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1.
ChemSusChem ; : e202401365, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39289157

RESUMEN

Lithium-ion capacitors (LICs) have attracted considerable interest because of their excellent power and energy densities. However, the development of LICs is limited by the low capacity of the cathode and the kinetics mismatch between the cathode and anode. In this work, mesoporous carbon materials (MCs) with uniform pore sizes were prepared using magnesium citrate as the raw material through a self-templating method. During the carbonization process, MgO nanoparticles generated from magnesium citrate act as a template, resulting in a more orderly pore structure. The resultant MCs demonstrate a high specific surface area of 1673 m2 g-1 and an abundance of small mesopores, which significantly accelerated ion migration within the electrolyte and expedited the formation of electric double layers. Benefiting from these advantages, the MCs cathode demonstrates a high reversible specific capacity, excellent cycling stability, and rate performance. The assembled MCs-based LIC provides a high energy density of 152.2 Wh kg-1 and a high power density of 14.3 kW kg-1. After 5000 cycles, a capacity retention rate of 80% at the current density of 1 A g-1 is obtained. These results highlight the excellent potential of MCs as a cathode material for LICs.

2.
Small ; : e2403078, 2024 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-39221641

RESUMEN

Ti3C2Tx (MXene) is widely acknowledged as an excellent substrate for constructing heterogeneous structures with transition metal chalcogenides (TMCs) for boosting the electrochemical performance of lithium-ion storage. However, conventional synthesis strategies inevitably lead to poor electrochemical charge transfer due to Ti3C2Tx-derived TiO2 at the heterogeneous interface between Ti3C2Tx and TMCs. Here, an innovative in situ selenization strategy is proposed to replace the originally generated TiO2 on Ti3C2Tx with metallic TiSe2 interphase, clearing the bottleneck of slow charge transfer barrier caused by MXene oxidation. The construction of bimetallic selenide formed by CoSe2 and TiSe2 generates intrinsic electric fields to guide the fast ion diffusion kinetics in a heterogeneous interface. Additionally, the CoSe2/TiSe2/Ti3C2Tx heterogeneous structure with enhanced structural stability and improved rate performance is confirmed by both experiments and theoretical calculations. The engineered heterogeneous structure exhibits an ultra-high pseudocapacitance contribution (73.1% at 0.1 mV s-1), rendering it well-suited to offset the kinetics differences between double-layer materials. The assembled lithium-ion capacitor based on CoSe2/TiSe2/Ti3C2Tx possesses a high energy density and an ultralong life span (89.5% after 10 000 times at 2 A g-1). This devised strategy provides a feasible solution for utilizing the performance advantages of MXene substrates in lithium storage with ultrafast charge transfer kinetics.

3.
Materials (Basel) ; 17(13)2024 Jun 21.
Artículo en Inglés | MEDLINE | ID: mdl-38998143

RESUMEN

Iron-chalcogenide superconductors continue to captivate researchers due to their diverse crystalline structures and intriguing superconducting properties, positioning them as both a valuable platform for theoretical investigations and promising candidates for practical applications. This review begins with a comprehensive overview of the fabrication techniques employed for various iron-chalcogenide superconductors, accompanied by a summary of their phase diagrams. Subsequently, it delves into the upper critical field, anisotropy, and critical current density. Furthermore, it discusses the successful fabrication of meters-long coated conductors and explores their applications in superconducting radio-frequency cavities and coils. Finally, several prospective avenues for future research are proposed.

4.
Nanotechnology ; 34(43)2023 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-37467737

RESUMEN

MXene materials have become a competitive candidate for electrochemical energy storage due to their unique two-dimensional layered structure, high density, metal-like conductivity, fast ion intercalation, tunable surface terminal groups, and good mechanical flexibilities, showing unique application advantages in the field of supercapacitors. With widely research of MXene in energy storage applications, plenty of studies in synthesis strategies of MXene, including etching, intercalation and exfoliation processes, and its charge storage mechanism in supercapacitors have been conducted. However, the restacking of two-dimensional MXene nanosheets severely affects their electrochemical performance. To prevent the stacking of MXene, MXene-based nanocomposite electrode materials have been developed with remarkable electrochemical performance by incorporating conventional active capacitive materials, including metal oxides/sulfides and conductive polymers, with MXene. This review summarizes the etching strategies of MXenes and selection of intercalants, also discusses the charge storage mechanism of MXenes in aqueous and nonaqueous electrolytes. It mainly expounds the preparation strategies and applications of MXene-based nanocomposites in supercapacitors, including MXene/metal oxide, MXene/metal sulfide, MXene/conducting polymer, and MXene/carbon-based composites. Additionally, the advantages of combining MXene with other active materials in supercapacitor applications, which support its promising prospects, are discussed. Finally, the critical challenges faced by MXene-based nanocomposites in long-term research are mentioned.

5.
ACS Appl Mater Interfaces ; 15(21): 26215-26224, 2023 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-37212392

RESUMEN

Increasing the thickness of a superconducting layer and simultaneously reducing the thickness effect in iron-based superconducting coated conductors are particularly essential for improving the critical current Ic. Here, for the first time, we have deposited high-performance FeSe0.5Te0.5 (FST) superconducting films up to 2 µm on LaMnO3-buffered metal tapes by pulsed laser deposition. An interface engineering strategy, alternating growth of a 10 nm-thick nonsuperconducting FST seed layer and a 400 nm-thick FST superconducting layer, was employed to guarantee the crystalline quality of the films with thicknesses of the order of micrometers, resulting in a highly biaxial texture with grain boundary misorientation angle less than the critical value θc ∼ 9°. Moreover, the thickness effect, that the critical current density (Jc) shows a clear dependence on thickness as in cuprates, is reduced by the interface engineering. Also, the maximum Jc was found for a 400 nm-thick film with 1.3 MA/cm2 in self-field at 4.2 K and 0.71 MA/cm2 (H∥ab) and 0.50 MA/cm2 (H∥c) at 9 T. Anisotropic Ginzburg-Landau scaling indicates that the major pinning centers vary from correlated to uncorrelated as the film thickness increases, while the thickness effect is most likely related to the weakening of flux pinning by the fluctuation of charge-carrier mean free path (δl) and strengthening of flux pinning caused by the variation of superconducting transition temperature (δTc) due to off-stoichiometry with thickness.

6.
Materials (Basel) ; 16(5)2023 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-36902902

RESUMEN

Fabrication of high-performance superconducting wires and tapes is essential for large-scale applications of superconducting materials. The powder-in-tube (PIT) method involves a series of cold processes and heat treatments and has been widely used for fabricating BSCCO, MgB2, and iron-based superconducting wires. The densification of the superconducting core is limited by traditional heat treatment under atmospheric pressure. The low density of the superconducting core and a large number of pores and cracks are the main factors limiting the current-carrying performance of PIT wires. Therefore, to improve the transport critical current density of the wires, it is essential to densify the superconducting core and eliminate pores and cracks to enhance grain connectivity. Hot isostatic pressing (HIP) sintering was employed to improve the mass density of superconducting wires and tapes. In this paper, we review the development and application of the HIP process in the manufacturing of BSCCO, MgB2, and iron-based superconducting wires and tapes. The development of HIP parameters and the performance of different wires and tapes are reviewed. Finally, we discuss the advantages and prospects of the HIP process for the fabrication of superconducting wires and tapes.

7.
Front Plant Sci ; 13: 1039671, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36311108

RESUMEN

It's been long known that the application of organic fertilizer (OF) and bio-organic fertilizer (BF) which containing beneficial microorganisms to pear trees can both significantly improve fruit quality and yield. In order to reveal the mechanism of BF and OF regulating fruit growth and quality in pear, the effects of BF and OF on the photosynthetic characteristics and the accumulation of major sugars and organic acids of the pear fruit were quantified compared with chemical fertilizer (CF). Additionally, the molecular mechanisms regulating pear fruit development and quality were studied through transcriptome analysis. The three treatments were conducted based on the same amounts of nitrogen supply. The results showed that compared with CF, BF and OF treatments increased the fruit yield, and also significantly improved the photosynthesis efficiency in pear. BF and OF both significantly increased the sucrose content but significantly decreased the fructose and glucose content within the pear fruit. The amount of malic acid was significantly higher in OF treatment. Compared with CF and OF, BF significantly increased the sugar-acid ratio and thus improved the fruit quality. Transcriptome analysis and weighted correlation network analysis (WGCNA) revealed that the sugar metabolism of fruits applied with the BF was enhanced compared with those applied with CF or OF. More specifically, the expression of SDH (Sorbitol dehydrogenase) was higher in BF, which converts sorbitol into fructose. For both of the OF and BF, the transcript abundance of sugar transporter genes was significantly increased, such as SOT (Sorbitol transporter), SUT14 (Sugar transport 14), UDP-GLUT4 (UDP-glucose transporter 4), UDP-SUT (UDP-sugar transporter), SUC4 (Sucrose transport 4), SUT7 (Sugar transporter 7), SWEET10 and SWEET15 (Bidirectional sugar transporter), which ensures sugar transportation. The genes involved in organic acid metabolism showed decreased transcripts abundance in both BF and OF treatments, such as VAP (Vesicle-associated protein) and cyACO (Cytosolic aconitase), which reduce the conversion from succinate to citric acid, and decrease the conversion from citric acid to malic acid in the TCA cycle (Tricarboxylic Acid cycle) through Pept6 (Oligopeptide transporter). In conclusion, the application of BF and OF improved fruit quality by regulating the expression of sugar and organic acid metabolism-related genes and thus altering the sugar acid metabolism. Both BF and OF promote sucrose accumulation and citric acid degradation in fruits, which may be an important reason for improving pear fruit quality. The possible mechanism of bio-organic fertilizer to improve fruit quality was discussed.

8.
AMB Express ; 11(1): 164, 2021 Dec 08.
Artículo en Inglés | MEDLINE | ID: mdl-34878599

RESUMEN

Severe early defoliation has become an important factor restricting the development of the pear industry in southern China. However, the assembly patterns of microbial communities and their functional activities in response to the application of bioorganic fertilizer (BIO) or humic acid (HA) in southern China's pear orchards remain poorly understood, particularly the impact on the early defoliation of the trees. We conducted a 3-year field experiment (2017-2019) in an 18-year-old 'Cuiguan' pear orchard. Four fertilization schemes were tested: local custom fertilization as control (CK), CK plus HA (CK-HA), BIO, and BIO plus HA (BIO-HA). Results showed that BIO and BIO-HA application decreased the early defoliation rate by 50-60%, and increased pear yield by 40% compared with the CK and CK-HA treatments. The BIO and BIO-HA application significantly improved soil pH, available nutrient content, total enzyme activity and ecosystem multifunctionality, and also changed the structure of soil bacterial and fungal communities. The genus Acidothermus was positively correlated with the early defoliation rate, while the genus Rhodanobacter was negatively correlated. Additionally, random forest models revealed that the early defoliation rate could be best explained by soil pH, ammonium content, available phosphorus, and total enzyme activity. In conclusion, application of BIO or BIO mixed with HA could have assembled distinct microbial communities and increased total enzyme activity, leading to significant improvement of soil physicochemical traits. The increased availability of soil nutrient thus changed leaf nutrient concentrations and alleviated the early defoliation rate of pear trees in acid red soil in southern China.

9.
J Phys Chem Lett ; 12(43): 10603-10609, 2021 Nov 04.
Artículo en Inglés | MEDLINE | ID: mdl-34697941

RESUMEN

High-quality solid electrolyte is the key to developing high-performance all-solid-state lithium-metal batteries (ASSLMBs). Herein, we report a thin composite polymer electrolyte (CPE) based on nanosized Li6.4La3Zr1.4Ta0.6O12 (N-LLZTO) and the PVDF-HFP matrix through a simple film-casting method. N-LLZTO induces partial dehydrofluorination of the poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) matrix that activates the coordination of Li+ with PVDF-HFP and LLZTO due to Lewis acid-base interactions, which facilitates dissociation of lithium salt to increase the Li+ carrier density. As a result, the as-fabricated composite polymer electrolyte with a 20 wt % N-LLZTO (CPE-20) membrane possesses high ionic conductivity (1.7 × 10-4 S cm-1), a high lithium-ion transference number (0.57), a wide electrochemical window (∼4.8 V), and good thermal stability. Moreover, the CPE-20 membrane displays excellent electrochemical stability to suppress the lithium dendrite and serves more than 2000 h. The solid-state Li|CPE-20|LiFePO4 pouch cells exhibit excellent cycling and rate performance, as well as high energy density. This study presents an effective strategy to design promising solid-state electrolyte for next-generation ASSLMBs.

10.
iScience ; 24(8): 102922, 2021 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-34409275

RESUMEN

High-quality Co-doped BaFe2As2 thin films with thickness up to 2 µm were realized on flexible metal tapes with LaMnO3 as buffer layers fabricated by an ion beam-assisted deposition technique. Structural analysis indicates that increasing thickness does not compromise the film crystallinity, except for a small amount of impurities. Two types of thickness dependence of critical current density (J c) were found: one is almost thickness independent in the range of 0.6-1.5 µm and the other is highly thickness dependent. In addition, the maximum value for crucial current I c at 9 T and 4.2 K is about 55 A/12 mm-W for the 1.5-µm-thick film. Anisotropic Ginzburg-Landau scaling demonstrates that dominant pinning centers develop from correlated to uncorrelated with increasing film thickness. The further theoretical analysis shows that with film thickness increasing the pinning mechanism evolves progressively from a δl pinning to the δT c pinning mechanism.

11.
iScience ; 24(6): 102541, 2021 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-34136765

RESUMEN

Superconducting materials hold great potential to bring radical changes for electric power and high-field magnet technology, enabling high-efficiency electric power generation, high-capacity loss-less electric power transmission, small lightweight electrical equipment, high-speed maglev transportation, ultra-strong magnetic field generation for high-resolution magnetic resonance imaging (MRI) systems, nuclear magnetic resonance (NMR) systems, future advanced high energy particle accelerators, nuclear fusion reactors, and so on. The performance, economy, and operating parameters (temperatures and magnetic fields) of these applications strongly depend on the electromagnetic and mechanical properties, as well as the manufacturing and material cost of superconductors. This perspective examines the basic properties relevant to practical applications and key issues of wire fabrication for practical superconducting materials, and describes their challenges and current state in practical applications. Finally, future perspectives for their opportunities and development in the applications of superconducting power and magnetic technologies are considered.

12.
Sci Bull (Beijing) ; 66(9): 914-924, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-36654240

RESUMEN

Two-dimensional (2D) material MXenes have been intensively concerned in energy-storage field due to these unique properties of metallic-like conductivity, good hydrophilicity and high volumetric capacity. However, the self-restocking of ultra-thin 2D materials seriously hinders these performances, which significantly inhibits the full exploitation of MXenes in the field of energy storage. To solve this issue, a strategy to prepare delaminated Ti3C2Tx (MXene) nanoflakes/reduced graphene oxide (rGO) composites is proposed using the electrostatic self-assembly between positively charged Ti3C2Tx with tetrabutylammonium ion (TBA+) modification and negatively charged graphene. The nanoflakes of Ti3C2Tx/rGO are well dispersed and arranged in a face-to-face structure to effectively alleviate the self-restacking and provide more electroactive sites for accessible of electrolyte ions. The prepared delaminated Ti3C2Tx/rGO anode shows a high reversible capacity up to 1394 mAh g-1 at a current density of 50 mA g-1. Moreover, a lithium-ion capacitor (LIC) was assembled with delaminated Ti3C2Tx/rGO anode and activated carbon (AC) cathode which can exhibit a specific capacity of 70.7 F g-1 at a current density of 0.1 A g-1 and deliver an ultrahigh energy density of 114 Wh kg-1 at a relatively high power density of 3125 W kg-1. These good electrochemical performances demonstrate the potential of delaminated Ti3C2Tx/rGO as an anode material for lithium-ion capacitors.

13.
Adv Mater ; 32(45): e2005531, 2020 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33002239

RESUMEN

Smart and wearable electronics have aroused substantial demand for flexible portable power sources, but it remains a large challenge to realize scalable production of wearable batteries/supercapacitors with high electrochemical performance and remarkable flexibility simultaneously. Here, a scalable approach is developed to prepare wearable solid-state lithium-ion capacitors (LICs) with superior performance enabled by synergetic engineering from materials to device architecture. Nitrogen-doped hierarchical carbon (HC) composed of 1D carbon nanofibers welded with 2D carbon nanosheets is synthesized via a unique self-propagating high-temperature synthesis (SHS) technique, which exhibits superior electrochemical performance. Subsequently, inspired by origami, here, wave-shaped LIC punch-cells based on the above materials are designed by employing a compatible and scalable post-imprint technology. Finite elemental analysis (FEA) confirms that the bending stress of the punch-cell can be offset effectively, benefiting from the wave architecture. The wearable solid-state LIC punch-cell exhibits large energy density, long cyclic stability, and superior flexibility. This study demonstrates great promise for scalable fabrication of wearable energy-storage systems.

14.
ACS Omega ; 5(1): 75-82, 2020 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-31956753

RESUMEN

Recently, two-dimensional MXenes and MXene-based nanocomposites have become the most important electrode materials because of their unique physical and chemical characteristics. As the electrode of a lithium-ion capacitor, MXenes have exhibited metallic conductivity and plastic layer structure that provide more chemically active interfaces and shortened ion-diffusion lengths, and thus the unbalanced ion kinetics between the anode and cathode can be effectively alleviated. In order to further improve the electrochemical performance of MXenes, the composition, morphology and texture, surface chemistry, and structural configuration of MXenes are extensively investigated. In this mini-review, some recent research and progress of MXenes and MXene-based nanocomposites in lithium-ion capacitors are summarized, which focus on their nanostructure designs and chemical preparation methods, such as prepillaring MXenes, delaminated MXenes, and MXene-based hybrids. Finally, some future perspectives and critical challenges of MXene-based material for lithium-ion capacitor application are also presented and briefly discussed.

15.
Nanoscale Adv ; 2(1): 296-303, 2020 Jan 22.
Artículo en Inglés | MEDLINE | ID: mdl-36133974

RESUMEN

The increasing demand for large-scale manufacture of wearable electronics requires applicable energy storage devices with high-performance and safety. In this paper, we reported a solid-state Zn battery based on a free-standing organic cathode and metal Zn anode with an orderly aligned nano-architecture. The cathode is fabricated by depositing organic nanowire arrays on a carbon nanotube film via an in situ polymerization process, and the anode was prepared by electrodepositing Zn nanosheet arrays on carbon cloth. To avoid electrolyte leakage risks, a pseudo-solid-state PAAM-ZnSO4 gel electrolyte is employed, which is synthesized via a chemical cross-linking and film casting approach. The orderly aligned nanostructure of PANI nanowire arrays and zinc nanosheet arrays exhibits superior electrochemical performance, while the free-standing electrode configuration simplifies the battery fabrication process and offers excellent flexibility. The resulting solid-state Zn battery delivered a high capacity of 144 mA h g-1 at a current density of 0.2 A g-1, a 91.1% capacity retention after 150 cycles at a current density of 0.5 A g-1, and excellent flexibility under different bending states. This high-performance solid-state Zn battery provides a promising alternative energy storage device for next generation wearable electronics.

16.
ACS Synth Biol ; 8(7): 1620-1630, 2019 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-31250633

RESUMEN

Vitamin K is essential for blood coagulation and plays important roles in bone and cardiovascular health. Menaquinone-7 (MK-7) is one form of vitamin K that is especially useful due to its long half-life in the circulation. MK-7 is difficult to make via organic synthesis, and is thus commonly produced by fermentation. This study aimed to genetically modify Bacillus subtilis cultures to increase their MK-7 yield and reduce production costs. We constructed 12 different strains of B. subtilis 168 by overexpressing different combinations of the rate-limiting enzymes Dxs, Dxr, Idi, and MenA. We observed an 11-fold enhancement of production in the best-performing strain, resulting in 50 mg/L MK-7. Metabolite analysis revealed new bottlenecks in the pathway at IspG and IspH, which suggest avenues for further optimization. This work highlights the usefulness of Bacillus subtilis for industrial production of high value compounds.


Asunto(s)
Bacillus subtilis/metabolismo , Proteínas Bacterianas/metabolismo , Receptor EphB6/metabolismo , Transducción de Señal/fisiología , Vitamina K 2/análogos & derivados , Medios de Cultivo/metabolismo , Fermentación/fisiología , Ingeniería Metabólica/métodos , Vitamina K 2/metabolismo
17.
Nanoscale ; 10(27): 13083-13091, 2018 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-29961783

RESUMEN

In this paper, we developed a novel Zn-ion hybrid cell based on a graphene-conducting polymer composite hydrogel (capacitor-type) cathode and a zinc metal (battery-type) anode. The pseudocapacitive-type cathode materials can effectively boost the capacity of Zn-ion hybrid cell compared to that of electrical double layer cathode materials. In particular, the composite hydrogel with rational designed three-dimensional (3D) nano-architecture combining 3D porous nanostructure with hydrogel, can significantly enlarge the active interfaces between the electrode and electrolyte. According to our experiments, the 3D graphene@PANI composite hydrogel electrode exhibits a large capacity of 154 mA h g-1, a superior rate capability and excellent capacity retention of 80.5% after 6000 charge-discharge cycles in a Zn-ion hybrid cell. The outstanding electrochemical properties demonstrate that the 3D nanostructure composite hydrogel materials can effectively promote the material utilization, transport of charges, and reduce the degradation of conducting polymers, leading to a highly efficient, fast and stable electrochemical process. Based on our results, Zn-ion hybrid cells based on a composite hydrogel electrode could be an extremely promising candidate for next generation electrochemical energy storage devices.

18.
ACS Appl Mater Interfaces ; 10(29): 24573-24582, 2018 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-29956913

RESUMEN

Nowadays, linear-shaped batteries have received increasing attentions because the unique one-dimensional architecture offers an omni-directional flexibility. We developed a cable-type flexible rechargeable Zn microbattery based on a microscale MnO2@carbon nanotube fiberlike composite cathode and Zn wire anode. The Zn-MnO2 cable microbattery exhibits a large specific capacity, good rate performance, and cyclic stability. The capacity of Zn-MnO2 cable batteries are 322 and 290 mAh/g based on MnO2 with aqueous and gel polymer electrolyte, corresponding to the specific energy of 437 and 360 Wh/kg, respectively. Besides, the Zn-MnO2 cable battery shows excellent flexibility, which can be folded into arbitrary shapes without sacrificing electrochemical performance. Furthermore, we studied electrochemical properties of Zn-MnO2 cable microbatteries with different Zn salt electrolytes, such as Zn salt with small anions (ZnSO4 or ZnCl2, etc.) and Zn salt with bulky anions (Zn(CF3SO3)2, etc.). With the merits of impressive electrochemical performance and flexibility, this first flexible rechargeable Zn-MnO2 cable-like battery presents a new approach to develop high-performance power sources for portable and wearable electronics.

19.
Nanoscale ; 10(13): 5906-5913, 2018 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-29537043

RESUMEN

Two-dimensional (2D) MXenes have a very good application prospect in the field of electrochemical energy storage due to their metallic conductivity, high volumetric capacity, mechanical and thermal stability. Herein, we report the preparation of titanium carbide (Ti3C2Tx)/carbon nanotube (CNT) flexible self-supporting composite films by vacuum filtration. The CNTs can effectively prevent Ti3C2Tx from stacking and improve the electrochemical performance. The as-fabricated Ti3C2Tx/CNT film shows a high reversible capacity of 489 mA h g-1 at a current density of 50 mA g-1 together with good cycling performance. The full-cell lithium-ion capacitor (LIC) is assembled using the Ti3C2Tx/CNT film as the anode and activated carbon as the cathode. The LIC exhibits a high energy density of 67 Wh kg-1 (based on the total weight of the anode and the cathode), and a good capacity retention of 81.3% after 5000 cycles. These results suggest that Ti3C2Tx-CNT films are promising as anode materials for lithium ion capacitors.

20.
ACS Appl Mater Interfaces ; 9(20): 17136-17144, 2017 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-28474525

RESUMEN

Lithium-ion capacitors (LICs) are considered as promising energy storage devices to realize excellent electrochemical performance, with high energy-power output. In this work, we employed a simple method to synthesize a composite electrode material consisting of Fe3O4 nanocrystallites mechanically anchored among the layers of three-dimensional arrays of graphene (Fe3O4-G), which exhibits several advantages compared with other traditional electrode materials, such as high Li storage capacity (820 mAh g-1 at 0.1 A g-1), high electrical conductivity, and improved electrochemical stability. Furthermore, on the basis of the appropriated charge balance between cathode and anode, we successfully fabricated Fe3O4-G//activated carbon (AC) soft-packaging LICs with a high energy density of 120.0 Wh kg-1, an outstanding power density of 45.4 kW kg-1 (achieved at 60.5 Wh kg-1), and an excellent capacity retention of up to 94.1% after 1000 cycles and 81.4% after 10 000 cycles. The energy density of the Fe3O4-G//AC hybrid device is comparable with Ni-metal hydride batteries, and its capacitive power capability and cycle life is on par with supercapacitors (SCs). Therefore, this lithium-ion hybrid capacitor is expected to bridge the gap between Li-ion battery and SCs and gain bright prospects in next-generation energy storage fields.

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