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1.
Ultrason Sonochem ; 100: 106620, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37757600

RESUMEN

Lithium-ion batteries (LIBs) stand as a compelling solution to energy source transition in various applications such as the vehicle industry due to their energy and power density. However, the impact of mechanical factors on them remains understudied. Of particular interest is the effect of vibration, an inherent characteristic of vehicles, on battery performance. Ultrasound has been reported to improve mass transfer and surface cleaning, yet its effects on LIBs are still not thoroughly investigated. This study investigates the influence of ultrasound on the solid electrolyte interphase (SEI) layer, resulting in a thin, inorganic-rich layer. The induced SEI layer alteration improves charge transfer, showing enhanced kinetics. We also reveal that ultrasound application enhances cycling stability, maintains discharge capacity at high charging rates, and facilitates inorganic-rich SEI layer creation. This novel combination of ultrasound and LIBs presents a promising pathway for achieving high-performance batteries.

2.
ACS Nano ; 14(5): 5659-5667, 2020 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-32379413

RESUMEN

Soft energy storage devices, such as supercapacitors, are an essential component for powering integrated soft microsystems. However, conventional supercapacitors are mainly manufactured using hard/brittle materials that easily crack and eventually delaminate from the current collector by mechanical deformation. Therefore, to realize all-soft supercapacitors, the electrodes should be soft, stretchable, and highly conductive without compromising the electrochemical performance. This paper presents all-soft supercapacitors for integrated soft microsystems based on gallium-indium liquid metal (eutectic gallium-indium alloy, EGaIn) electrodes with integrated functionalized carbon nanotubes (CNTs). Oxygen functional groups on the surface of the CNTs ensure strong adhesion between the functionalized CNTs and the thin native oxide layer on the surface of EGaIn, which enables delamination-free soft and stretchable electrodes even under mechanical deformation. The electrochemical performances of fabricated all-soft supercapacitors in a parallel-plate arrangement were investigated without and with applied mechanical deformation. The fabricated supercapacitors exhibit areal capacitances as high as 12.4 mF cm-2 and show nearly unchanged performance under 30% applied strain. They maintain >95% of their original capacitance after >4200 charging and discharging cycles with a periodic applied strain of 30%. Finally, fabricated supercapacitors have been successfully integrated with a commercial light-emitting diode to demonstrate an integrated soft microsystem.

3.
Adv Mater ; 31(33): e1903316, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31243820

RESUMEN

To achieve excellent photoelectrochemical water-splitting activity, photoanode materials with high light absorption and good charge-separation efficiency are essential. One effective strategy for the production of materials satisfying these requirements is to adjust their band structure and corresponding bandgap energy by introducing oxygen vacancies. A simple chemical reduction method that can systematically generate oxygen vacancies in barium stannate (BaSnO3 (BSO)) crystal is introduced, which thus allows for precise control of the bandgap energy. A BSO photoanode with optimum oxygen-vacancy concentration (8.7%) exhibits high light-absorption and good charge-separation capabilities. After deposition of FeOOH/NiOOH oxygen evolution cocatalysts on its surface, this photoanode shows a remarkable photocurrent density of 7.32 mA cm-2 at a potential of 1.23 V versus a reversible hydrogen electrode under AM1.5G simulated sunlight. Moreover, a tandem device constructed with a perovskite solar cell exhibits an operating photocurrent density of 6.84 mA cm-2 and stable gas production with an average solar-to-hydrogen conversion efficiency of 7.92% for 100 h, thus functioning as an outstanding unbiased water-splitting system.

4.
Adv Mater ; 31(32): e1901977, 2019 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-31192497

RESUMEN

It is crucial for leaping forward renewable energy technology to develop highly active oxygen evolution reaction (OER) catalysts with fast OER kinetics, and the novel design of high-performance catalysts may come down to unveiling the origin of high catalytic behavior. Herein, a new class of heterogeneous OER electrocatalyst (metallic Co nanoparticles anchored on yttrium ruthenate pyrochlore oxide) is provided for securing fast OER kinetics. In situ X-ray absorption spectroscopy (in situ XAS) reveals that fast OER kinetics can be achieved by the harmonious catalytic synergy of a pyrochlore oxide support to Co nanoparticles. By the facile oxidation of yttrium (A-site) and ruthenium (B-site) cations, the pyrochlore oxide support helps to expel the electrons generated from the catalytic behavior of Co to the inner layers of the support, facilitating the electrostatic adsorption of OH- ions and reducing the barrier energy for the formation of CoOOH intermediates. This work affords the rational design of transition metal nanoparticles anchored on pyrochlore oxide heterogeneous catalysts and the fundamental insight of catalytic origin associated with self-reconstruction of OER electrocatalysts.

5.
Chem Rev ; 119(8): 5416-5460, 2019 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-30946573

RESUMEN

This comprehensive Review focuses on the key challenges and recent progress regarding sodium-metal anodes employed in sodium-metal batteries (SMBs). The metal anode is the essential component of emerging energy storage systems such as sodium sulfur and sodium selenium, which are discussed as example full-cell applications. We begin with a description of the differences in the chemical and physical properties of Na metal versus the oft-studied Li metal, and a corresponding discussion regarding the number of ways in which Na does not follow Li-inherited paradigms in its electrochemical behavior. We detail the major challenges for Na-metal systems that at this time limit the feasibility of SMBs. The core Na anode problems are the following interrelated degradation mechanisms: An unstable solid electrolyte interphase with most organic electrolytes, "mossy" and "lath-like" metal dendrite growth for liquid systems, poor Coulombic efficiency, and gas evolution. Even solid-state Na batteries are not immune, with metal dendrites being reported. The solutions may be subdivided into the following interrelated taxonomy: Improved electrolytes and electrolyte additives tailored for Na-metal anodes, interfacial engineering between the metal and the liquid or solid electrolyte, electrode architectures that both reduce the current density during plating-stripping and serve as effective hosts that shield the Na metal from excessive reactions, and alloy design to tune the bulk properties of the metal per se. For instance, stable plating-stripping of Na is extremely difficult with conventional carbonate solvents but has been reported with ethers and glymes. Solid-state electrolytes (SSEs) such as beta-alumina solid electrolyte (BASE), sodium superionic conductor (NASICON), and sodium thiophosphate (75Na2S·25P2S5) present highly exciting opportunities for SMBs that avoid the dangers of flammable liquids. Even SSEs are not immune to dendrites, however, which grow through the defects in the bulk pellet, but may be controlled through interfacial energy modification. We conclude with a discussion of the key research areas that we feel are the most fruitful for further pursuit. In our opinion, greatly improved understanding and control of the SEI structure is the key to cycling stability. A holistic approach involving complementary post-mortem, in situ, and operando analyses to elucidate full battery cell level structure-performance relations is advocated.


Asunto(s)
Suministros de Energía Eléctrica , Técnicas Electroquímicas/instrumentación , Sodio/química , Técnicas Electroquímicas/métodos , Electrodos
6.
Small ; 14(34): e1801236, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30063293

RESUMEN

Polydopamine, a functional coating material, is redox active as cathode materials for both Li- and Na-ion batteries or hybrid capacitors. Here, a polydopamine coating onto 3D graphene framework is introduced through a simple hydrothermal process, during which graphene oxide serves not only as an oxidant for assisting the polymerization of dopamine, but also as a template for the conformal growth of polydopamine. High-density films are fabricated by compressing the polydopamine-coated graphene aerogels, which can be directly used as free-standing and flexible cathodes in both Li- and Na-cells. The compact electrodes deliver high capacities of ≈230 mAh g-1 in Li-cells and ≈211 mAh g-1 in Na-cells based on the total mass of electrodes. These compact electrodes also exhibit exceptional cycling stability and high rate performance due to the unique structure in which polydopamine is uniformly coated on the 3D structured graphene.


Asunto(s)
Dopamina/química , Suministros de Energía Eléctrica , Grafito/química , Polimerizacion , Técnicas Electroquímicas , Indoles/química , Espectroscopía de Fotoelectrones , Polímeros/química
7.
Small ; 14(35): e1801948, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-30073794

RESUMEN

Nanostructured graphene electrodes generally have a low density, which can limit the volumetric performance for energy storage devices. The liquid-phase mild reduction process of graphene oxide sheets is combined with the continuous aerosol densification process to produce high-density graphene agglomerates in the form of microspheres. The produced graphene assembly shows the cabbage-like morphology with a high density of 0.75 g cm-3 . In spite of such high density, the cabbage-like graphene microspheres have narrow-ranged mesopores and a high surface area. The cabbage-like graphene microsphere exhibits both high gravimetric and volumetric energy densities due to the optimized microstructure, which shows a high gravimetric capacitance of 177 F g-1 and volumetric capacitance of 117 F cm-3 in supercapacitors. As a cathode for lithium-ion capacitors, the cabbage-like graphene delivers a reversible capacity of ≈176 mAh g-1 . The stacking-control approach provides a new pathway to control the microstructure of the graphene assembly and corresponding charge storage characteristics for energy storage applications.

8.
Nat Commun ; 8(1): 536, 2017 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-28912562

RESUMEN

The effective implantation of conductive and charge storage materials into flexible frames has been strongly demanded for the development of flexible supercapacitors. Here, we introduce metallic cellulose paper-based supercapacitor electrodes with excellent energy storage performance by minimizing the contact resistance between neighboring metal and/or metal oxide nanoparticles using an assembly approach, called ligand-mediated layer-by-layer assembly. This approach can convert the insulating paper to the highly porous metallic paper with large surface areas that can function as current collectors and nanoparticle reservoirs for supercapacitor electrodes. Moreover, we demonstrate that the alternating structure design of the metal and pseudocapacitive nanoparticles on the metallic papers can remarkably increase the areal capacitance and rate capability with a notable decrease in the internal resistance. The maximum power and energy density of the metallic paper-based supercapacitors are estimated to be 15.1 mW cm-2 and 267.3 µWh cm-2, respectively, substantially outperforming the performance of conventional paper or textile-type supercapacitors.With ligand-mediated layer-by-layer assembly between metal nanoparticles and small organic molecules, the authors prepare metallic paper electrodes for supercapacitors with high power and energy densities. This approach could be extended to various electrodes for portable/wearable electronics.

9.
Nanoscale ; 8(24): 12330-8, 2016 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-27273722

RESUMEN

Crumpled graphene is known to have a strong aggregation-resistive property due to its unique 3D morphology, providing a promising solution to prevent the restacking issue of graphene based electrode materials. Here, we demonstrate the utilization of redox-active oxygen functional groups on the partially reduced crumpled graphene oxide (r-CGO) for electrochemical energy storage applications. To effectively utilize the surface redox reactions of the functional groups, hierarchical networks of electrodes including r-CGO and functionalized few-walled carbon nanotubes (f-FWNTs) are assembled via a vacuum-filtration process, resulting in a 3D porous structure. These composite electrodes are employed as positive electrodes in Li-cells, delivering high gravimetric capacities of up to ∼170 mA h g(-1) with significantly enhanced rate-capability compared to the electrodes consisting of conventional 2D reduced graphene oxide and f-FWNTs. These results highlight the importance of microstructure design coupled with oxygen chemistry control, to maximize the surface redox reactions on functionalized graphene based electrodes.

10.
Eur Neuropsychopharmacol ; 16(2): 123-8, 2006 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-16125912

RESUMEN

One hundred and eleven male patients with alcohol dependence and 123 nonalcoholic healthy men were tested for the genetic polymorphisms of alcohol dehydrogenase 2 (ADH2), aldehyde dehydrogenase 2 (ALDH2), serotonin transporter (5-HTT) and dopamine transporter (DAT1). There were significant differences in genotype frequencies of ADH2 C992G and A13543G SNPs between alcoholic patients with family history of alcohol dependence (familial) and alcoholic patients without family history (non-familial). Genotype and allele frequencies of ALDH2 G1951A SNP in familial or non-familial alcoholic patients differ from normal controls. Neither 5-HTTLPR L/S nor DAT1 G2319A SNP genotypes nor alleles discriminated alcoholic patients from normal controls. These findings suggest that the genetic characteristics of alcohol metabolism in non-familial alcoholics fall between non-alcoholism and familial alcoholics.


Asunto(s)
Alcohol Deshidrogenasa/genética , Alcoholismo/genética , Alcoholismo/metabolismo , Aldehído Deshidrogenasa/genética , Proteínas de Transporte de Dopamina a través de la Membrana Plasmática/genética , Polimorfismo Genético/genética , Proteínas de Transporte de Serotonina en la Membrana Plasmática/genética , Adulto , Alcoholismo/enzimología , Alelos , ADN/genética , Familia , Frecuencia de los Genes , Genotipo , Humanos , Isoenzimas/genética , Corea (Geográfico)/epidemiología , Masculino , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa
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