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1.
Small ; : e2401849, 2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38682728

RESUMO

Manganese dioxide (MnO2) materials have recently garnered attention as prospective high-capacity cathodes, owing to their theoretical two-electron redox reaction in charge storage processes. However, their practical application in aqueous energy storage systems faces a formidable challenge: the disproportionation of Mn3+ ions, leading to a significant reduction in their capacity. To address this limitation, the study presents a novel graphitic carbon interlayer-engineered manganese oxide (CI-MnOx) characterized by an open structure and abundant defects. This innovative material serves several essential functions for efficient aqueous energy storage. First, a graphitic carbon layer coats the MnOx molecular interlayer, effectively inhibiting Mn3+ disproportionation and substantially enhancing electrode conductivity. Second, the phase variation within MnOx generates numerous crystal defects, vacancies, and active sites, optimizing electron-transfer capability. Third, the flexible carbon layer acts as a buffer, mitigating the volume expansion of MnOx during extended cycling. The synergistic effects of these features result in the CI-MnOx exhibiting an impressive high capacity of 272 mAh g-1 (1224 F g-1) at 0.25 A g-1. Notably, the CI-MnOx demonstrates zero capacity loss after 90 000 cycles (≈3011 h), an uncommon longevity for manganese oxide materials. Spectral characterizations reveal reversible cation intercalation and conversion reactions with multielectron transfer in a LiCl electrolyte.

2.
Materials (Basel) ; 17(6)2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38541570

RESUMO

Aqueous supercapacitors have occupied a significant position among various types of stationary energy storage equipment, while their widespread application is hindered by the relatively low energy density. Herein, N/F co-doped carbon materials activated by manganese clusters (NCM) are constructed by the straightforward experimental routine. Benefiting from the elevated conductivity structure at the microscopic level, the optimized NCM-0.5 electrodes exhibited a remarkable specific capacitance of 653 F g-1 at 0.4 A g-1 and exceptional cycling stability (97.39% capacity retention even after 40,000 cycles at the scanning rate of 100 mV s-1) in a neutral 5 M LiCl electrolyte. Moreover, we assembled an asymmetric device pairing with a VOx anode (NCM-0.5//VOx), which delivered a durable life span of 95% capacity retention over 30,000 cycles and an impressive energy density of 77.9 Wh kg-1. This study provides inspiration for transition metal element doping engineering in high-energy storage equipment.

3.
Signal Transduct Target Ther ; 9(1): 45, 2024 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-38374140

RESUMO

Cardiac fibroblasts (CFs) are the primary cells tasked with depositing and remodeling collagen and significantly associated with heart failure (HF). TEAD1 has been shown to be essential for heart development and homeostasis. However, fibroblast endogenous TEAD1 in cardiac remodeling remains incompletely understood. Transcriptomic analyses revealed consistently upregulated cardiac TEAD1 expression in mice 4 weeks after transverse aortic constriction (TAC) and Ang-II infusion. Further investigation revealed that CFs were the primary cell type expressing elevated TEAD1 levels in response to pressure overload. Conditional TEAD1 knockout was achieved by crossing TEAD1-floxed mice with CFs- and myofibroblasts-specific Cre mice. Echocardiographic and histological analyses demonstrated that CFs- and myofibroblasts-specific TEAD1 deficiency and treatment with TEAD1 inhibitor, VT103, ameliorated TAC-induced cardiac remodeling. Mechanistically, RNA-seq and ChIP-seq analysis identified Wnt4 as a novel TEAD1 target. TEAD1 has been shown to promote the fibroblast-to-myofibroblast transition through the Wnt signalling pathway, and genetic Wnt4 knockdown inhibited the pro-transformation phenotype in CFs with TEAD1 overexpression. Furthermore, co-immunoprecipitation combined with mass spectrometry, chromatin immunoprecipitation, and luciferase assays demonstrated interaction between TEAD1 and BET protein BRD4, leading to the binding and activation of the Wnt4 promoter. In conclusion, TEAD1 is an essential regulator of the pro-fibrotic CFs phenotype associated with pathological cardiac remodeling via the BRD4/Wnt4 signalling pathway.


Assuntos
Fatores de Transcrição de Domínio TEA , Fatores de Transcrição , Remodelação Ventricular , Animais , Camundongos , Miofibroblastos/metabolismo , Miofibroblastos/patologia , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Fatores de Transcrição de Domínio TEA/genética , Fatores de Transcrição de Domínio TEA/metabolismo , Fatores de Transcrição/genética , Remodelação Ventricular/genética , Proteína Wnt4/metabolismo , Fibroblastos/metabolismo , Proteínas que Contêm Bromodomínio/metabolismo
4.
Small ; 20(6): e2306275, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37775936

RESUMO

Vanadium trioxide (V6 O13 ) cathode has recently aroused intensive interest for aqueous zinc-ion batteries (AZIBs) due to their structural and electrochemical diversities. However, it undergoes sluggish reaction kinetics and significant capacity decay during prolonged cycling. Herein, an oxygen-vacancy-reinforced heterojunction in V6 O13- x /reduced graphene oxide (rGO) cathode is designed through electrostatic assembly and annealing strategy. The abundant oxygen vacancies existing in V6 O13- x weaken the electrostatic attraction with the inserted Zn2+ ; the external electric field constructed by the heterointerfaces between V6 O13- x and rGO provides additional built-in driving force for Zn2+ migration; the oxygen-vacancy-enriched V6 O13- x highly dispersed on rGO fabricates the interconnected conductive network, which achieves rapid Zn2+ migration from heterointerfaces to lattice. Consequently, the obtained 2D heterostructure exhibits a remarkable capacity of 424.5 mAh g-1 at 0.1 A g-1 , and a stable capacity retention (96% after 5800 cycles) at the fast discharge rate of 10 A g-1 . Besides, a flexible pouch-type AZIB with real-life practicability is fabricated, which can successfully power commercial products, and maintain stable zinc-ion storage performances even under bending, heavy strikes, and pressure condition. A series of quantitative investigation of pouch batteries demonstrates the possibility of pushing pouch-type AZIBs to realistic energy storage market.

5.
Proc Natl Acad Sci U S A ; 120(42): e2302482120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37816050

RESUMO

Myocardial infarction (MI) is a leading cause of heart failure (HF), associated with morbidity and mortality worldwide. As an essential part of gene expression regulation, the role of alternative polyadenylation (APA) in post-MI HF remains elusive. Here, we revealed a global, APA-mediated, 3' untranslated region (3' UTR)-lengthening pattern in both human and murine post-MI HF samples. Furthermore, the 3' UTR of apoptotic repressor gene, AVEN, is lengthened after MI, contributing to its downregulation. AVEN knockdown increased cardiomyocyte apoptosis, whereas restoration of AVEN expression substantially improved cardiac function. Mechanistically, AVEN 3' UTR lengthening provides additional binding sites for miR-30b-5p and miR-30c-5p, thus reducing AVEN expression. Additionally, PABPN1 (poly(A)-binding protein 1) was identified as a potential regulator of AVEN 3' UTR lengthening after MI. Altogether, our findings revealed APA as a unique mechanism regulating cardiac injury in response to MI and also indicated that the APA-regulated gene, AVEN, holds great potential as a critical therapeutic target for treating post-MI HF.


Assuntos
Traumatismos Cardíacos , MicroRNAs , Infarto do Miocárdio , Animais , Humanos , Camundongos , Regiões 3' não Traduzidas/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Regulação para Baixo , Traumatismos Cardíacos/genética , Proteínas de Membrana/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Miócitos Cardíacos/metabolismo , Proteína I de Ligação a Poli(A)
6.
J Nanobiotechnology ; 21(1): 190, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37312106

RESUMO

Developing an antibiotic-free wound dressing with effective hemostasis and antibacterial and antioxidant capacity is highly desirable. In this work, a three-dimensional (3D) chitosan/polyvinyl alcohol-tannic acid porous nanofiber sponge (3D-TA) was prepared via electrospinning. Compared with two-dimensional (2D) fiber membrane, the unique fluffy 3D-TA nanofiber sponge had high porosity, water absorption and retention ability, hemostatic capacity. Furthermore, the 3D sponge functionalized by tannic acid (TA) endow the sponge with high antibacterial and antioxidant capacity without loading antibiotics. In addition, 3D-TA composite sponges have shown highly biocompatibility against L929 cells. The in vivo experiment shows the 3D-TA is enable to accelerate wound healing. This newly 3D-TA sponges hold great potential as wound dressings for future clinical application.


Assuntos
Nanofibras , Antibacterianos/química , Porosidade , Nanofibras/química , Cicatrização , Antioxidantes/química , Hemostasia , Animais , Camundongos , Linhagem Celular
8.
Biomed Mater ; 18(3)2023 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-37001530

RESUMO

The fabrication of functional wound dressing for effective hemostasis, anti-inflammation as well as angiogenesis is of vital importance. In this paper, a three-dimensional (3D) nanofiber sponge with dimethyloxaloglycine (DMOG) loaded mesoporous spheres of derivatives of Prussian blue analogues (PBAs) was prepared (3D-PBAFeCo-DMOG). The nanostructure, composition, and mechanical properties of 3D-PBAFeCo-DMOG were characterized, showing regular nanostructure and good mechanical property. The behavior ofin vitrodrug release showed the DMOG could achieve long-term and stable release by encapsulating in PBAFeComicrospheres and nanofibers.In vitrocoagulation experiments showed that 3D-PBAFeCo-DMOG had effective hemostasis and clotting capacities. In addition, the antioxidant capacity and cell compatibility of 3D-PBAFeCo-DMOG were confirmed. These results indicate that 3D-PBAFeCo-DMOG nanofiber sponge, as a controlled drug release system, may provide a new strategy for promoting angiogenesis and wound healing for clinical applications.


Assuntos
Nanofibras , Nanofibras/química , Microesferas , Cicatrização , Bandagens
9.
Biochim Biophys Acta Gene Regul Mech ; 1866(1): 194898, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36403753

RESUMO

Histone epigenetic modifications are chemical modification changes to histone amino acid residues that modulate gene expression without altering the DNA sequence. As both the phenotypic and causal factors, cardiac metabolism disorder exacerbates mitochondrial ATP generation deficiency, thus promoting pathological cardiac hypertrophy. Moreover, several concomitant metabolic substrates also promote the expression of hypertrophy-responsive genes via regulating histone modifications as substrates or enzyme-modifiers, indicating their dual roles as metabolic and epigenetic regulators. This review focuses on the cardiac acetyl-CoA-dependent histone acetylation, NAD+-dependent SIRT-mediated deacetylation, FAD+-dependent LSD-mediated, and α-KG-dependent JMJD-mediated demethylation after briefly addressing the pathological and physiological cardiac energy metabolism. Besides using an "iceberg model" to explain the dual role of metabolic substrates as both metabolic and epigenetic regulators, we also put forward that the therapeutic supplementation of metabolic substrates is promising to blunt HF via re-establishing histone modifications.


Assuntos
Insuficiência Cardíaca , Histonas , Humanos , Histonas/metabolismo , Código das Histonas , Insuficiência Cardíaca/genética , Insuficiência Cardíaca/tratamento farmacológico , Processamento de Proteína Pós-Traducional , Metilação
10.
Am Psychol ; 77(6): 786-788, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-36074572

RESUMO

By examining the changes in the conceptual associations between individualism-collectivism and 10 other concepts based on the Google Ngram Chinese Corpus from the 1950s to the 1990s, Hamamura et al. (2021) inferred (a) no rise in individualism; (b) continuing collectivism; and (c) no effect of modernization on individualism in contemporary China. We question the validity of these conclusions given the following issues in their research: (a) misinterpretation of statistical results; (b) improper calculation of cultural associations; and (c) inappropriate generalization of specific findings. Contrary to their original findings, our reanalysis of their data suggests that individualism has been increasingly accepted and associated with some positive (vs. negative) aspects of life (e.g., income vs. loss, richness vs. poverty) over recent decades in China. Future research should use more rigorous methods and diverse corpora to clarify and explain changes in individualism and collectivism in China. (PsycInfo Database Record (c) 2022 APA, all rights reserved).


Assuntos
Individualidade , Mudança Social , China
11.
EBioMedicine ; 78: 103968, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35367772

RESUMO

Myocardial infarction is lethal to patients because of insufficient blood perfusion to vital organs. Several attempts have been made to improve its prognosis, among which nanomaterial research offers an opportunity to address this problem at the molecular level and has the potential to improve disease prevention, diagnosis, and treatment significantly. Up to now, nanomaterial-based technology has played a crucial role in broad novel diagnostic and therapeutic strategies for cardiac repair. This review summarizes various nanomaterial applications in myocardial infarction from multiple aspects, including high precision detection, pro-angiogenesis, regulating immune homeostasis, and miRNA and stem cell delivery vehicles. We also propose promising research hotspots that have not been reported much yet, such as conjugating pro-angiogenetic elements with nanoparticles to construct drug carriers, developing nanodrugs targeting other immune cells except for macrophages in the infarcted myocardium or the remote region. Though most of those strategies are preclinical and lack clinical trials, there is tremendous potential for their further applications in the future.


Assuntos
Infarto do Miocárdio , Nanopartículas , Portadores de Fármacos , Humanos , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/etiologia , Infarto do Miocárdio/terapia , Miocárdio , Células-Tronco/fisiologia
12.
Small ; : e2004709, 2020 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-33289327

RESUMO

Intrinsic defects, including oxygen vacancies, can efficiently modify the electrochemical performance of metal oxides. There is, however, a limited understanding of how vacancies influence charge storage properties. Here, using tungsten oxide as a model system, an extensive study of the effects of structure, electrical properties, and charge storage properties of oxygen vacancies is carried out using both experimental and computational techniques. The results provide direct evidence that oxygen vacancies increase the interlayer spacing in the oxide, which suppress the structural pulverization of the material during electrolyte ion insertion and removal in prolonged stability tests. Specifically, no capacitive decay is detected after 30 000 cycles. The medium states and charge storage mechanism of oxygen-deficient tungsten oxide throughout electrochemical charging/discharging processes is studied. The enhanced rate capability of the oxygen-deficient WO3- x is attributed to improved charge storage kinetics in the bulk material. The WO3- x electrode exhibits the highest capacitance in reported tungsten-oxide based electrodes with comparable mass loadings. The capability to improve electrochemical capacitance performance of redox-active materials is expected to open up new opportunities for ultrafast supercapacitive electrodes.

13.
ACS Appl Mater Interfaces ; 12(32): 36072-36081, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32700891

RESUMO

Rechargeable aqueous Zn-MnO2 batteries using a mild electrolyte have attracted considerable interest because of their high output voltage, high safety, low cost, and environmental friendliness. However, poor cycling stability remains a significant issue for their applications. Equally, the energy storage mechanism involved is still controversial thus far. Herein, porous polyfurfural/MnO2 (PFM) nanocomposites are prepared via a facile one-step method. When tested in a rechargeable aqueous Zn-MnO2 cell, the PFM nanocomposites deliver high specific capacity, considerable rate performance, and excellent long-term cyclic stability. Based on the experimental results, the role of the hydrated basic zinc sulfate layer being linked to the cycling stability of the aqueous rechargeable zinc-ion batteries is revealed. The mechanistic details of the insertion reaction based on the H+ ion storage mechanism are proposed, which plays a crucial role in maintaining the cycling performance of the rechargeable aqueous Zn-MnO2 cell. We expect that this work will provide an insight into the energy storage mechanism of MnO2 in aqueous systems and pave the way for the design of long-term cycling stable electrode materials for rechargeable aqueous Zn-MnO2 batteries.

14.
FASEB J ; 34(6): 8442-8458, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32350913

RESUMO

Pancreatic cancer is the fourth most lethal malignancy and is characterized by poor immunogenicity. Pancreatic cancer cells have various strategies to suppress host immune response, evade immune defenses, and facilitate tumor growth and development. As a mode of long-range intercellular communication, cancer-derived exosomes contribute to impairment of the immune system. However, the mechanisms that induce changes in the activities of signal transduction pathways in immune cells, which are influenced by tumor-derived exosomes, are poorly understood. We (1) treated peripheral T lymphocytes with pancreatic cancer-derived exosomes, tagged CD63 with tdTomato, to trace exosome transfer from pancreatic cancer cells to T lymphocytes; (2) carried out a cytotoxicity assay of exosome-treated T lymphocytes using the Real Time Cellular Analysis system; (3) performed RNA sequencing and gene set enrichment analysis to explore the pivotal signaling pathway that mediates apoptosis in exosome-treated T lymphocytes; and (4) demonstrated the role of p38 mitogen-activated protein kinase (MAPK) and endoplasmic reticulum (ER) stress in exosome-induced T-lymphocyte apoptosis. In conclusion, these results indicate that pancreatic cancer cells secrete exosomes, which are taken up by T lymphocytes to activate p38 MAPK, and then induce ER stress-mediated apoptosis, ultimately causing immunosuppression.


Assuntos
Apoptose/fisiologia , Estresse do Retículo Endoplasmático/fisiologia , Exossomos/metabolismo , Neoplasias Pancreáticas/metabolismo , Linfócitos T/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Linhagem Celular , Linhagem Celular Tumoral , Humanos , Células PC-3 , Transdução de Sinais/fisiologia
15.
Nanomicro Lett ; 12(1): 133, 2020 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-34138093

RESUMO

Electrocatalytic nitrogen reduction reaction is a carbon-free and energy-saving strategy for efficient synthesis of ammonia under ambient conditions. Here, we report the synthesis of nanosized Bi2O3 particles grown on functionalized exfoliated graphene (Bi2O3/FEG) via a facile electrochemical deposition method. The obtained free-standing Bi2O3/FEG achieves a high Faradaic efficiency of 11.2% and a large NH3 yield of 4.21 ± 0.14 [Formula: see text] h-1 cm-2 at - 0.5 V versus reversible hydrogen electrode in 0.1 M Na2SO4, better than that in the strong acidic and basic media. Benefiting from its strong interaction of Bi 6p band with the N 2p orbitals, binder-free characteristic, and facile electron transfer, Bi2O3/FEG achieves superior catalytic performance and excellent long-term stability as compared with most of the previous reported catalysts. This study is significant to design low-cost, high-efficient Bi-based electrocatalysts for electrochemical ammonia synthesis.

16.
Huan Jing Ke Xue ; 40(12): 5604-5614, 2019 Dec 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854633

RESUMO

The Guangdong-Hong Kong-Macau Greater Bay Area presents the highest number of electroplating corporations in China; some of them of very large scale. Electroplating emissions are the cause of widespread heavy metal contamination of both soil and groundwater in the Guangdong-Hong Kong-Macau Greater Bay Area. Hence, the reuse of electroplating sites in this area should be preceded by an analysis of heavy metal characteristics and migration in the soil and groundwater. We performed such analyses in correspondence of a relocated electroplating site on the hilly lands of the Guangdong-Hong Kong-Macau Greater Bay Area, and quantitatively determined the spatial distribution of heavy metals. Moreover, we discussed the migration of heavy metals under the specific hydrogeological conditions of the area. The results showed that the soil and groundwater in correspondence of the electroplating factory were polluted by heavy metals in different degrees. The over-standard rates of Ni, Cr6+, and Cu in the soil were 20.5%, 12.8%, and 2.7%, respectively; meanwhile, those of Ni, Pb, and Cr6+ in the groundwater were 41.7%, 33.3%, and 33.3%, respectively. The pattern of heavy metal pollution reflected the functional division of the electroplating factory, the contaminants should have mainly derived from the leakage of electroplating wastes. A low-permeable silt clay layer located below the fill soil layer limited the downward transportation of heavy metals, which were hence mainly concentrated in the surface soils. However, in another area of the site characterized by shallow-buried and completely decomposed granite (having high permeability), heavy metals could be transported much deeper. The adsorption of Cr6+ by the soil tends to be weak in an acid-acidic environment, explaining the relatively high concentrations of Cr6+ recorded in the upper 10 m of soil. Although the conductivity of the shallow aquifers was low, the occurrence of acid soil and of an oxidizing water environment should have favored the transport of Cr6+ and Ni in the groundwater, causing high concentrations of Cr6+ and Ni in correspondence of the electroplating workshops (characterized by a relatively low water table and deep heavy metal transport depth). The excess of Pb in the groundwater probably resulted from the high Pb content of granite in the Guangdong-Hong Kong-Macau Greater Bay Area. Overall, we observed high concentrations of Ni, Cr6+, and Cu in the shallow soil and groundwater located in correspondence of the electroplating site on the hilly lands of the Guangdong-Hong Kong-Macau Greater Bay Area. The presence of low permeable clay restricted the downward diffusion of heavy metals. However, in the presence of acid soil and shallow buried granite, or of oxidized groundwater, the migration depth of Ni and Cr6+ was significantly higher.

17.
Cogn Affect Behav Neurosci ; 19(2): 327-337, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30488229

RESUMO

We proposed that self-affirmation can endow people with more cognitive resource to cope with uncertainty. We tested this possibility with an event-related potential (ERP) study by examining how self-affirmation influences ambiguous feedback processing in a simple gambling task, which was used to investigate risk decision-making. We assigned 48 participants randomly to the affirmation and non-affirmation (i.e., control) groups. All participants accepted the manipulation first and then completed the gambling task with an electroencephalogram (EEG) recording, in which participants might receive a positive (winning), negative (losing), or ambiguous (unknown valence) outcome after they made a choice. We considered both the feedback-related negativity (FRN) and P3 components elicited by the outcome feedback, which reflected the amount of cognitive resources being invested in the early and late stages of the outcome feedback processing, respectively. ERP results showed that ambiguous feedback elicited a larger FRN among affirmed participants than unaffirmed participants but exerted no influence on the P3. This finding suggests that self-affirmation may help coping with uncertainty by enhancing the early processing of uncertainty.


Assuntos
Encéfalo/fisiologia , Tomada de Decisões/fisiologia , Autoimagem , Incerteza , Adulto , Afeto , Eletroencefalografia , Potenciais Evocados , Feminino , Humanos , Masculino , Valores Sociais , Adulto Jovem
18.
ACS Nano ; 12(4): 3557-3567, 2018 04 24.
Artigo em Inglês | MEDLINE | ID: mdl-29579384

RESUMO

Metal oxides have attracted renewed interest as promising electrode materials for high energy density supercapacitors. However, the electrochemical performance of metal oxide materials deteriorates significantly with the increase of mass loading due to their moderate electronic and ionic conductivities. This limits their practical energy. Herein, we perform a morphology and phase-controlled electrodeposition of MnO2 with ultrahigh mass loading of 10 mg cm-2 on a carbon cloth substrate to achieve high overall capacitance without sacrificing the electrochemical performance. Under optimum conditions, a hierarchical nanostructured architecture was constructed by interconnection of primary two-dimensional ε-MnO2 nanosheets and secondary one-dimensional α-MnO2 nanorod arrays. The specific hetero-nanostructures ensure facile ionic and electric transport in the entire electrode and maintain the structure stability during cycling. The hierarchically structured MnO2 electrode with high mass loading yields an outstanding areal capacitance of 3.04 F cm-2 (or a specific capacitance of 304 F g-1) at 3 mA cm-2 and an excellent rate capability comparable to those of low mass loading MnO2 electrodes. Finally, the aqueous and all-solid asymmetric supercapacitors (ASCs) assembled with our MnO2 cathode exhibit extremely high volumetric energy densities (8.3 mWh cm-3 at the power density of 0.28 W cm-3 for aqueous ASC and 8.0 mWh cm-3 at 0.65 W cm-3 for all-solid ASC), superior to most state-of-the-art supercapacitors.

19.
Nanoscale ; 9(35): 13119-13127, 2017 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-28849857

RESUMO

Heteroatom-doped carbonaceous materials derived from polymers are emerging as a new class of promising supercapacitor electrodes. These electrodes have both electrical double layer capacitance (from carbon matrices) and pseudo-capacitance (from hetero-atoms). Balancing the electrical double layer capacitance and pseudo-capacitance is a key to achieve large capacitance at ultrafast current densities. Here we investigate the influence of pyrolysis temperature on capacitive performance of hetero-atom (oxygen and nitrogen) doped carbons derived from polypyrrole nanowire arrays. Structural and electrochemical characterization reveal that the concentration of hetero-atoms as well as the ratio of electrical double layer capacitance and pseudo-capacitance can be tuned by varying the pyrolysis temperature. In fact the hetero-atom doped carbon sample obtained at a relatively lower pyrolysis temperature (500 °C) exhibits the optimal capacitive performance. It yields an outstanding areal capacitance of 324 mF cm-2 at 1 mA cm-2 (141 F g-1@0.43 A g-1), and more importantly, retains an areal capacitance of 184.7 mF cm-2 (80.3 F g-1@43.5 A g-1) at an ultrahigh current density of 100 mA cm-2. An asymmetric supercapacitor consisting of hetero-atom doped carbon as an anode delivers a maximum volumetric energy density of 1.7 mW h cm-3 at a volumetric power density of 0.014 W cm-3, which is among the best values reported for asymmetric supercapacitors.

20.
ACS Appl Mater Interfaces ; 7(45): 25506-13, 2015 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-26509281

RESUMO

Highly aligned nanoarchitecture arrays directly grown on conducting substrates open up a new direction to accelerate Faradaic reactions for charge storage as well as address "dead volume" limitations for high-performance pseudocapacitor electrodes. Here we reported the electrochemical fabrication of well-ordered polypyrrole (PPy) nanowire arrays (NWAs) on surfaces of carbon fibers in an untreated carbon cloth to construct hierarchical structures constituted by the three-dimensional conductive carbon fiber skeleton and the atop well-ordered electroactive polymer nanowires. The morphologies, wetting behaviors, and charge-storage performances of the polymer were investigated by scanning electron microscopy, transmission electron microscopy, contact-angle measurement, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. The well-ordered PPy NWA electrode exhibited a high specific capacitance of 699 F/g at 1 A/g with excellent rate capability, and 92.4% and 81.5% of its capacitance could be retained at 10 and 20 A/g, respectively. An extremely high energy density of 164.07 Wh/kg could be achieved by the PPy NWAs at a power density of 0.65 kW/kg. It also displayed a quite high energy density of 133.79 Wh/kg at a high power density of 13 kW/kg. The assembled symmetric supercapacitor of PPy NWAs//PPy NWAs also exhibited excellent rate capability, and only 19% of its energy density decreased when the power density increased 20 times from 0.65 to 13 kW/kg.

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