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1.
J Colloid Interface Sci ; 607(Pt 2): 1153-1162, 2021 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-34571302

RESUMO

Transition metal oxalates have attracted wide attention due to the characteristics of the conversion reaction as anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), However, there are huge volume expansion and sluggish circulation dynamics during the reversible Li+ and Na+ insertion/extraction process, which would lead to unsatisfactory reversible capacity and stability. In order to solve these problems, a rod-like structure Ni0.5Co0.5C2O4·2H2O is in-situ formed on the reduced graphene oxide layer (Ni0.5Co0.5C2O4·2H2O/rGO) in a glycol-water mixture medium via an interface induced engineering strategy. Benefitting from the synergistic cooperation of nano-diameter rod-like structure and high conductive rGO networks, the experimental results show that the prepared Ni0.5Co0.5C2O4·2H2O/rGO electrode has predominant rate performance and ultra-long cycle stability. For the LIBs, it not only exhibits an ultrahigh reversible capacity (1179.9 mA h g-1 at 0.5 A g-1 after 300 cycles), but also presents outstanding rate and cycling performance (646.5 mA h g-1 at 5 A g-1 after 1200 cycles). Besides, the Ni0.5Co0.5C2O4·2H2O/rGO electrode displays remarkable sodium storage capacity of 221.6 mA h g-1 after 100 cycles at 0.5 A g-1. Further, the extraordinary electrochemical capability of Ni0.5Co0.5C2O4·2H2O/rGO active material is also reflected in two full-cells, assembled using commercial LiCoO2 as cathode for LIBs and commercial Na3V2(PO4)3 as cathode for SIBs, both of which can show wonderful specific capacity and cycling stability. It is found in in-situ Raman experiments that the reversible changes of oxalate peaks are monitored in a charge/discharge process, which is scientific evidence for the transform reaction mechanism of metal oxalates in LIBs. These findings not only provide important ideas for studying the charge/discharge storage mechanism but also give scientific basis for the design of high-performance electrode materials.

2.
Science ; 373(6552): 337-342, 2021 07 16.
Artigo em Inglês | MEDLINE | ID: mdl-34437153

RESUMO

Piezoelectric biomaterials are intrinsically suitable for coupling mechanical and electrical energy in biological systems to achieve in vivo real-time sensing, actuation, and electricity generation. However, the inability to synthesize and align the piezoelectric phase at a large scale remains a roadblock toward practical applications. We present a wafer-scale approach to creating piezoelectric biomaterial thin films based on γ-glycine crystals. The thin film has a sandwich structure, where a crystalline glycine layer self-assembles and automatically aligns between two polyvinyl alcohol (PVA) thin films. The heterostructured glycine-PVA films exhibit piezoelectric coefficients of 5.3 picocoulombs per newton or 157.5 × 10-3 volt meters per newton and nearly an order of magnitude enhancement of the mechanical flexibility compared with pure glycine crystals. With its natural compatibility and degradability in physiological environments, glycine-PVA films may enable the development of transient implantable electromechanical devices.


Assuntos
Materiais Biocompatíveis/química , Eletricidade , Glicina/química , Álcool de Polivinil/química , Animais , Sobrevivência Celular , Células Cultivadas , Cristalização , Teoria da Densidade Funcional , Elasticidade , Humanos , Ligação de Hidrogênio , Próteses e Implantes , Ratos , Ratos Sprague-Dawley , Estresse Mecânico
3.
ACS Nano ; 15(9): 14903-14914, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34405669

RESUMO

Three-dimensional (3D) ferroelectric materials are electromechanical building blocks for achieving human-machine interfacing, energy sustainability, and enhanced therapeutics. However, current natural or synthetic materials cannot offer both a high piezoelectric response and desired mechanical toughness at the same time to meet the practicality. Here, a lamellar ferroelectric metamaterial was created with a ceramic-like piezoelectric property and a bone-like fracture toughness through a low-voltage-assisted 3D printing technology. The one-step printed bulk structure, consisting of periodically intercalated soft ferroelectric and hard electrode layers, exhibited a significantly enhanced longitudinal piezoelectric charge coefficient (d33) of over 150 pC N-1, as well as a superior fracture resistance of ∼5.5 MPa·m1/2, more than three times higher than conventional piezo-ceramics. The excellent printability together with the combination of both high piezoelectric and mechanical behaviors allowed us to create a bone-like structure with tunable anisotropic piezoelectricity and bone-comparable mechanical properties, showing a potential of manufacturing practical, high-performance, and smart biological systems.


Assuntos
Biomimética , Humanos
4.
ACS Appl Mater Interfaces ; 13(12): 14275-14282, 2021 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-33729760

RESUMO

Bioresorbable implantable electronics require power sources that are also bioresorbable with controllable electrical output and lifetime. In this paper, we report a bioresorbable zinc primary battery anode filament based on a zinc microparticle (MP) network coated with chitosan and Al2O3 double shells. When discharged in 0.9% NaCl saline, a Zn MP filament with a 0.17 × 2 mm2 cross-sectional area exhibited a stable voltage output of 0.55 V at a current of 0.01 mA. Covered by chitosan and Al2O3 double shells, the zinc MP filament exhibited a directional dissolution behavior with a tunable lifetime approximately linear to its length. A stable 200 h discharging time was achieved with a 15 mm Zn MP filament. The maximum output power was found to be 12 µW at 0.03 mA for one filament. The linearity relationship between the current output and the filament cross-sectional area suggested a facile strategy to raise the power output at constant discharging voltage. The filaments could also be connected in series and in parallel to boost its overall voltage and current output, demonstrating their excellent integration capability. This work presents a promising pathway toward bioresorbable transient batteries with controllable lifetime and power output, demonstrating a great potential for powering transient implantable biomedical devices.

5.
Analyst ; 146(5): 1656-1662, 2021 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-33514956

RESUMO

Triboelectric nanogenerators (TENGs) have attracted many research endeavors as self-powered sensors for force, velocity, and gas detection based on solid-solid or solid-air interactions. Recently, triboelectrification at liquid-solid interfaces also showed intriguing capability in converting physical contacts into electricity. Here, we report a self-powered triboelectric sensor for liquid chemical sensing based on liquid-solid electrification. As a liquid droplet passed across the tribo-negative sensor surface, the induced surface charge balanced with the electrical double layer charge in the liquid droplet. The competition between the double layer charge and surface charge generated characteristic positive and negative voltage spikes, which may serve as a "binary feature" to identify the chemical compound. The sensor showed distinct sensitivity to three amino acids including glycine, lysine and phenylalanine as a function of their concentration. The versatile sensing ability was further demonstrated on several other inorganic and organic chemical compounds dissolved in DI water. This work demonstrated a promising sensing application based on the triboelectrification principle for biofluid sensor development.

6.
Chemistry ; 27(3): 993-1001, 2021 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-32776604

RESUMO

Metal oxalate has become a most promising candidate as an anode material for lithium-ion and sodium-ion batteries. However, capacity decrease owing to the volume expansion of the active material during cycling is a problem. Herein, a rod-like CoC2 O4 ⋅2 H2 O/rGO hybrid is fabricated through a novel multistep solvo/hydrothermal strategy. The structural characteristics of the CoC2 O4 ⋅2 H2 O microrod wrapped using rGO sheets not only inhibit the volume variation of the hybrid electrode during cycling, but also accelerate the transfer of electrons and ions in the 3 D graphene network, thereby improving the electrochemical properties of CoC2 O4 ⋅2 H2 O. The CoC2 O4 ⋅2 H2 O/rGO electrode delivers a specific capacity of 1011.5 mA h g-1 at 0.2 A g-1 after 200 cycles for lithium storage, and a high capacity of 221.1 mA h g-1 at 0.2 A g-1 after 100 cycles for sodium storage. Moreover, the full cell CoC2 O4 ⋅2 H2 O/rGO//LiCoO2 consisting of the CoC2 O4 ⋅2 H2 O/rGO anode and LiCoO2 cathode maintains 138.1 mA h g-1 after 200 cycles at 0.2 A g-1 and has superior long-cycle stability. In addition, in situ Raman spectroscopy and in situ and ex situ X-ray diffraction techniques provide a unique opportunity to understand fully the reaction mechanism of CoC2 O4 ⋅2 H2 O/rGO. This work also gives a new perspective and solid research basis for the application of metal oxalate materials in high-performance lithium-ion and sodium-ion batteries.

7.
J Colloid Interface Sci ; 582(Pt A): 236-245, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32823125

RESUMO

To obtain MOFs materials with good electrochemical performance in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), a kind of hollow urchins Co-MOF with doping fluorine (F) was in-situ assembled on reduced graphene oxide (rGO) using a simple solvothermal reaction. According to XRD, XPS and EDS mapping analysis, the molecular structure should be Co2[Fx(OH)1-x]2(C8O4H4) (denoted as F-Co-MOF). When the composite material is used as active material to assemble LIBs, it not only presents the outstanding reversible capacity (1202.0 mA h g-1 at 0.1 A g-1), but also gives the excellent rate performance and cycle performance (771.5 mA h g-1 at 2 A g-1 after 550 repeated cycles). The remarkable lithium storage capacity of F-Co-MOF/rGO is also reflected in the full cell, where it can still maintain a high capacity of 165.2 mA h g-1 after 300 cycles at 0.2 A g-1. It benefits from the synergistic effect of F-Co-MOF and high conductive rGO networks, so that the reversibility of lithium and sodium storage can be improved. This kind of F doped solvothermal synthesis of MOFs is of great significance for the exploration of high performance materials.

8.
Mol Brain ; 13(1): 147, 2020 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-33183323

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline with accumulation of amyloid beta (Aß) and neurofibrillary tangles that usually begins 15-30 years before clinical diagnosis. Rodent models that recapitulate aggressive Aß and/or the pathology of neurofibrillary tangles are essential for AD research. Accordingly, non-invasive early detection systems in these animal models are required to evaluate the phenotypic changes, elucidate the mechanism of disease progression, and facilitate development of novel therapeutic approaches. Although many behavioral tests efficiently reveal cognitive impairments at the later stage of the disease in AD models, it has been challenging to detect such impairments at the early stage. To address this issue, we subjected 4-6-month-old male AppNL-G-F/NL-G-F knock-in (App-KI) mice to touchscreen-based location discrimination (LD), different object-location paired-associate learning (dPAL), and reversal learning tests, and compared the results with those of the classical Morris water maze test. These tests are mainly dependent on the brain regions prone to Aß accumulation at the earliest stages of the disease. At 4-6 months, considered to represent the early stage of disease when mice exhibit initial deposition of Aß and slight gliosis, the classical Morris water maze test revealed no difference between groups, whereas touchscreen-based LD and dPAL tasks revealed significant impairments in task performance. Our report is the first to confirm that a systematic touchscreen-based behavioral test battery can sensitively detect the early stage of cognitive decline in an AD-linked App-KI mouse model. This system could be applied in future translational research.

9.
ACS Appl Mater Interfaces ; 12(23): 26399-26404, 2020 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-32427459

RESUMO

Cellulosic materials are attractive candidates for nature piezoelectrics. Vertically aligned cellulose nanocrystal (CNC) films are expected to show strong piezoelectricity as the largest dipole moment in CNCs exists along the cellulose chain. In this work, we adapted the confinement cell technology that was used to fabricate colloidal opal structures to align CNC rods vertically on a large scale. The high interfacial energy between the CNC-poly(tetrafluoroethylene) (PTFE) surface and torque induced by the shear force led to a large degree to the vertical alignment of CNC rods. An external DC electric field was added to further align the dipole moment of each CNC to the same direction. The as-obtained CNC film displayed excellent piezoelectric performance, and the piezoelectric coefficient was found to be 19.3 ± 2.9 pm/V, comparable to the piezoelectric coefficient d33 of poly(vinylidene difluoride) (PVDF) (20-30 pm/V). This work presents a new class of high-performance piezoelectric polymeric materials from renewable and biocompatible natural resources.

10.
Adv Funct Mater ; 30(39)2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-33679279

RESUMO

Treating vascular grafts failure requires complex surgery procedures and is associated with high risks. A real-time monitoring vascular system enables quick and reliable identification of complications and initiates safer treatments early. Here, an electric fieldassisted 3D printing technology is developed to fabricate in situ-poled ferroelectric artificial arteries that offer battery-free real-time blood pressure sensing and occlusion monitoring capability. The functional artery architecture is made possible by the development of a ferroelectric biocomposite which can be quickly polarized during printing and reshaped into devised objects. The synergistic effect from the potassium sodium niobite particles and the polyvinylidene fluoride polymer matrix yields a superb piezoelectric performance (bulk-scale d 33 > 12 pC N-1). The sinusoidal architecture brings the mechanical modulus close to the level of blood vessels. The desired piezoelectric and mechanical properties of the artificial artery provide an excellent sensitivity to pressure change (0.306 mV mmHg-1, R 2 > 0.99) within the range of human blood pressure (11.25-225.00 mmHg). The high pressure sensitivity and the ability to detect subtle vessel motion pattern change enable early detection of partial occlusion (e.g., thrombosis), allowing for preventing grafts failure. This work demonstrates a promising strategy of incorporating multifunctionality to artificial biological systems for smart healthcare systems.

11.
Nanomicro Lett ; 12(1): 49, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-34138270

RESUMO

Electrochemical catalysts for oxygen evolution reaction are a critical component for many renewable energy applications. To improve their catalytic kinetics and mass activity are essential for sustainable industrial applications. Here, we report a rare-earth metal-based oxide electrocatalyst comprised of ultrathin amorphous La2O3 nanosheets hybridized with uniform La2O3 nanoparticles (La2O3@NP-NS). Significantly improved OER performance is observed from the nanosheets with a nanometer-scale thickness. The as-synthesized 2.27-nm La2O3@NP-NS exhibits excellent catalytic kinetics with an overpotential of 310 mV at 10 mA cm-2, a small Tafel slope of 43.1 mV dec-1, and electrochemical impedance of 38 Ω. More importantly, due to the ultrasmall thickness, its mass activity, and turnover frequency reach as high as 6666.7 A g-1 and 5.79 s-1, respectively, at an overpotential of 310 mV. Such a high mass activity is more than three orders of magnitude higher than benchmark OER electrocatalysts, such as IrO2 and RuO2. This work presents a sustainable approach toward the development of highly efficient electrocatalysts with largely reduced mass loading of precious elements.

13.
Nanoscale ; 11(44): 21180-21187, 2019 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-31663563

RESUMO

Open porous 3D architectures with Co2(OH)2CO3 nanowires wrapped by highly conductive reduced graphene oxide films are designed and exploited for the first time as anodes for lithium ion batteries; the materials were fabricated via one-step hydrothermal synthesis and self-assembly based on the electrostatic interaction and coordination principle and delivered superior rate performance (1510 and 445 mA h g-1 at 0.1 and 20 A g-1, respectively) and long cycle stability (5000th reversible capacity of 550 mA h g-1 at 10 A g-1). This extremely encouraging result is attributed to the open porous 3D networks and ultrafine diameters of the nanowires, which achieved better electrical contact between the active materials and shortened the ion/electron transport paths; this highlights the synergistic effect of combining the Co2(OH)2CO3 nanowires and rGO films. Especially, the hydroxide (LiOH) can provide a good skeleton structure, ionic conductivity and fast kinetics. Additionally, the lithium storage mechanism of the Co2(OH)2CO3/rGO electrode has been elaborately studied. This work not only enlightens the design of open porous 3D architecture hybrid anode materials of transition-metal hydroxyl carbonates with great potential prospective applications for high energy lithium storage, but also provides a new strategy to construct graphene-based composite materials via the coordination principle and molecular self-assembly theory to achieve more functional materials.

15.
ACS Appl Mater Interfaces ; 10(34): 28679-28685, 2018 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-30085642

RESUMO

Hierarchical CoFe2O4 (CFO) hollow spheres were successfully synthesized via solvothermal method and calcination treatment. The obtained CFO completely inherited the hollow structure and spherical morphology of its precursor of cobalt-based ferrocenyl coordination polymers (Co-Fc-CPs). The three-dimensional (3D) porous hierarchical hollow structure can not only promote the permeation of electrolyte and shorten the lithium-ion transfer distance but also provide a cushion for the volume change during insertion/extraction of lithium ions. To improve the electrochemical properties, the CFO was combined with two forms of carbonaceous materials to controllably obtain 3D CoFe2O4@C (CFO@C) and CoFe2O4@reduced graphene oxide (CFO@rGO) composites. Compared with bare CFO and CFO@C, CFO@rGO exhibited a superior electrochemical performance, achieving a high specific capacity of 933.1 mA h g-1 at a current density of 100 mA g-1 after 100 cycles and showing an outstanding cycling life with a capacity of 615.6 mA h g-1 at 1000 mA g-1 after 600 cycles. In situ X-ray diffraction technique was applied to investigate the lithium storage mechanism during discharge/charge processes. This work provides a new approach to prepare hierarchical hollow bimetallic oxides composites for lithium-ion anode materials.

16.
Nanotechnology ; 29(19): 195401, 2018 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-29457779

RESUMO

Ultrafine ZnSnO3 nanoparticles, with an average diameter of 45 nm, homogeneously grown on reduced graphene oxide (rGO) have been successfully fabricated via methods of low temperature coprecipitation, colloid electrostatic self-assembly, and hydrothermal treatment. The uniformly distributed ZnSnO3 nanocrystals could inhibit the restacking of rGO sheets. In turn, the existence of rGO could hinder the growth and aggregation of ZnSnO3 nanoparticles in the synthesis process, increase the conductivity of the composite, and buffer the volume expansion of the ZnSnO3 nanocrystals upon lithium ion insertion and extraction. The obtained ZnSnO3/rGO exhibited superior cycling stability with a discharge/charge capacity of 718/696 mA h g-1 after 100 cycles at a current density of 0.1 A g-1.

17.
Chem Sci ; 9(46): 8682-8691, 2018 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-30651965

RESUMO

Rechargeable lithium-ion batteries (LIBs) have been the dominating technology for electric vehicles (EV) and grid storage in the current era, but they are still extensively demanded to further improve energy density, power density, and cycle life. Herein, a novel 3D layered nanoarchitecture network of Ni(HCO3)2/rGO composites with highly uniform Ni(HCO3)2 nanocubes (average diameter of 100 ± 20 nm) wrapped in rGO films is facilely fabricated by a one-step hydrothermal self-assembly process based on the electrostatic interaction and coordination principle. Benefiting from the synergistic effects, the Ni(HCO3)2/rGO electrode delivers an ultrahigh capacity (2450 mA h g-1 at 0.1 A g-1), ultrafast rate capability and ultralong cycling stability (1535 mA h g-1 for the 1000th cycle at 5 A g-1, 803 mA h g-1 for the 2000th cycle at 10 A g-1). The detailed electrochemical reaction mechanism investigated by in situ XRD further indicates that the 3D architecture of Ni(HCO3)2/rGO not only provides a good conductivity network and has a confinement effect on the rGO films, but also benefits from the reversible transfer from LiHCO3 to Li x C2 (x = 0-2), further oxidation of nickel, and the formation of a stable/durable solid electrolyte interface (SEI) film (LiF and LiOH), which are responsible for the excellent storage performance of the Li-ions. This work could shed light on the design of high-capacity and low-cost anode materials for high energy storage in LIBs to meet the critical demands of EV and mobile information technology devices.

18.
ACS Appl Mater Interfaces ; 9(40): 34954-34960, 2017 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-28926229

RESUMO

Herein, NixFe1-xOOH/NiFe/NixFe1-xOOH sandwich-structured nanotube arrays (SNTAs) supported on carbon fiber cloth (CFC) (NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC) have been developed as flexible high-performance oxygen evolution reaction (OER) catalysts by a facile in situ electrochemical oxidation of NiFe metallic alloy nanotube arrays during oxygen evolution process. Benefiting from the advantages of high conductivity, hollow nanotube array, and porous structure, NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC exhibited a low overpotential of ∼220 mV at the current density of 10 mA cm-2 and a small Tafel slope of 57 mV dec-1 in alkaline solution, both of which are smaller than those of most OER electrocatalysts. Furthermore, NixFe1-xOOH/NiFe/NixFe1-xOOH SNTAs-CFC exhibits excellent stability at 100 mA cm-2 for more than 30 h. It is believed that the present work can provide a valuable route for the design and synthesis of inexpensive and efficient OER electrocatalysts.

19.
Angew Chem Int Ed Engl ; 56(11): 2960-2964, 2017 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-28140498

RESUMO

TiO2 Co nanotubes decorated with nanodots (TiO2 NDs/Co NSNTs-CFs) are reported as high-performance earth-abundant electrocatalysts for the hydrogen evolution reaction (HER) in alkaline solution. TiO2 NDs/Co NSNTs can promote water adsorption and optimize the free energy of hydrogen adsorption. More importantly, the absorbed water can be easily activated in the presence of the TiO2 -Co hybrid structure. These advantages will significantly promote HER. TiO2 NDs/Co NSNTs-CFs as electrocatalysts show a high catalytic performance towards HER in alkaline solution. This study will open up a new avenue for designing and fabricating low-cost high-performance HER catalysts.

20.
Angew Chem Int Ed Engl ; 55(11): 3694-8, 2016 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-26879125

RESUMO

Herein, we developed FeOOH/Co/FeOOH hybrid nanotube arrays (HNTAs) supported on Ni foams for oxygen evolution reaction (OER). The inner Co metal cores serve as highly conductive layers to provide reliable electronic transmission, and can overcome the poor electrical conductivity of FeOOH efficiently. DFT calculations demonstrate the strong electronic interactions between Co and FeOOH in the FeOOH/Co/FeOOH HNTAs, and the hybrid structure can lower the energy barriers of intermediates and thus promote the catalytic reactions. The FeOOH/Co/FeOOH HNTAs exhibit high electrocatalytic performance for OER, such as low onset potential, small Tafel slope, and excellent long-term durability, and they are promising electrocatalysts for OER in alkaline solution.

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