes. However the injection of highly polar Mg2+ cannot maintain the structural integrity of intercalation‐type cathodes even for open framework prototypes. The lack of high‐voltage electrolytes and sluggish Mg2+ diffusion in lattices or through interfaces also limit the energy density of Mg batteries. Mg–S system based on moderate‐voltage conversion electrochemistry appears to be a promising solution to high‐energy Mg batteries. However, it still suffers from poor capacity and cycling performances so far. Here, a ZIF‐67 derivative carbon framework codoped by N and Co atoms is proposed as effective S host for highly reversible Mg–S batteries even under high rates. The discharge capacity is as high as ≈600 mA h g?1 at 1 C during the first cycle, and it is still preserved at ≈400 mA h g?1 after at least 200 cycles. Under a much higher rate of 5 C, a capacity of 300–400 mA h g?1 is still achievable. Such a superior performance is unprecedented among Mg–S systems and benefits from multiple factors, including heterogeneous doping, Li‐salt and Cl? addition, charge mode, and cut‐off capacity, as well as separator decoration, which enable the mitigation of electrode passivation and polysulfide loss.  相似文献   

5.
Flexible power sources have shown great promise in next‐generation bendable, implantable, and wearable electronic systems. Here, flexible and binder‐free electrodes of Na3V2(PO4)3/reduced graphene oxide (NVP/rGO) and Sb/rGO nanocomposites for sodium‐ion batteries are reported. The Sb/rGO and NVP/rGO paper electrodes with high flexibility and tailorability can be easily fabricated. Sb and NVP nanoparticles are embedded homogenously in the interconnected framework of rGO nanosheets, which provides structurally stable hosts for Na‐ion intercalation and deintercalation. The NVP/rGO paper‐like cathode delivers a reversible capacity of 113 mAh g?1 at 100 mA g?1 and high capacity retention of ≈96.6% after 120 cycles. The Sb/rGO paper‐like anode gives a highly reversible capacity of 612 mAh g?1 at 100 mA g?1, an excellent rate capacity up to 30 C, and a good cycle performance. Moreover, the sodium‐ion full cell of NVP/rGO//Sb/rGO has been fabricated, delivering a highly reversible capacity of ≈400 mAh g?1 at a current density of 100 mA g?1 after 100 charge/discharge cycles. This work may provide promising electrode candidates for developing next‐generation energy‐storage devices with high capacity and long cycle life.  相似文献   

6.
A sulfur‐linked carbonyl‐based poly(2,5‐dihydroxyl‐1,4‐benzoquinonyl sulfide) (PDHBQS) compound is synthesized and used as cathode material for lithium‐ion batteries (LIBs). Flexible binder‐free composite cathode with single‐wall carbon nanotubes (PDHBQS–SWCNTs) is then fabricated through vacuum filtration method with SWCNTs. Electrochemical measurements show that PDHBQS–SWCNTs cathode can deliver a discharge capacity of 182 mA h g−1 (0.9 mA h cm−2) at a current rate of 50 mA g−1 and a potential window of 1.5 V–3.5 V. The cathode delivers a capacity of 75 mA h g−1 (0.47 mA h cm−2) at 5000 mA g−1, which confirms its good rate performance at high current density. PDHBQS–SWCNTs flexible cathode retains 89% of its initial capacity at 250 mA g−1 after 500 charge–discharge cycles. Furthermore, large‐area (28 cm2) flexible batteries based on PDHBQS–SWCNTs cathode and lithium foils anode are also assembled. The flexible battery shows good electrochemical activities with continuous bending, which retains 88% of its initial discharge capacity after 2000 bending cycles. The significant capacity, high rate performance, superior cyclic performance, and good flexibility make this material a promising candidate for a future application of flexible LIBs.  相似文献   

7.
Sulfur cathodes have become appealing for rechargeable batteries because of their high theoretical capacity (1675 mA h g?1). However, the conventional cathode configuration borrowed from lithium‐ion batteries may not allow the pure sulfur cathode to put its unique materials chemistry to good use. The solid(sulfur)–liquid(polysulfides)–solid(sulfides) phase transitions generate polysulfide intermediates that are soluble in the commonly used organic solvents in Li–S cells. The resulting severe polysulfide diffusion and the irreversible active‐material loss have been hampering the development of Li–S batteries for years. The present study presents a robust, ultra‐tough, flexible cathode with the active‐material fillings encapsulated between two buckypapers (B), designated as buckypaper/sulfur/buckypaper (B/S/B) cathodes, that suppresses the irreversible polysulfide diffusion to the anode and offers excellent electrochemical reversibility with a low capacity fade rate of 0.06% per cycle after 400 cycles. Engineering enhancements demonstrate that the B/S/B cathodes represent a facile approach for the development of high‐performance sulfur electrodes with a high areal capacity of 5.1 mA h cm?2, which increases further to approach 7 mA h cm?2 on coupling with carbon‐coated separators.  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.
Potassium‐ion batteries have attracted increasing attention for next‐generation energy storage systems due to their high energy density and abundance of potassium. However, the lack of suitable anode highly hampers its practical application due to the large ionic radius of K+. Herein, a Se3P4@mesoporous carbon (Se3P4@C) composite is reported as a high‐performance anode for potassium‐ion batteries. The Se3P4@C composite is synthesized through an in situ combination reaction between red phosphorus and Se within a porous carbon matrix. In this way, the nano‐sized Se3P4 is well confined in the porous carbon and thus exhibits a close contact with the carbon matrix. This can significantly improve the conductivity and alleviate the volume change during the cycling process. As a result, the Se3P4@C exhibits a high reversible initial capacity of 1036.8 mAh g?1 at a current density of 50 mA g?1 as well as an excellent cycle performance with a capacity decay of 0.07% per cycle over 300 cycles under 1000 mA g?1. In terms of high specific capacity and stable cycling performance, the Se3P4@C anode is a promising candidate for advanced potassium‐ion batteries.  相似文献   

10.
Prussian blue and its analogs are regarded as the promising cathodes for sodium‐ion batteries (SIBs). Recently, various special structures are constructed to improve the electrochemical properties of these materials. In this study, a novel architecture of Prussian blue analogs with large cavity and multilayer shells is investigated as cathode material for SIBs. Because the hollow structure can relieve volume expansion and core–shell heterostructure can optimize interfacial properties, the complex structure materials exhibited a highly initial capacity of 123 mA h g?1 and a long cycle life. After 600 cycles, the reversible capacity of the electrode still maintains at 102 mA h g?1 without significant voltage decay, indicating a superior structure stability and sodium storage kinetics. Even at high current density of 3200 mA g?1, the electrode still delivers a considerable capacity above 52 mA h g?1. According to the electrochemical analysis and ex‐situ measurements, it can be inferred that the enhanced apparent diffusion coefficient and improved insertion/extraction performance of electrode have been obtained by building this new morphology.  相似文献   

11.
The primary challenge with lithium–sulfur battery research is the design of sulfur cathodes that exhibit high electrochemical efficiency and stability while keeping the sulfur content and loading high and the electrolyte/sulfur ratio low. With a systematic investigation, a novel graphene/cotton‐carbon cathode is presented here that enables sulfur loading and content as high as 46 mg cm?2 and 70 wt% with an electrolyte/sulfur ratio of as low as only 5. The graphene/cotton‐carbon cathodes deliver peak capacities of 926 and 765 mA h g?1, respectively, at C/10 and C/5 rates, which translate into high areal, gravimetric, and volumetric capacities of, respectively, 43 and 35 mA h cm?2, 648 and 536 mA h g?1, and 1067 and 881 mA h cm?3 with a stable cyclability. They also exhibit superior cell‐storage capability with 95% capacity‐retention, a low self‐discharge constant of just 0.0012 per day, and stable poststorage cyclability after storing over a long period of six months. This work demonstrates a viable approach to develop lithium–sulfur batteries with practical energy densities exceeding that of lithium‐ion batteries.  相似文献   

12.
For the first time a new strategy is reported to improve the volumetric capacity and Coulombic efficiency by selenium doping for lithium–organosulfur batteries. Selenium‐doped cathodes with four sulfur atoms and one selenium atom (as the doped heteroatom) in the confined structure are designed and synthesized; this structure exhibits greatly improved volumetric/areal capacities, and a Coulombic efficiency of almost 100% for highly stable lithium–organosulfur batteries. The doping of Se significantly enhances the electronic conductivity of battery electrodes by a factor of 6.2 compared to pure sulfur electrodes, and completely restricts the production of long‐chain lithium polysulfides. This allows achievement of a high gravimetric capacity of 700 mAh g?1 close to its theoretical mass capacity, an exceptional volumetric capacity of 2457 mAh cm?3, and excellent capacity retention of 92% after 400 cycles. Shuttle effect is efficiently weakened since no long‐chain polysulfides are detected from in situ UV/vis results throughout the entire cycling process arising from selenium doping, which is theoretically confirmed by density functional theory calculations.  相似文献   

13.
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   

14.
Conventional lithium–sulfur batteries often suffer from fatal problems such as high flammability, polysulfide shuttling, and lithium dendrites growth. Here, highly‐safe lithium–sulfur batteries based on flame‐retardant electrolyte (dimethoxyether/1,1,2,2‐tetrafluoroethyl 2,2,3,3‐tetrafluoropropyl ether) coupled with functional separator (nanoconductive carbon‐coated cellulose nonwoven) to resolve aforementioned bottle‐neck issues are demonstrated. It is found that this flame‐retardant electrolyte exhibits excellent flame retardancy and low solubility of polysulfide. In addition, Li/Li symmetrical cells using such flame‐retardant electrolyte deliver extraordinary long‐term cycling stability (less than 10 mV overpotential) for over 2500 h at 1.0 mA cm?2 and 1.0 mAh cm?2. Moreover, bare sulfur cathode–based lithium–sulfur batteries using this flame retardant electrolyte coupled with nanoconductive carbon‐coated cellulose separator can retain 83.6% discharge capacity after 200 cycles at 0.5 C. Under high charge/discharge rate (4 C), lithium–sulfur cells still show high charge/discharge capacity of ≈350 mAh g?1. Even at an elevated temperature of 60 °C, discharge capacity of 870 mAh g?1 can be retained. More importantly, high‐loading bare sulfur cathode (4 mg cm?2)–based lithium–sulfur batteries can also deliver high charge/discharge capacity over 806 mAh g?1 after 56 cycles. Undoubtedly, the strategy of flame retardant electrolyte coupled with carbon‐coated separator enlightens highly safe lithium–sulfur batteries at a wide range of temperature.  相似文献   

15.
It is of great importance to develop cost‐effective electrode materials for large‐scale use of Na‐ion batteries. Here, a binder‐free electrode based on necklace‐like structures composed of Fe3N@C yolk–shell particles as an advanced anode for Na‐ion batteries is reported. In this electrode, every Fe3N@C unit has a novel yolk–shell structure, which can accommodate the volumetric changes of Fe3N during the (de)sodiation processes for superior structural integrity. Moreover, all reaction units are threaded along the carbon fibers, guaranteeing excellent kinetics for the electrochemical reactions. As a result, when evaluated as an anode material for Na‐ion batteries, the Fe3N@C nano‐necklace electrode delivers a prolonged cycle life over 300 cycles, and achieves a high C‐rate capacity of 248 mAh g?1 at 2 A g?1.  相似文献   

16.
The large‐scale application of sodium/potassium‐ion batteries is severely limited by the low and slow charge storage dynamics of electrode materials. The crystalline carbons exhibit poor insertion capability of large Na+/K+ ions, which limits the storage capability of Na/K batteries. Herein, porous S and N co‐doped thin carbon (S/N@C) with shell‐like (shell size ≈20–30 nm, shell wall ≈8–10 nm) morphology for enhanced Na+/K+ storage is presented. Thanks to the hollow structure and thin shell‐wall, S/N@C exhibits an excellent Na+/K+ storage capability with fast mass transport at higher current densities, leading to limited compromise over charge storage at high charge/discharge rates. The S/N@C delivers a high reversible capacity of 448 mAh g‐1 for Na battery, at the current density of 100 mA g‐1 and maintains a discharge capacity up to 337 mAh g‐1 at 1000 mA g‐1. Owing to shortened diffusion pathways, S/N@C delivers an unprecedented discharge capacity of 204 and 169 mAh g‐1 at extremely high current densities of 16 000 and 32 000 mA g‐1, respectively, with excellent reversible capacity for 4500 cycles. Moreover, S/N@C exhibits high K+ storage capability (320 mAh g‐1 at current density of 50 mA g‐1) and excellent cyclic life.  相似文献   

17.
Sodium‐ion batteries (SIBs) are still confronted with several major challenges, including low energy and power densities, short‐term cycle life, and poor low‐temperature performance, which severely hinder their practical applications. Here, a high‐voltage cathode composed of Na3V2(PO4)2O2F nano‐tetraprisms (NVPF‐NTP) is proposed to enhance the energy density of SIBs. The prepared NVPF‐NTP exhibits two high working plateaux at about 4.01 and 3.60 V versus the Na+/Na with a specific capacity of 127.8 mA h g?1. The energy density of NVPF‐NTP reaches up to 486 W h kg?1, which is higher than the majority of other cathode materials previously reported for SIBs. Moreover, due to the low strain (≈2.56% volumetric variation) and superior Na transport kinetics in Na intercalation/extraction processes, as demonstrated by in situ X‐ray diffraction, galvanostatic intermittent titration technique, and cyclic voltammetry at varied scan rates, the NVPF‐NTP shows long‐term cycle life, superior low‐temperature performance, and outstanding high‐rate capabilities. The comparison of Ragone plots further discloses that NVPF‐NTP presents the best power performance among the state‐of‐the‐art cathode materials for SIBs. More importantly, when coupled with an Sb‐based anode, the fabricated sodium‐ion full‐cells also exhibit excellent rate and cycling performances, thus providing a preview of their practical application.  相似文献   

18.
In this work, combining both advantages of potassium‐ion batteries and dual‐ion batteries, a novel potassium‐ion‐based dual‐ion battery (named as K‐DIB) system is developed based on a potassium‐ion electrolyte, using metal foil (Sn, Pb, K, or Na) as anode and expanded graphite as cathode. When using Sn foil as the anode, the K‐DIB presents a high reversible capacity of 66 mAh g?1 at a current density of 50 mA g?1 over the voltage window of 3.0–5.0 V, and exhibits excellent long‐term cycling performance with 93% capacity retention for 300 cycles. Moreover, as the Sn foil simultaneously acts as the anode material and the current collector, dead load and dead volume of the battery can be greatly reduced, thus the energy density of the K‐DIB is further improved. It delivers a high energy density of 155 Wh kg?1 at a power density of 116 W kg?1, which is comparable with commercial lithium‐ion batteries. Thus, with the advantages of environmentally friendly, cost effective, and high energy density, this K‐DIB shows attractive potential for future energy storage application.  相似文献   

19.
Lithium–sulfur (Li–S) batteries are investigated intensively as a promising large‐scale energy storage system owing to their high theoretical energy density. However, the application of Li–S batteries is prevented by a series of primary problems, including low electronic conductivity, volumetric fluctuation, poor loading of sulfur, and shuttle effect caused by soluble lithium polysulfides. Here, a novel composite structure of sulfur nanoparticles attached to porous‐carbon nanotube (p‐CNT) encapsulated by hollow MnO2 nanoflakes film to form p‐CNT@Void@MnO2/S composite structures is reported. Benefiting from p‐CNTs and sponge‐like MnO2 nanoflake film, p‐CNT@Void@MnO2/S provides highly efficient pathways for the fast electron/ion transfer, fixes sulfur and Li2S aggregation efficiently, and prevents polysulfide dissolution during cycling. Besides, the additional void inside p‐CNT@Void@MnO2/S composite structure provides sufficient free space for the expansion of encapsulated sulfur nanoparticles. The special material composition and structural design of p‐CNT@Void@MnO2/S composite structure with a high sulfur content endow the composite high capacity, high Coulombic efficiency, and an excellent cycling stability. The capacity of p‐CNT@Void@MnO2/S electrode is ≈599.1 mA h g?1 for the fourth cycle and ≈526.1 mA h g?1 after 100 cycles, corresponding to a capacity retention of ≈87.8% at a high current density of 1.0 C.  相似文献   

20.
Abstract

Aluminum-ion batteries are favorable for the next generation of rechargeable batteries by virtue of their high theoretical energy density, high safety and low cost. Graphite with excellent electronic conductivity and large surface area is likely to be the most pleasurable cathode material for aluminum-ion batteries. However, due to the lack of high-performance cathodes and cost-effective electrolytes, aluminum-ion batteries are greatly hindered. Herein, a nitrogen doped three-dimensional porous carbon material cathode (N-3PC) with controlled porous and disordered structures is synthesized via a facile heating reaction in oil bath combined with sintering method. Moreover, the controlled porous structures by the Zn(NO3)2 pore-forming agent method support a very large specific surface area, which is beneficial to a relatively high initial Coulombic efficiency. In terms of open porous structures of N-3PC, the increased disordered structures can not only benefit the diffusion of Al3+ ions but also enlarge the reversible capacity of Al storage. When applied as cathode materials for aluminum-ion batteries, N-3PC cathode showcases rosy rate capability (33?mA h g?1 at 500?mA g?1) and perfect reversible capacity (13?mA h g?1 at a high current density of 2000?mA g?1). Furthermore, the high-performance N-3PC cathode material is prepared via a green approach stemming from low-cost and Zn(NO3)2 template, demonstrating a feasible development of carbon cathode materials for aluminum-ion batteries.  相似文献   

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