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1.
Herein we present a simple method for fabricating core–shell mesostructured CuO@C nanocomposites by utilizing humic acid (HA) as a biomass carbon source. The electrochemical performances of CuO@C nanocomposites were evaluated as an electrode material for supercapacitors and lithium‐ion batteries. CuO@C exhibits an excellent capacitance of 207.2 F g ?1 at a current density of 1 A g ?1 within a potential window of 0–0.46 V in 6 M KOH solution. Significantly, CuO electrode materials achieve remarkable capacitance retentions of approximately 205.8 F g ?1 after 1000 cycles of charge/discharge testing. The CuO@C was further applied as an anode material for lithium‐ion batteries, and a high initial capacity of 1143.7 mA h g ?1 was achieved at a current density of 0.1 C. This work provides a facile and general approach to synthesize carbon‐based materials for application in large‐scale energy‐storage systems. 相似文献
2.
We report a simple approach based on a chemical reduction method to synthesize aqueous inorganic ink comprised of hexagonal MnO 2 nanosheets. The MnO 2 ink exhibits long‐term stability and continuous thin films can be formed on various substrates without using any binder. To obtain a flexible electrode for capacitive energy storage, the MnO 2 ink was printed onto commercially available A4 paper pretreated with multiwalled carbon nanotubes. The electrode exhibited a maximum specific capacitance of 1035 F g ?1 (91.7 mF cm ?2). Paper‐based symmetric and asymmetric capacitors were assembled, which gave a maximum specific energy density of 25.3 Wh kg ?1 and a power density of 81 kW kg ?1. The device could maintain a 98.9 % capacitance retention over 10 000 cycles at 4 A g ?1. The MnO 2 ink could be a versatile candidate for large‐scale production of flexible and printable electronic devices for energy storage and conversion. 相似文献
3.
A facile and sustainable procedure for the synthesis of nitrogen‐doped hierarchical porous carbons with a three‐dimensional interconnected framework (NHPC‐3D) was developed. The strategy, based on a colloidal crystal‐templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self‐polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well‐preserved nitrogen doping after heat treatment. The obtained NHPC‐3D possesses a high surface area of 1056 m 2 g ?1, a large pore volume of 2.56 cm 3 g ?1, and a high nitrogen content of 8.2 wt %. The NHPC‐3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g ?1 at a current density of 2 A g ?1. The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g ?1 in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion‐transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC‐3D as a promising candidate for electrode materials in supercapacitors. 相似文献
4.
Advanced methods, allowing the controllable synthesis of ordered structural nanomaterials with favourable charges transfer and storage, are highly important to achieve ideal supercapacitors with high energy density. Herein, we report a microliter droplet‐based method to synthesize hierarchical‐structured metal–organic framework/graphene/carbon nanotubes hybrids. The confined ultra‐small‐volume reaction, give well‐defined hybrids with a large specific‐surface‐area (1206 m 2 g ?1), abundant ionic‐channels (narrow pore of 0.86 nm), and nitrogen active‐sites (10.63 %), resulting in high pore‐size utilization (97.9 %) and redox‐activity (32.3 %). We also propose a scalable microfluidic‐blow‐spinning method to consecutively generate nanofibre‐based flexible supercapacitor electrodes with striking flexibility and mechanical strength. The supercapacitors display large volumetric energy density (147.5 mWh cm ?3), high specific capacitance (472 F cm ?3) and stably deformable energy‐supply. 相似文献
5.
Thick, uniform, easily processed, highly conductive polymer films are desirable as electrodes for solar cells as well as polymer capacitors. Here, a novel scalable strategy is developed to prepare highly conductive thick poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (HCT‐PEDOT:PSS) films with layered structure that display a conductivity of 1400 S cm ?1 and a low sheet resistance of 0.59 ohm sq ?1. Organic solar cells with laminated HCT‐PEDOT:PSS exhibit a performance comparable to the reference devices with vacuum‐deposited Ag top electrodes. More importantly, the HCT‐PEDOT:PSS film delivers a specific capacitance of 120 F g ?1 at a current density of 0.4 A g ?1. All‐solid‐state flexible symmetric supercapacitors with the HCT‐PEDOT:PSS films display a high volumetric energy density of 6.80 mWh cm ?3 at a power density of 100 mW cm ?3 and 3.15 mWh cm ?3 at a very high power density of 16160 mW cm ?3 that outperforms previous reported solid‐state supercapacitors based on PEDOT materials. 相似文献
6.
Nitrogen‐enriched porous nanocarbon, graphene, and conductive polymers attract increasing attention for application in supercapacitors. However, electrode materials with a large specific surface area (SSA) and a high nitrogen doping concentration, which is needed for excellent supercapacitors, has not been achieved thus far. Herein, we developed a class of tetracyanoquinodimethane‐derived conductive microporous covalent triazine‐based frameworks (TCNQ‐CTFs) with both high nitrogen content (>8 %) and large SSA (>3600 m 2 g ?1). These CTFs exhibited excellent specific capacitances with the highest value exceeding 380 F g ?1, considerable energy density of 42.8 Wh kg ?1, and remarkable cycling stability without any capacitance degradation after 10 000 cycles. This class of CTFs should hold a great potential as high‐performance electrode material for electrochemical energy‐storage systems. 相似文献
7.
Herein, we report a nanoarchitectured nickel molybdate/carbon fibers@pre‐treated Ni foam (NiMoO 4/CF@PNF) electrode for supercapacitors. The synthesis of NiMoO 4/CF@PNF mainly consists of a direct chemical vapor deposition (CVD) growth of dense carbon fibers (CFs) onto pre‐treated Ni foam (PNF) as the substrate, followed by in situ growth of NiMoO 4 nanosheets (NSs) on the CF@PNF substrate by means of a hydrothermal process. The NiMoO 4/CF@PNF electrode exhibits a high areal capacitance (5.14 F cm ?2 at 4 mA cm ?2) and excellent cycling stability (97 % capacitance retention after 2000 cycles at 10 mA cm ?2). Furthermore, we have successfully assembled NiMoO 4 NSs//activated carbon (AC) asymmetric supercapacitors, which can achieve an energy density of 45.6 Wh kg ?1 at 674 W kg ?1, and excellent stability with 93 % capacitance retention after 2000 cycles at 5 mA cm ?2. These superior properties hold great promise for energy‐storage applications. 相似文献
8.
We have synthesized and characterized perovskite‐type SrCo 0.9Nb 0.1O 3−δ (SCN) as a novel anion‐intercalated electrode material for supercapacitors in an aqueous KOH electrolyte, demonstrating a very high volumetric capacitance of about 2034.6 F cm −3 (and gravimetric capacitance of ca. 773.6 F g −1) at a current density of 0.5 A g −1 while maintaining excellent cycling stability with a capacity retention of 95.7 % after 3000 cycles. When coupled with an activated carbon (AC) electrode, the SCN/AC asymmetric supercapacitor delivered a specific energy density as high as 37.6 Wh kg −1 with robust long‐term stability. 相似文献
9.
A conjugated copper(II) catecholate based metal–organic framework (namely Cu‐DBC) was prepared using a D 2‐symmetric redox‐active ligand in a copper bis(dihydroxy) coordination geometry. The π‐d conjugated framework exhibits typical semiconducting behavior with a high electrical conductivity of ca. 1.0 S m ?1 at room temperature. Benefiting from the good electrical conductivity and the excellent redox reversibility of both ligand and copper centers, Cu‐DBC electrode features superior capacitor performances with gravimetric capacitance up to 479 F g ?1 at a discharge rate of 0.2 A g ?1. Moreover, the symmetric solid‐state supercapacitor of Cu‐DBC exhibits high areal (879 mF cm ?2) and volumetric (22 F cm ?3) capacitances, as well as good rate capability. These metrics are superior to most reported MOF‐based supercapacitors, demonstrating promising applications in energy‐storage devices. 相似文献
10.
High‐performance electrical double‐layer capacitors (EDLCs) require carbon electrode materials with high specific surface area, short ion‐diffusion pathways, and outstanding electrical conductivity. Herein, a general approach combing the molten‐salt method and chemical activation to prepare N‐doped carbon nanosheets with high surface area (654 m 2 g ?1) and adjustable porous structure is presented. Owing to their structural features, the N‐doped carbon nanosheets exhibited superior capacitive performance, demonstrated by a maximum capacitance of 243 F g ?1 (area‐normalized capacitance up to 37 μF cm ?2) at a current density of 0.5 A g ?1 in aqueous electrolyte, high rate capability (179 F g ?1 at 20 A g ?1), and excellent cycle stability. This method provides a new route to prepare porous and heteroatom‐doped carbon nanosheets for high‐performance EDLCs, which could also be extended to other polymer precursors and even waste biomass. 相似文献
11.
Owing to their graphene‐like structure and available oxidation valence states, transition metal sulfides are promising candidates for supercapacitors. Herein, we report the application of MoS 3 as a new negative electrode for supercapacitors. MoS 3 was fabricated by the facile thermal decomposition of a (NH 4) 2MoS 4 precursor. For comparison, samples of MoS 3&MoS 2 and MoS 2 were also synthesized by using the same method. Moreover, this is the first report of the application of MoS 3 as a negative electrode for supercapacitors. MoS 3 displayed a high specific capacitance of 455.6 F g ?1 at a current density of 0.5 A g ?1. The capacitance retention of the MoS 3 electrode was 92 % after 1500 cycles, and even 71 % after 5000 cycles. In addition, an asymmetric supercapacitor assembly of MoS 3 as the negative electrode demonstrated a high energy density at a high potential of 2.0 V in aqueous electrolyte. These notable results show that MoS 3 has significant potential in energy‐storage devices. 相似文献
12.
We report a supramolecular strategy to prepare conductive hydrogels with outstanding mechanical and electrochemical properties, which are utilized for flexible solid‐state supercapacitors (SCs) with high performance. The supramolecular assembly of polyaniline and polyvinyl alcohol through dynamic boronate bond yields the polyaniline–polyvinyl alcohol hydrogel (PPH), which shows remarkable tensile strength (5.3 MPa) and electrochemical capacitance (928 F g ?1). The flexible solid‐state supercapacitor based on PPH provides a large capacitance (306 mF cm ?2 and 153 F g ?1) and a high energy density of 13.6 Wh kg ?1, superior to other flexible supercapacitors. The robustness of the PPH‐based supercapacitor is demonstrated by the 100 % capacitance retention after 1000 mechanical folding cycles, and the 90 % capacitance retention after 1000 galvanostatic charge–discharge cycles. The high activity and robustness enable the PPH‐based supercapacitor as a promising power device for flexible electronics. 相似文献
13.
Vanadium pentoxide (V2O5) based electrodes for energy storage devices have captured sizeable attention in the past decade owing to their attractive physiochemical features. In the present work, flaky structured V2O5 was prepared using a single step hydrothermal route. The results from analytical investigations hold up well with the formation scheme proposed. The flaky morphology of V2O5 facilitates additional pathways for electron transport and effective ion access. When employed as a supercapacitor electrode in a neutral electrolyte, this flaky V2O5 electrode demonstrates a specific capacitance of 472 F g?1. Besides, it retains maximum capacitance at higher current density confirming its good rate performance. An asymmetric type supercapacitor using flaky V2O5 as positive electrode and activated carbon as negative electrode exhibits specific capacitance of 69 F g?1. This device shows energy density of 10 W h kg?1 within the operational window of 1 V. 相似文献
14.
A hierarchical hollow hybrid composite, namely, MnO 2 nanosheets grown on nitrogen‐doped hollow carbon shells (NHCSs@MnO 2), was synthesized by a facile in situ growth process followed by calcination. The composite has a high surface area (251 m 2g ?1) and mesopores (4.5 nm in diameter), which can efficiently facilitate transport during electrochemical cycling. Owing to the synergistic effect of NHCSs and MnO 2, the composite shows a high specific capacitance of 306 F g ?1, good rate capability, and an excellent cycling stability of 95.2 % after 5000 cycles at a high current density of 8 A g ?1. More importantly, an asymmetric supercapacitor (ASC) assembled by using NHCSs@MnO 2 and activated carbon as the positive and negative electrodes exhibits high specific capacitance (105.5 F g ?1 at 0.5 A g ?1 and 78.5 F g ?1 at 10 A g ?1) with excellent rate capability, achieves a maximum energy density of 43.9 Wh kg ?1 at a power density of 408 W kg ?1, and has high stability, whereby the ASC retains 81.4 % of its initial capacitance at a current density of 5 A g ?1 after 4000 cycles. Therefore, the NHCSs@MnO 2 electrode material is a promising candidate for future energy‐storage systems. 相似文献
15.
Porous carbons (PC) were prepared from a waste biomass named chestnut shell via a two‐step method involving carbonization and KOH activation. The morphology, pore structure and surface chemical properties were investigated by scanning electron microscopy (SEM), N 2 sorption, Raman spectroscopy, X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). The carbons have been evaluated as the electrode materials for supercapacitors by a two‐electrode system in 6 mol/L KOH electrolyte. Benefiting from the porous texture, high surface area and high oxygen content, the PCs derived from chestnut shell have exhibited high specific capacitance of 198.2 (PC‐1), 217.2 (PC‐2) and 238.2 F·g ?1 (PC‐3) at a current density of 0.1 A·g ?1, good rate capability of 55.7%, 56.6% and 54.9% in a range of 0.1–20 A·g ?1 and high energy density of 5.6, 6.1 and 6.7 Wh·kg ?1, respectively. This is believed to be due to electric double layer capacitance induced by the abundant micropores and extra pseudo‐capacitance generated by oxygen‐containing groups. At a power density of 9000 Wh·kg ?1, the energy density is 3.1, 3.5 and 3.7 Wh·kg ?1 for PC‐1, PC‐2 and PC‐3, respectively, demonstrating the potential of the carbons derived from chestnut shells in energy storage devices. 相似文献
16.
A conceptually new all‐solid‐state asymmetric supercapacitor based on atomically thin sheets is presented which offers the opportunity to optimize supercapacitor properties on an atomic level. As a prototype, β‐Co(OH) 2 single layers with five‐atoms layer thickness were synthesized through an oriented‐attachment strategy. The increased density‐of‐states and 100 % exposed hydrogen atoms endow the β‐Co(OH) 2 single‐layers‐based electrode with a large capacitance of 2028 F g ?1. The corresponding all‐solid‐state asymmetric supercapacitor achieves a high cell voltage of 1.8 V and an exceptional energy density of 98.9 Wh kg ?1 at an ultrahigh power density of 17 981 W kg ?1. Also, this integrated nanodevice exhibits excellent cyclability with 93.2 % capacitance retention after 10 000 cycles, holding great promise for constructing high‐energy storage nanodevices. 相似文献
17.
Herein, we describe a simple two‐step approach to prepare nickel phosphide with different phases, such as Ni 2P and Ni 5P 4, to explain the influence of material microstructure and electrical conductivity on electrochemical performance. In this approach, we first prepared a Ni–P precursor through a ball milling process, then controlled the synthesis of either Ni 2P or Ni 5P 4 by the annealing method. The as‐prepared Ni 2P and Ni 5P 4 are investigated as supercapacitor electrode materials for potential energy storage applications. The Ni 2P exhibits a high specific capacitance of 843.25 F g ?1, whereas the specific capacitance of Ni 5P 4 is 801.5 F g ?1. Ni 2P possesses better cycle stability and rate capability than Ni 5P 4. In addition, the Fe 2O 3//Ni 2P supercapacitor displays a high energy density of 35.5 Wh kg ?1 at a power density of 400 W kg ?1 and long cycle stability with a specific capacitance retention rate of 96 % after 1000 cycles, whereas the Fe 2O 3//Ni 5P 4 supercapacitor exhibits a high energy density of 29.8 Wh kg ?1 at a power density of 400 W kg ?1 and a specific capacitance retention rate of 86 % after 1000 cycles. 相似文献
18.
For the first time, hierarchically porous carbon materials with a sandwich‐like structure are synthesized through a facile and efficient tri‐template approach. The hierarchically porous microstructures consist of abundant macropores and numerous micropores embedded into the crosslinked mesoporous walls. As a result, the obtained carbon material with a unique sandwich‐like structure has a relatively high specific surface (1235 m 2 g ?1), large pore volume (1.30 cm 3 g ?1), and appropriate pore size distribution. These merits lead to a comparably high specific capacitance of 274.8 F g ?1 at 0.2 A g ?1 and satisfying rate performance (87.7 % retention from 1 to 20 A g ?1). More importantly, the symmetric supercapacitor with two identical as‐prepared carbon samples shows a superior energy density of 18.47 Wh kg ?1 at a power density of 179.9 W kg ?1. The asymmetric supercapacitor based on as‐obtained carbon sample and its composite with manganese dioxide (MnO 2) can reach up to an energy density of 25.93 Wh kg ?1 at a power density of 199.9 W kg ?1. Therefore, these unique carbon material open a promising prospect for future development and utilization in the field of energy storage. 相似文献
19.
Multifunctional glass windows that combine energy storage and electrochromism have been obtained by facile thermal evaporation and electrodeposition methods. For example, WO 3 films that had been deposited on fluorine‐doped tin oxide (FTO) glass exhibited a high specific capacitance of 639.8 F g ?1. Their color changed from transparent to deep blue with an abrupt decrease in optical transmittance from 91.3 % to 15.1 % at a wavelength of 633 nm when a voltage of ?0.6 V (vs. Ag/AgCl) was applied, demonstrating its excellent energy‐storage and electrochromism properties. As a second example, a polyaniline‐based pseudocapacitive glass was also developed, and its color can change from green to blue. A large‐scale pseudocapacitive WO 3‐based glass window (15×15 cm 2) was fabricated as a prototype. Such smart pseudocapacitive glass windows show great potential in functioning as electrochromic windows and concurrently powering electronic devices, such as mobile phones or laptops. 相似文献
20.
Phosphorus‐doped (P‐doped) graphene with the P doping level of 1.30 at % was synthesized by annealing the mixture of graphene and phosphoric acid. The presence of P was confirmed by elemental mapping and X‐ray photoelectron spectroscopy, while the morphology of P‐doped graphene was revealed by using scanning electron microscopy and transmission electron microscopy. To investigate the effect of P doping, the electrochemical properties of P‐doped graphene were tested as a supercapacitor electrode in an aqueous electrolyte of 1 M H 2SO 4. The results showed that doping of P in graphene exhibited significant improvement in terms of specific capacitance and cycling stability, compared with undoped graphene electrode. More interestingly, the P‐doped graphene electrode can survive at a wide voltage window of 1.7 V with only 3 % performance degradation after 5000 cycles at a current density of 5 A g ?1, providing a high energy density of 11.64 Wh kg ?1 and a high power density of 831 W kg ?1. 相似文献
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