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1.
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   

2.
The nonaqueous lithium oxygen battery is a promising candidate as a next‐generation energy storage system because of its potentially high energy density (up to 2–3 kW kg?1), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high energy density, long cycling stability, and low cost, the air electrode structure and the electrocatalysts play important roles. Here, a metal‐free, free‐standing macroporous graphene@graphitic carbon nitride (g‐C3N4) composite air cathode is first reported, in which the g‐C3N4 nanosheets can act as efficient electrocatalysts, and the macroporous graphene nanosheets can provide space for Li2O2 to deposit and also promote the electron transfer. The electrochemical results on the graphene@g‐C3N4 composite air electrode show a 0.48 V lower charging plateau and a 0.13 V higher discharging plateau than those of pure graphene air electrode, with a discharge capacity of nearly 17300 mA h g?1 (composite). Excellent cycling performance, with terminal voltage higher than 2.4 V after 105 cycles at 1000 mA h g?1 (composite) capacity, can also be achieved. Therefore, this hybrid material is a promising candidate for use as a high energy, long‐cycle‐life, and low‐cost cathode material for lithium oxygen batteries.  相似文献   

3.
Redox‐active catechols are bioinspired precursors for ortho ‐quinones that are characterized by higher discharge potentials than para ‐quinones, the latter being extensively used as organic cathode materials for lithium ion batteries (LIBs). Here, this study demonstrates that the rational molecular design of copolymers bearing catechol‐ and Li+ ion‐conducting anionic pendants endow redox‐active polymers (RAPs) with ultrarobust electrochemical energy storage features when combined to carbon nanotubes as a flexible, binder‐, and metal current collector‐free buckypaper electrode. The importance of the structure and functionality of the RAPs on the battery performances in LIBs is discussed. The structure‐optimized RAPs can store high‐capacities of 360 mA h g?1 at 5C and 320 mA h g?1 at 30C in LIBs. The high ion and electron mobilities within the buckypaper also enable to register 96 mA h g?1 (24% capacity retention) at an extreme C‐rate of 600C (6 s for total discharge). Moreover, excellent cyclability is noted with a capacity retention of 98% over 3400 cycles at 30C. The high capacity, superior active‐material utilization, ultralong cyclability, and excellent rate performances of RAPs‐based electrode clearly rival most of the state‐of‐the‐art Li+ ion organic cathodes, and opens up new horizons for large‐scalable fabrication of electrode materials for ultrarobust Li storage.  相似文献   

4.
Herein, a novel graphite–graphite dual ion battery (GGDIB) based on a AlCl3/1‐ethyl‐3‐methylimidazole Cl ([EMIm]Cl) room temperature ionic liquid electrolyte, using conductive graphite paper as cathode and anode material is developed. The working principle of the GGDIB is investigated, that is, metallic aluminum is deposited/dissolved on the surface of the anode, and chloroaluminate ions are intercalated/deintercalated in the cathode material. The self‐discharge phenomenon and pseudocapacitive behavior of the GGDIB are also analyzed. The GGDIB shows excellent rate performance and cycle performance due to the high ionic conductivity of ionic liquids. The initial discharge capacity is 76.5 mA h g−1 at a current density of 200 mA g−1 over a voltage window of 0.1–2.3 V, and the capacity remains at 62.3 mA h g−1 after 1000 cycles with a corresponding capacity retention of 98.42% at a current density of 500 mA g−1. With the merits of environmental friendliness and low cost, the GGDIB has a great advantage in the future of energy storage application.  相似文献   

5.
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   

6.
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   

7.
Rechargeable potassium‐ion batteries (PIBs) have attracted tremendous attention as potential electrical energy storage systems due to the special merit of abundant resources and low cost of potassium. However, one critical barrier to achieve practical application of PIBs has been the lack of suitable electrode materials. Here, a novel flexible membrane consisting of N, P codoped carbon nanofibers decorated with MoP ultrafine nanoparticles (MoP@NPCNFs) is fabricated via a simple electrospinning method combined with the later carbonization and phosphorization process. The 3D porous CNF structure in the as‐synthesized composite can shorten the transport pathways of K‐ions and improve the conductivity of electrons. The ultrafine MoP nanoparticles can guarantee high specific capacity and the N, P co‐doping could improve wettability of electrodes to electrolytes. As expected, the free‐standing MoP@NPCNF electrode demonstrates a high capacity of 320 mAh g?1 at 100 mA g?1, a superior rate capability maintaining 220 mAh g?1 at 2 A g?1, as well as a capacity retention of more than 90% even after 200 cycles. The excellent rate performance, high reversible capacity, long‐term cycling stability, and facile synthesis routine make this hybrid membrane promising anode for potassium‐ion batteries.  相似文献   

8.
Herein, 1D free‐standing and binder‐free hierarchically branched TiO2/C nanofibers (denoted as BT/C NFs) based on an in situ fabrication method as an anode for sodium‐ion batteries are reported. The in situ fabrication endows this material with large surface area and strong structural stability, providing this material with abundant active sites and smooth channels for fast ion transportation. As a result, BT/C NFs with the character of free‐standing membranes are directly used as binder‐free anode for sodium‐ion batteries, delivering a capacity of 284 mA h g?1 at a current density of 200 mA g?1 after 1000 cycles. Even at a high current density of 2000 mA g?1, the reversible capacity can still achieve as high as 204 mA h g?1. By means of kinetic analysis, it is demonstrated that the remarkable surface pseudocapacitive behavior is also a major factor to achieve excellent performance. The rationally designed structure coupled with the inherent pseudocapacitive behavior gives this material potential for sodium‐ion batteries.  相似文献   

9.
A simple and green method is developed for the preparation of nanostructured TiO2 supported on nitrogen‐doped carbon foams (NCFs) as a free‐standing and flexible electrode for lithium‐ion batteries (LIBs), in which the TiO2 with 2.5–4 times higher loading than the conventional TiO2‐based flexible electrodes acts as the active material. In addition, the NCFs act as a flexible substrate and efficient conductive networks. The nanocrystalline TiO2 with a uniform size of ≈10 nm form a mesoporous layer covering the wall of the carbon foam. When used directly as a flexible electrode in a LIB, a capacity of 188 mA h g?1 is achieved at a current density of 200 mA g?1 for a potential window of 1.0–3.0 V, and a specific capacity of 149 mA h g?1 after 100 cycles at a current density of 1000 mA g?1 is maintained. The highly conductive NCF and flexible network, the mesoporous structure and nanocrystalline size of the TiO2 phase, the firm adhesion of TiO2 over the wall of the NCFs, the small volume change in the TiO2 during the charge/discharge processes, and the high cut‐off potential contribute to the excellent capacity, rate capability, and cycling stability of the TiO2/NCFs flexible electrode.  相似文献   

10.
Incorporation of N,S‐codoped nanotube‐like carbon (N,S‐NTC) can endow electrode materials with superior electrochemical properties owing to the unique nanoarchitecture and improved kinetics. Herein, α‐MnS nanoparticles (NPs) are in situ encapsulated into N,S‐NTC, preparing an advanced anode material (α‐MnS@N,S‐NTC) for lithium‐ion/sodium‐ion batteries (LIBs/SIBs). It is for the first time revealed that electrochemical α → β phase transition of MnS NPs during the 1st cycle effectively promotes Li‐storage properties, which is deduced by the studies of ex situ X‐ray diffraction/high‐resolution transmission electron microscopy and electrode kinetics. As a result, the optimized α‐MnS@N,S‐NTC electrode delivers a high Li‐storage capacity (1415 mA h g?1 at 50 mA g?1), excellent rate capability (430 mA h g?1 at 10 A g?1), and long‐term cycling stability (no obvious capacity decay over 5000 cycles at 1 A g?1) with retained morphology. In addition, the N,S‐NTC‐based encapsulation plays the key roles on enhancing the electrochemical properties due to its high conductivity and unique 1D nanoarchitecture with excellent protective effects to active MnS NPs. Furthermore, α‐MnS@N,S‐NTC also delivers high Na‐storage capacity (536 mA h g?1 at 50 mA g?1) without the occurrence of such α → β phase transition and excellent full‐cell performances as coupling with commercial LiFePO4 and LiNi0.6Co0.2Mn0.2O2 cathodes in LIBs as well as Na3V2(PO4)2O2F cathode in SIBs.  相似文献   

11.
The development of manganese dioxide as the cathode for aqueous Zn‐ion battery (ZIB) is limited by the rapid capacity fading and material dissolution. Here, a highly reversible aqueous ZIB using graphene scroll‐coated α‐MnO2 as the cathode is proposed. The graphene scroll is uniformly coated on the MnO2 nanowire with an average width of 5 nm, which increases the electrical conductivity of the MnO2 nanowire and relieves the dissolution of the cathode material during cycling. An energy density of 406.6 Wh kg?1 (382.2 mA h g?1) at 0.3 A g?1 can be reached, which is the highest specific energy value among all the cathode materials for aqueous Zn‐ion battery so far, and good long‐term cycling stability with 94% capacity retention after 3000 cycles at 3 A g?1 are achieved. Meanwhile, a two‐step intercalation mechanism that Zn ions first insert into the layers and then the tunnels of MnO2 framework is proved by in situ X‐ray diffraction, galvanostatic intermittent titration technique, and X‐ray photoelectron spectroscopy characterizations. The graphene scroll‐coated metallic oxide strategy can also bring intensive interests for other energy storage systems.  相似文献   

12.
Magnesium-ion batteries (MIBs) are emerging as potential next-generation energy storage systems due to high security and high theoretical energy density. Nevertheless, the development of MIBs is limited by the lack of cathode materials with high specific capacity and cyclic stability. Currently, transition metal sulfides are considered as a promising class of cathode materials for advanced MIBs. Herein, a template-based strategy is proposed to successfully fabricate metal-organic framework-derived in-situ porous carbon nanorod-encapsulated CuS quantum dots (CuS-QD@C nanorods) via a two-step method of sulfurization and cation exchange. CuS quantum dots have abundant electrochemically active sites, which facilitate the contact between the electrode and the electrolyte. In addition, the tight combination of CuS quantum dots and porous carbon nanorods increases the electronic conductivity while accelerating the transport speed of ions and electrons. With these architectural and compositional advantages, when used as a cathode material for MIBs, the CuS-QD@C nanorods exhibit remarkable performance in magnesium storage, including a high reversible capacity of 323.7 mAh g−1 at 100 mA g−1 after 100 cycles, excellent long-term cycling stability (98.5 mAh g−1 after 1000 cycles at 1.0 A g−1), and satisfying rate performance (111.8 mA g−1 at 1.0 A g−1).  相似文献   

13.
Novel electrode materials consisting of hollow cobalt sulfide nanoparticles embedded in graphitic carbon nanocages (HCSP?GCC) are facilely synthesized by a top‐down route applying room‐temperature synthesized Co‐based zeolitic imidazolate framework (ZIF‐67) as the template. Owing to the good mechanical flexibility and pronounced structure stability of carbon nanocages‐encapsulated Co9S8, the as‐obtained HCSP?GCC exhibit superior Li‐ion storage. Working in the voltage of 1.0?3.0 V, they display a very high energy density (707 Wh kg?1), superior rate capability (reversible capabilities of 536, 489, 438, 393, 345, and 278 mA h g?1 at 0.2, 0.5, 1, 2, 5, and 10C, respectively), and stable cycling performance (≈26% capacity loss after long 150 cycles at 1C with a capacity retention of 365 mA h g?1). When the work voltage is extended into 0.01–3.0 V, a higher stable capacity of 1600 mA h g?1 at a current density of 100 mA g?1 is still achieved.  相似文献   

14.
Rechargeable aqueous zinc–ion batteries have offered an alternative for large‐scale energy storage owing to their low cost and material abundance. However, developing suitable cathode materials with excellent performance remains great challenges, resulting from the high polarization of zinc ion. In this work, an aqueous zinc–ion battery is designed and constructed based on H2V3O8 nanowire cathode, Zn(CF3SO3)2 aqueous electrolyte, and zinc anode, which exhibits the capacity of 423.8 mA h g−1 at 0.1 A g−1, and excellent cycling stability with a capacity retention of 94.3% over 1000 cycles. The remarkable electrochemical performance is attributed to the layered structure of H2V3O8 with large interlayer spacing, which enables the intercalation/de‐intercalation of zinc ions with a slight change of the structure. The results demonstrate that exploration of the materials with large interlayer spacing is an effective strategy for improving electrochemical stability of electrodes for aqueous Zn ion batteries.  相似文献   

15.
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   

16.
Selenium cathode has attracted more and more attention because of its comparable volumetric capacity but much higher electrical conductivity than sulfur cathode. Compared to Li–Se batteries, Na–Se batteries show many advantages, including the low cost of sodium resources and high volumetric capacity. However, Na–Se batteries still suffer from the shuttle effect of polyselenides and high volumetric expansion, resulting in the poor electrochemical performance. Herein, Se is impregnated into microporous multichannel carbon nanofibers (Se@MCNFs) thin film with high flexibility as a binder‐free cathode material for Na–Se batteries. The fibrous unique structure of the Se@MCNFs is beneficial to alleviate the volume change of Se during cycling, improve the utilization of active material, and suppress the dissolution of polyselenides into electrolyte. The freestanding Se@MCNF thin‐film electrode exhibits high discharge capacity (596 mA h g?1 at the 100th cycle at 0.1 A g?1) and excellent rate capability (379 mA h g?1 at 2 A g?1) for Na–Se batteries. In addition, it also shows long cycle life with a negligible capacity decay of 0.067% per cycle over 300 cycles at 0.5 A g?1. This work demonstrates the possibility to develop high performance Na–Se batteries and flexible energy storage devices.  相似文献   

17.
The capacity and conductivity deficiencies of TiO2(B) are addressed simultaneously through a smart morphological and compositional design. Elaborately designed hierarchical heterostructures are reported, consisting of carbon‐coated TiO2(B) nanosheets decorated with Fe3O4 nanoparticles, based on a facile self‐assembly strategy. The novel hierarchical heterostructures exhibit a remarkable synergy by bridging the intriguing functionalities of TiO2(B) nanosheets (high safety and durability), Fe3O4 nanoparticles (high theoretical capacity), and carbon coatings (high conductivity), which results in significantly improved cycle and rate performances. A startlingly high reversible capacity of 763 mA h g−1 is delivered at 500 mA g−1 after 200 charging−discharging cycles. Even when the current density is as high as 10 000 mA g−1, the reversible capacity is still up to 498 mA h g−1. This smart morphological and compositional design opens up new opportunities for developing novel, multifunctional hierarchical heterostructures as promising anode materials for next‐generation, high‐power lithium‐ion batteries.  相似文献   

18.
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   

19.
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   

20.
In the present work, a hierarchical composite of rose‐like VS2@S/N‐doped carbon (VS2@SNC) with expanded (001) planes is successfully fabricated through a facile synthetic route. Notably, the d‐spacing of (001) planes is expanded to 0.92 nm, which is proved to dramatically reduce the energy barrier for Li+ diffusion in the composite of VS2@SNC by density functional theory calculation. On the other hand, the S/N‐doped carbon in the composite greatly promotes the electrical conductivity and enhances the structural stability. In addition, the hierarchical structure of VS2@SNC facilitates rapid electrolyte diffusion and increases the contact area between the electrode and electrolyte simultaneously. Benefiting from the merits mentioned above, the VS2@SNC electrode exhibits excellent electrochemical properties, such as a large reversible capacity of 971.6 mA h g?1 at 0.2 A g?1, an extremely high rate capability of 772.1 mA h g?1 at 10 A g?1, and a remarkable cycling stability up to 600 cycles at 8 A g?1 with a capacity of 684.5 mA h g?1, making it a promising candidate as an anode material for lithium‐ion batteries.  相似文献   

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