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1.
Lithium‐ion batteries are receiving considerable attention for large‐scale energy‐storage systems. However, to date the current cathode/anode system cannot satisfy safety, cost, and performance requirements for such applications. Here, a lithium‐ion full battery based on the combination of a Li3VO4 anode with a LiNi0.5Mn1.5O4 cathode is reported, which displays a better performance than existing systems. Carbon‐coated Li3VO4 spheres comprising nanoscale carbon‐coating primary particles are synthesized by a morphology‐inheritance route. The observed high capacity combined with excellent sample stability and high rate capability of carbon‐coated Li3VO4 spheres is superior to other insertion anode materials. A high‐performance full lithium‐ion battery is fabricated by using the carbon‐coated Li3VO4 spheres as the anode and LiNi0.5Mn1.5O4 spheres as the cathode; such a cell shows an estimated practical energy density of 205 W h kg?1 with greatly improved properties such as pronounced long‐term cyclability, and rapid charge and discharge.  相似文献   

2.
High‐performance of lithium‐ion batteries (LIBs) rely largely on the scrupulous design of nanoarchitectures and smart hybridization of bespoke active materials. In this work, the pine‐needle‐like Cu–Co skeleton is reported to support highly active Li4Ti5O12 (LTO) forming Cu–Co/LTO core–branch arrays via a united hydrothermal‐atomic layer deposition (ALD) method. ALD‐formed LTO layer is uniformly anchored on the pine‐needle‐like heterostructured Cu–Co backbone, which consists of branched Co nanowires (diameters in 20 nm) and Cu nanowires (250–300 nm) core. The designed Cu–Co/LTO core–branch arrays show combined advantages of large porosity, high electrical conductivity, and good adhesion. Due to the unique positive features, the Cu–Co/LTO electrodes are demonstrated with enhanced electrochemical performance including excellent high‐rate capacity (155 mAh g?1 at 20 C) and noticeable long‐term cycles (144 mAh g?1 at 20 C after 3000 cycles). Additionally, the full cell assembled with activated carbon positive electrode and Cu–Co/LTO negative electrode exhibits high power/energy densities (41.6 Wh kg?1 at 7.5 kW kg?1). The design protocol combining binder‐free characteristics and array configuration opens a new door for construction of advanced electrodes for application in high‐rate electrochemical energy storage.  相似文献   

3.
A high capacity cathode is the key to the realization of high‐energy‐density lithium‐ion batteries. The anionic oxygen redox induced by activation of the Li2MnO3 domain has previously afforded an O3‐type layered Li‐rich material used as the cathode for lithium‐ion batteries with a notably high capacity of 250–300 mAh g?1. However, its practical application in lithium‐ion batteries has been limited due to electrodes made from this material suffering severe voltage fading and capacity decay during cycling. Here, it is shown that an O2‐type Li‐rich material with a single‐layer Li2MnO3 superstructure can deliver an extraordinary reversible capacity of 400 mAh g?1 (energy density: ≈1360 Wh kg?1). The activation of a single‐layer Li2MnO3 enables stable anionic oxygen redox reactions and leads to a highly reversible charge–discharge cycle. Understanding the high performance will further the development of high‐capacity cathode materials that utilize anionic oxygen redox processes.  相似文献   

4.
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   

5.
Flexible supercapacitors have shown enormous potential for portable electronic devices. Herein, hierarchical 3D all‐carbon electrode materials are prepared by assembling N‐doped graphene quantum dots (N‐GQDs) on carbonized MOF materials (cZIF‐8) interweaved with carbon nanotubes (CNTs) for flexible all‐solid‐state supercapacitors. In this ternary electrode, cZIF‐8 provides a large accessible surface area, CNTs act as the electrical conductive network, and N‐GQDs serve as highly pseudocapactive materials. Due to the synergistic effect and hierarchical assembly of these components, N‐GQD@cZIF‐8/CNT electrodes exhibit a high specific capacitance of 540 F g?1 at 0.5 A g?1 in a 1 m H2SO4 electrolyte and excellent cycle stability with 90.9% capacity retention over 8000 cycles. The assembled supercapacitor possesses an energy density of 18.75 Wh kg?1 with a power density of 108.7 W kg?1. Meanwhile, three supercapacitors connected in series can power light‐emitting diodes for 20 min. All‐solid‐state N‐GQD@cZIF‐8/CNT flexible supercapacitor exhibits an energy density of 14 Wh kg?1 with a power density of 89.3 W kg?1, while the capacitance retention after 5000 cycles reaches 82%. This work provides an effective way to construct novel electrode materials with high energy storage density as well as good cycling performance and power density for high‐performance energy storage devices via the rational design.  相似文献   

6.
The major challenges faced by candidate electrode materials in lithium‐ion batteries (LIBs) include their low electronic and ionic conductivities. 2D van der Waals materials with good electronic conductivity and weak interlayer interaction have been intensively studied in the electrochemical processes involving ion migrations. In particular, molybdenum ditelluride (MoTe2) has emerged as a new material for energy storage applications. Though 2H‐MoTe2 with hexagonal semiconducting phase is expected to facilitate more efficient ion insertion/deinsertion than the monoclinic semi‐metallic phase, its application as an anode in LIB has been elusive. Here, 2H‐MoTe2, prepared by a solid‐state synthesis route, has been employed as an efficient anode with remarkable Li+ storage capacity. The as‐prepared 2H‐MoTe2 electrodes exhibit an initial specific capacity of 432 mAh g?1 and retain a high reversible specific capacity of 291 mAh g?1 after 260 cycles at 1.0 A g?1. Further, a full‐cell prototype is demonstrated by using 2H‐MoTe2 anode with lithium cobalt oxide cathode, showing a high energy density of 454 Wh kg?1 (based on the MoTe2 mass) and capacity retention of 80% over 100 cycles. Synchrotron‐based in situ X‐ray absorption near‐edge structures have revealed the unique lithium reaction pathway and storage mechanism, which is supported by density functional theory based calculations.  相似文献   

7.
Lithium‐ion capacitors (LICs) are promising electrical energy storage systems for mid‐to‐large‐scale applications due to the high energy and large power output without sacrificing long cycle stability. However, due to the different energy storage mechanisms between anode and cathode, the energy densities of LICs often degrade noticeably at high power density, because of the sluggish kinetics limitation at the battery‐type anode side. Herein, a high‐performance LIC by well‐defined ZnMn2O4‐graphene hybrid nanosheets anode and N‐doped carbon nanosheets cathode is presented. The 2D nanomaterials offer high specific surface areas in favor of a fast ion transport and storage with shortened ion diffusion length, enabling fast charge and discharge. The fabricated LIC delivers a high specific energy of 202.8 Wh kg?1 at specific power of 180 W kg?1, and the specific energy remains 98 Wh kg?1 even when the specific power achieves as high as 21 kW kg?1.  相似文献   

8.
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   

9.
Omnibearing acceleration of charge/ion transfer in Li4Ti5O12 (LTO) electrodes is of great significance to achieve advanced high‐rate anodes in lithium‐ion batteries. Here, a synergistic combination of hydrogenated LTO nanoparticles (H‐LTO) and N‐doped carbon fibers (NCFs) prepared by an electrodeposition‐atomic layer deposition method is reported. Binder‐free conductive NCFs skeletons are used as strong support for H‐LTO, in which Ti3+ is self‐doped along with oxygen vacancies in LTO lattice to realize enhanced intrinsic conductivity. Positive advantages including large surface area, boosted conductivity, and structural stability are obtained in the designed H‐LTO@NCF electrode, which is demonstrated with preeminent high‐rate capability (128 mAh g?1 at 50 C) and long cycling life up to 10 000 cycles. The full battery assembled by H‐LTO@NCFs anode and LiFePO4 cathode also exhibits outstanding electrochemical performance revealing an encouraging application prospect. This work further demonstrates the effectiveness of self‐doping of metal ions on reinforcing the high‐rate charge/discharge capability of batteries.  相似文献   

10.
The designable structure with 3D structure, ultrathin 2D nanosheets, and heteroatom doping are considered as highly promising routes to improve the electrochemical performance of carbon materials as anodes for lithium‐ion batteries. However, it remains a significant challenge to efficiently integrate 3D interconnected porous frameworks with 2D tunable heteroatom‐doped ultrathin carbon layers to further boost the performance. Herein, a novel nanostructure consisting of a uniform ultrathin N‐doped carbon layer in situ coated on a 3D graphene framework (NC@GF) through solvothermal self‐assembly/polymerization and pyrolysis is reported. The NC@GF with the nanosheets thickness of 4.0 nm and N content of 4.13 at% exhibits an ultrahigh reversible capacity of 2018 mA h g?1 at 0.5 A g?1 and an ultrafast charge–discharge feature with a remarkable capacity of 340 mA h g?1 at an ultrahigh current density of 40 A g?1 and a superlong cycle life with a capacity retention of 93% after 10 000 cycles at 40 A g?1. More importantly, when coupled with LiFePO4 cathode, the fabricated lithium‐ion full cells also exhibit high capacity and excellent rate and cycling performances, highlighting the practicability of this NC@GF.  相似文献   

11.
An ultrahigh pyridinic N‐content‐doped porous carbon monolith is reported, and the content of pyridinic N reaches up to 10.1% in overall material (53.4 ± 0.9% out of 18.9 ± 0.4% N content), being higher than most of previously reported N‐doping carbonaceous materials, which exhibit greatly improved electrochemical performance for potassium storage, especially in term of the high reversible capacity. Remarkably, the pyridinic N‐doped porous carbon monolith (PNCM) electrode exhibits high initial charge capacity of 487 mAh g?1 at a current density of 20 mA g?1, which is one of the highest reversible capacities among all carbonaceous anodes for K‐ion batteries. Moreover, the K‐ion full cell is successfully assembled, demonstrating a high practical energy density of 153.5 Wh kg?1. These results make PNCM promising for practical application in energy storage devices and encourage more investigations on a similar potassium storage system.  相似文献   

12.
Nitrogen‐doped graphene (NG) with wrinkled and bubble‐like texture is fabricated by a thermal treatment. Especially, a novel sonication‐assisted pretreatment with nitric acid is used to further oxidize graphene oxide and its binding with melamine molecules. There are many bubble‐like nanoflakes with a dimension of about 10 nm appeared on the undulated graphene nanosheets. The bubble‐like texture provides more active sites for effective ion transport and reversible capacitive behavior. The specific surface area of NG (5.03 at% N) can reach up to 438.7 m2 g?1, and the NG electrode demonstrates high specific capacitance (481 F g?1 at 1 A g?1, four times higher than reduced graphene oxide electrode (127.5 F g?1)), superior cycle stability (the capacitance retention of 98.9% in 2 m KOH and 99.2% in 1 m H2SO4 after 8000 cycles), and excellent energy density (42.8 Wh kg?1 at power density of 500 W kg?1 in 2 m KOH aqueous electrolyte). The results indicate the potential use of NG as graphene‐based electrode material for energy storage devices.  相似文献   

13.
Preventing the aggregation of nanosized electrode materials is a key point to fully utilize the advantage of the high capacity. In this work, a facile and low‐cost surface solvation treatment is developed to synthesize Fe2VO4 hierarchical porous microparticles, which efficiently prevents the aggregation of the Fe2VO4 primary nanoparticles. The reaction between alcohol molecules and surface hydroxy groups is confirmed by density functional theory calculations and Fourier transform infrared spectroscopy. The electrochemical mechanism of Fe2VO4 as lithium‐ion battery anode is characterized by in situ X‐ray diffraction for the first time. This electrode material is capable of delivering a high reversible discharge capacity of 799 mA h g?1 at 0.5 A g?1 with a high initial coulombic efficiency of 79%, and the capacity retention is 78% after 500 cycles. Moreover, a remarkable reversible discharge capacity of 679 mA h g?1 is achieved at 5 A g?1. Furthermore, when tested as sodium‐ion battery anode, a high reversible capacity of 382 mA h g?1 can be delivered at the current density of 1 A g?1, which still retains at 229 mA h g?1 after 1000 cycles. The superior electrochemical performance makes it a potential anode material for high‐rate and long‐life lithium/sodium‐ion batteries.  相似文献   

14.
The combination of high‐capacity and long‐term cycling stability is an important factor for practical application of anode materials for lithium‐ion batteries. Herein, NixMnyCozO nanowire (x + y + z = 1)/carbon nanotube (CNT) composite microspheres with a 3D interconnected conductive network structure (3DICN‐NCS) are prepared via a spray‐drying method. The 3D interconnected conductive network structure can facilitate the penetration of electrolyte into the microspheres and provide excellent connectivity for rapid Li+ ion/electron transfer in the microspheres, thus greatly reducing the concentration polarization in the electrode. Additionally, the empty spaces among the nanowires in the network accommodate microsphere volume expansion associated with Li+ intercalation during the cycling process, which improves the cycling stability of the electrode. The CNTs distribute uniformly in the microspheres, which act as conductive frameworks to greatly improve the electrical conductivity of the microspheres. As expected, the prepared 3DICN‐NCS demonstrates excellent electrochemical performance, showing a high capacity of 1277 mAh g?1 at 1 A g?1 after 2000 cycles and 790 mAh g?1 at 5 A g?1 after 1000 cycles. This work demonstrates a universal method to construct a 3D interconnected conductive network structure for anode materials  相似文献   

15.
Yolk–shell nanostructures have received great attention for boosting the performance of lithium‐ion batteries because of their obvious advantages in solving the problems associated with large volume change, low conductivity, and short diffusion path for Li+ ion transport. A universal strategy for making hollow transition metal oxide (TMO) nanoparticles (NPs) encapsulated into B, N co‐doped graphitic nanotubes (TMO@BNG (TMO = CoO, Ni2O3, Mn3O4) through combining pyrolysis with an oxidation method is reported herein. The as‐made TMO@BNG exhibits the TMO‐dependent lithium‐ion storage ability, in which CoO@BNG nanotubes exhibit highest lithium‐ion storage capacity of 1554 mA h g?1 at the current density of 96 mA g?1, good rate ability (410 mA h g?1 at 1.75 A g?1), and high stability (almost 96% storage capacity retention after 480 cycles). The present work highlights the importance of introducing hollow TMO NPs with thin wall into BNG with large surface area for boosting LIBs in the terms of storage capacity, rate capability, and cycling stability.  相似文献   

16.
High‐rate performance flexible lithium‐ion batteries are desirable for the realization of wearable electronics. The flexibility of the electrode in the battery is a key requirement for this technology. In the present work, spinel lithium titanate (Li4Ti5O12, LTO) cuboid arrays are grown on flexible carbon fiber cloth (CFC) to fabricate a binder‐free composite electrode (LTO@CFC) for flexible lithium‐ion batteries. Experimental results show that the LTO@CFC electrode exhibits a remarkably high‐rate performance with a capacity of 105.8 mAh g?1 at 50C and an excellent electrochemical stability against cycling (only 2.2% capacity loss after 1000 cycles at 10C). A flexible full cell fabricated with the LTO@CFC as the anode and LiNi0.5Mn1.5O4 coated on Al foil as the cathode displays a reversible capacity of 109.1 mAh g?1 at 10C, an excellent stability against cycling and a great mechanical stability against bending. The observed high‐rate performance of the LTO@CFC electrode is due to its unique corn‐like architecture with LTO cuboid arrays (corn kernels) grown on CFC (corn cob). This work presents a new approach to preparing LTO‐based composite electrodes with an architecture favorable for ion and electron transport for flexible energy storage devices.  相似文献   

17.
Molybdenum disulfide (MoS2) is a promising electrode material for electrochemical energy storage owing to its high theoretical specific capacity and fascinating 2D layered structure. However, its sluggish kinetics for ionic diffusion and charge transfer limits its practical applications. Here, a promising strategy is reported for enhancing the Na+‐ion charge storage kinetics of MoS2 for supercapacitors. In this strategy, electrical conductivity is enhanced and the diffusion barrier of Na+ ion is lowered by a facile phosphorus‐doping treatment. Density functional theory results reveal that the lowest energy barrier of dilute Na‐vacancy diffusion on P‐doped MoS2 (0.11 eV) is considerably lower than that on pure MoS2 (0.19 eV), thereby signifying a prominent rate performance at high Na intercalation stages upon P‐doping. Moreover, the Na‐vacancy diffusion coefficient of the P‐doped MoS2 at room temperatures can be enhanced substantially by approximately two orders of magnitude (10?6–10?4 cm2 s?1) compared with pure MoS2. Finally, the quasi‐solid‐state asymmetrical supercapacitor assembled with P‐doped MoS2 and MnO2, as the positive and negative electrode materials, respectively, exhibits an ultrahigh energy density of 67.4 W h kg?1 at 850 W kg?1 and excellent cycling stability with 93.4% capacitance retention after 5000 cycles at 8 A g?1.  相似文献   

18.
A novel spinel Co2VO4 is studied as the Li‐ion battery anode material and it is sandwiched with a 3D ultralight porous current collector (PCC) and amorphous carbon. Co2VO4 demonstrates the high capacity and excellent cyclability because of the mixed lithium storage mechanisms. The 3D composite structure requires no binders and replaces the conventional current collector (Cu foil) with a 3D ultralight porous metal scaffold, yielding the high electrode‐based capacity. Such a novel composite anode also enables the close adhesion of Co2VO4 to the PCC scaffold. The resulting monolithic electrode has the rapid electron pathway and stable mechanical properties, which lead to the excellent rate capabilities and cycling properties. At a current density of 1 A g?1, the PCC and carbon sandwiched Co2VO4 anode is able to deliver a stable reversible capacity of about 706.8 mAh g?1 after 1000 cycles. Generally, this study not only develops a new Co2VO4 anode with high capacity and good cyclability, but also demonstrates an alternative approach to improve the electrochemical properties of high capacity anode materials by using ultralight porous metallic current collector instead of heavy copper foil.  相似文献   

19.
With the unique‐layered structure, MXenes show potential as electrodes in energy‐storage devices including lithium‐ion (Li+) capacitors and batteries. However, the low Li+‐storage capacity hinders the application of MXenes in place of commercial carbon materials. Here, the vanadium carbide (V2C) MXene with engineered interlayer spacing for desirable storage capacity is demonstrated. The interlayer distance of pristine V2C MXene is controllably tuned to 0.735 nm resulting in improved Li‐ion capacity of 686.7 mA h g?1 at 0.1 A g?1, the best MXene‐based Li+‐storage capacity reported so far. Further, cobalt ions are stably intercalated into the interlayer of V2C MXene to form a new interlayer‐expanded structure via strong V–O–Co bonding. The intercalated V2C MXene electrodes not only exhibit superior capacity up to 1117.3 mA h g?1 at 0.1 A g?1, but also deliver a significantly ultralong cycling stability over 15 000 cycles. These results clearly suggest that MXene materials with an engineered interlayer distance will be a rational route for realizing them as superstable and high‐performance Li+ capacitor electrodes.  相似文献   

20.
Supercapacitors have aroused considerable attention due to their high power capability, which enables charge storage/output in minutes or even seconds. However, to achieve a high energy density in a supercapacitor has been a long‐standing challenge. Here, graphite is reported as a high‐energy alternative to the frequently used activated carbon (AC) cathode for supercapacitor application due to its unique Faradaic pseudocapacitive anion intercalation behavior. The graphite cathode manifests both higher gravimetric and volumetric energy density (498 Wh kg?1 and 431.2 Wh l?1) than an AC cathode (234 Wh kg?1 and 83.5 Wh l?1) with peak power densities of 43.6 kW kg?1 and 37.75 kW l?1. A new type of Li‐ion pseudocapacitor (LIpC) is thus proposed and demonstrated with graphite as cathode and prelithiated graphite or Li4Ti5O12 (LTO) as anode. The resultant graphite–graphite LIpCs deliver high energy densities of 167–233 Wh kg?1 at power densities of 0.22–21.0 kW kg?1 (based on active mass in both electrodes), much higher than 20–146 Wh kg?1 of AC‐derived Li‐ion capacitors and 23–67 Wh kg?1 of state‐of‐the‐art metal oxide pseudocapacitors. Excellent rate capability and cycling stability are further demonstrated for LTO‐graphite LIpCs.  相似文献   

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