Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 47
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Angew Chem Int Ed Engl ; : e202201101, 2022 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-35452169

RESUMO

Antioxidant treatment strategy by scavenging reactive oxygen species (ROS) is a highly effective disease treatment option. Nanozymes with multiple antioxidant activities can cope with the diverse ROS environment. However, lack of design strategies and limitation of negative correlation for nanozymes with multiple antioxidant activities hindered their development. To overcome these difficulties, here we used ZnMn2 O4 as a model to explore the role of Mn valency at the octahedral site via a valence-engineered strategy, and found that its multiple antioxidant activities are positively correlated with the content of Mn4+ . Therefore, through this strategy, a self-cascading antioxidant nanozyme LiMn2 O4 was constructed, and its efficacy was verified at the cellular level and in an inflammatory bowel disease model. This work not only provides guidance for the design of multiple antioxidant nanozymes, but also broadens the biomedical application potential of multiple antioxidant nanozymes.

2.
Adv Mater ; 34(17): e2200181, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35238080

RESUMO

Integrating solid-state electrolyte (SSE) into Li-metal anodes has demonstrated great promise to unleash the high energy density of rechargeable Li-metal batteries. However, fabricating a highly cyclable SSE/Li-metal anode remains a major challenge because the densification of the SSE is usually incompatible with the reactive Li metal. Here, a liquid-metal-derived hybrid solid electrolyte (HSE) is proposed, and a facile transfer technology to construct an artificial HSE on the Li metal is reported. By tuning the wettability of the transfer substrates, electron- and ion-conductive liquid metal is sandwiched between electron-insulating and ion-conductive LiF and oxides to form the HSE. The transfer technology renders the HSE continuous, dense, and uniform. The HSE, having high ion transport, electron shut-off, and mechanical strength, makes the composite anode deliver excellent cyclability for over 4000 h at 0.5 mA cm-2 and 1 mAh cm-2 in a symmetrical cell. When pairing with LiFePO4 and sulfur cathodes, the HSE-coated Li metal dramatically enhances the performance of full cells. Therefore, this work demonstrates that tuning the interfacial wetting properties provides an alternate approach to build a robust solid electrolyte, which enables highly efficient Li-metal anodes.

3.
Nat Commun ; 13(1): 827, 2022 02 11.
Artigo em Inglês | MEDLINE | ID: mdl-35149676

RESUMO

Nanozyme is a collection of nanomaterials with enzyme-like activity but higher environmental tolerance and long-term stability than their natural counterparts. Improving the catalytic activity and expanding the category of nanozymes are prerequisites to complement or even supersede enzymes. However, the development of hydrolytic nanozymes is still challenged by diverse hydrolytic substrates and following complicated mechanisms. Here, two strategies are informed by data to screen and predict catalytic active sites of MOF (metal-organic framework) based hydrolytic nanozymes: (1) to increase the intrinsic activity by finely tuned Lewis acidity of the metal clusters; (2) to improve the density of active sites by shortening the length of ligands. Finally, as-obtained Ce-FMA-MOF-based hydrolytic nanozyme is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds, and even their mixture, biofilms. This work provides a rational methodology to design hydrolytic nanozyme, enriches the diversity of nanozymes, and potentially sheds light on future evolution of enzyme engineering.


Assuntos
Enzimas/química , Enzimas/metabolismo , Nanoestruturas/química , Biofilmes/crescimento & desenvolvimento , Catálise , Domínio Catalítico , Glicosídeo Hidrolases/química , Hidrólise , Íons , Ligantes , Estruturas Metalorgânicas/química , Metais , Monoéster Fosfórico Hidrolases/química
4.
Chem Commun (Camb) ; 58(10): 1561-1564, 2022 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-35014631

RESUMO

Emerging anodes are important for high energy-density lithium-ion batteries. Here, we present a mesostructured FeS2 comprising nanoparticles embedded in a nanoneedle-assembled nanotube to form a novel "caterpillar with eggs" (CWE) structure. The voids alleviated the volumetric change upon charge-discharge; the nanoneedles-assembled shell provided rapid transport pathways for ions and electrons. The FeS2 anode exhibited a high capacity of 805.1 mA h g-1 after 500 cycles at 2 A g-1. When cycling at -10 °C and 45 °C, the anode provided capacities of 754.5 and 744.4 mA h g-1 after 100 cycles at 1 A g-1, respectively. This good electrochemical performance will enable our special design to find broad applications for developing high-performance energy-storage systems.

5.
Adv Sci (Weinh) ; 9(3): e2103517, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34845856

RESUMO

The shuttling behavior and slow conversion kinetics of the intermediate lithium polysulfides are the severe obstacles for the application of lithium-sulfur (Li-S) batteries over a wide temperature range. Here, an engineered lamellar yolk-shell structure of In2 O3 @void@carbon for the Li-S battery cathode is developed for the first time to construct a powerful barrier that effectively inhibits the shuttling of polysulfides. On the basis of the unique nanochannel-containing morphology, the continuous kinetic transformation of sulfur and polysulfides is confined in a stable framework, which is demonstrated by using X-ray nanotomography. The constructed Li-S battery exhibits a high cycling capability over 1000 cycles at 1.0 C with a capacity decay rate as low as 0.038% per cycle, good rate performance, and temperature tolerance at -10, 25, and 50 °C. A nondestructive in situ monitoring method of the interfacial reaction resistance in different cycling stages is proposed, which provides a new analysis perspective for the development of emerging electrochemical energy-storage systems.

6.
ACS Appl Mater Interfaces ; 14(1): 1203-1211, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34928584

RESUMO

Sodium (Na) metal batteries receive increasing attention because of their high energy densities and low costs that are enabled by the abundant Na resources. However, dendritic growth and low efficiency of Na-metal anodes limit the practical applications of Na-metal batteries. Here, we propose a three-dimensionally pillared structure in which carbonized nanoparticles of zeolite imidazolate framework-8 (ZIF-8) are sandwiched between reduced graphene oxide (rGO) sheets (ZIF-8-C@rGO). Such a pillared structure enables two advantages over rGO. First, the sodiation products of ZIF-8 (NaZn13, Na2O, and N-doped carbon) have a strong chemical affinity to Na metal, thereby inducing favorable nucleation of Na metal to guide Na deposition. Second, the pillared structure could facilitate the diffusion of Na ions through rGO sheets and help homogenize the current distribution, leading to a uniform deposition of Na metal. As a result, ZIF-8-C@rGO exhibits a dendrite-free morphology during Na plating/stripping and excellent cycling stability with high Coulombic efficiency of over 99.8% for at least 2000 h. A symmetric cell could maintain more than 4000 h with a stable average overpotential of only 30 mV at a capacity of 1 mA h cm-2. This work demonstrates that the design of a ZIF-pillared structure could combine thermodynamic and kinetic regulating factors to offer an alternative solution to the development of durable Na electrodes for high-performance Na-metal batteries.

7.
Nano Lett ; 22(1): 263-270, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34905368

RESUMO

Nonuniform Li deposition causes dendrites and low Coulombic efficiency (CE), seriously hindering the practical applications of Li metal. Herein, we developed an artificial solid-state interphase (SEI) with planar polycyclic aromatic hydrocarbons (PAHs) on the surface of Li metal anodes by a facile in situ formation technology. The resultant dihydroxyviolanthron (DHV) layers serve as the protective layer to stabilize the SEI. In addition, the oxygen-containing functional groups in the soft and conformal SEI film can regulate the diffusion and transport of Li ions to homogenize the deposition of Li metal. The artificial SEI significantly improves the CEs and shows superior cyclability of over 1000 h at 4 mAh cm-2. The LiFePO4/Li cell (2.8 mAh cm-2) enables a long cyclability for 300 cycles and high CEs of 99.8%. This work offers a new strategy to inhibit Li dendrite growth and enlightens the design on stable SEI for metal anodes.

8.
Chem Commun (Camb) ; 57(98): 13397-13400, 2021 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-34825912

RESUMO

A novel microcapsule composed of Cu9S5 and SnS2 quantum dots (QDs)/carbon nanotubes (CNTs) prepared through a microfluidic approach was developed for a Li-ion battery anode. CNTs enhance the conductivity, while pores in the shell facilitate electrolyte penetration, and void in the microcapsule buffers the volume change. The microcapsule-based anode displayed stable capacity, a Coulombic efficiency of 99.9%, and reversible rate-performance at temperatures of -10 °C and 45 °C, which are significant for developing high-performance energy-storage materials and battery systems.

9.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 38(5): 986-994, 2021 Oct 25.
Artigo em Chinês | MEDLINE | ID: mdl-34713667

RESUMO

Under the current situation of the rapid development of brain-like artificial intelligence and the increasingly complex electromagnetic environment, the most bionic and anti-interference spiking neural network has shown great potential in computing speed, real-time information processing, and spatiotemporal data processing. Spiking neural network is the core part of brain-like artificial intelligence, which realizes brain-like computing by simulating the structure of biological neural network and the way of information transmission. This article first summarizes the advantages and disadvantages of the five models, and analyzes the characteristics of several network topologies. Then, it summarizes the spiking neural network algorithms. The unsupervised learning based on spike timing dependent plasticity (STDP) rules and four types of supervised learning algorithms are analyzed. Finally, the research on brain-like neuromorphic chips at home and abroad are reviewed. This paper aims to provide learning ideas and research directions for new colleagues in the field of spiking neural network.


Assuntos
Inteligência Artificial , Redes Neurais de Computação , Algoritmos , Encéfalo
10.
Small ; 17(41): e2103051, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34510738

RESUMO

Developing emerging materials for high energy-density lithium-sulfur (Li-S) batteries is of great significance to suppress the shuttle effect of polysulfides and to accommodate the volumetric change of sulfur. Here, a novel porous microcapsule system containing a carbon nanotubes/tin dioxide quantum dots/S (CNTs/QDs/S) composite core and a porous shell prepared through a liquid-driven coaxial microfluidic method as Li-S battery cathode is developed. The encapsulated CNTs in the microcapsules provide pathways for electron transport; SnO2 QDs on CNTs immobilize the polysulfides by strong adsorption, which is verified by using density functional theory calculations on binding energies. The porous shell of the microcapsule is beneficial for ion diffusion and electrolyte penetration. The void inside the microcapsule accommodates the volumetric change of sulfur. The Li-S battery based on the porous CNTs/QDs/S microcapsules displays a high capacity of 1025 mAh g-1 after 100 cycles at 0.1 C. When the sulfur loading is 2.03 mg cm-2 , the battery shows a stable cycling life of 700 cycles, a Coulombic efficiency exceeding 99.9%, a recoverable rate-performance during repeated tests, and a good temperature tolerance at both -5 and 45 °C, which indicates a potential for applications at different conditions.

11.
Nanoscale ; 13(37): 15624-15630, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34515284

RESUMO

Currently, non-ideal anodes restricts the development of long-term stable Li-ion batteries. Several currently available high-capacity anode candidates are suffering from a large volumetric change during charge and discharge and non-stable solid interphase formation. Here, we develop a novel nanosphere-confined one-dimensional yolk-shell anode taking iron phosphide (FeP) as a demonstrating case study. Multiple FeP nanospheres are encapsulated inside an FeP nanotube through a magnetic field-assisted and templated approach, forming a nanosphere-in-nanotube yolk-shell (NNYS) structure. After long-term 1000 cycles at 2 A g-1, the NNYS FeP anode shows a good capacity of 560 mA h g-1, and a coulombic efficiency of 99.8%. A recoverable rate-performance is also obtained after three rounds of tests. Furthermore, the capacities and coulombic efficiency remain stable at temperatures of -10 °C and 45 °C, respectively, indicating good potential for use under different conditions.

12.
Nano Lett ; 21(13): 5805-5812, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34128686

RESUMO

Metal-organic frameworks (MOFs) have been proposed as emerging fillers for composite polymer electrolytes (CPEs). However, MOF particles are usually served as passive fillers that yield limited ionic conductivity improvement. Building continuous MOF reinforcements and exploiting their active roles remain challenging. Here we demonstrate the feasibility of engineering fast Li+ conduction within MOF on molecule conception. Two-dimensional Cu(BDC) MOF is selected as an active filler due to its sufficient accessible open metal sites for perchlorate anion anchoring to release free Li+, verified by theoretical calculations and measurements. A novel Cu(BDC)-scaffold-reinforced CPE is developed via in situ growth of MOF, which provides fast Li+ channels inside MOF and continuous Li+ paths along the MOF/polymer interface for high Li+ conductivity (ambient 0.24 mS cm-1) and enables high mechanical strength. Stable cycling is achieved in solid-state Li-NCM811 full cell using the MOF-reinforced CPE. This molecule-basis Li+ conduction strategy brings new ideas for designing advanced CPEs.


Assuntos
Estruturas Metalorgânicas , Eletrólitos , Íons , Lítio , Polímeros
13.
Nanoscale ; 13(16): 7744-7750, 2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33928991

RESUMO

A lithium-sulfur (Li-S) battery is considered a promising next-generation secondary battery owing to its high theoretical capacity and energy density. However, the volume change and poor conductivity of sulfur, and the shuttle effect, restrict its practical applications. Herein, we develop a yolk-shell Fe3O4@S@C nanochain as the Li-S battery cathode in which sulfur is encapsulated between the Fe3O4 core and the carbon shell. After cycling 500 times at 0.2C, the Fe3O4@S@C nanochains exhibit a stable capacity of 625 mA h g-1 and a coulombic efficiency exceeding 99.8%. When measuring at temperatures of -5 and 45 °C, the capacities remain stable, and a well-reversible rate performance under repeated testing for three rounds is also achieved. Furthermore, density functional theory (DFT) calculations show large adsorption energies of Fe3O4 towards polysulfides, indicating the capability of suppressing the shuttle effect during long-term charge and discharge.

14.
Adv Sci (Weinh) ; 8(8): 2004689, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33898202

RESUMO

Self-healing and flexibility are significant for many emerging applications of secondary batteries, which have attracted broad attention. Herein, a self-healing flexible quasi-solid Zn-ion battery composing of flexible all-in-one cathode (VS2 nanosheets growing on carbon cloth) and anode (electrochemically deposited Zn nanowires), and a self-healing hydrogel electrolyte, is presented. The free-standing all-in-one electrodes enable a high capacity and robust structure during flexible transformation of the battery, and the hydrogel electrolyte possesses a good self-healing performance. The presented battery remains as a high retention potential even after healing from being cut into six pieces. When bending at 60°, 90°, and 180°, the battery capacities remain 124, 125, and 114 mAh g-1, respectively, cycling at a current density of 50 mA g-1. Moreover, after cutting and healing twice, the battery still delivers a stable capacity, indicating a potential use of self-healing and wearable electronics.

15.
Adv Sci (Weinh) ; 8(2): 2002298, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33511006

RESUMO

Magnesium batteries have been considered promising candidates for next-generation energy storage systems owing to their high energy density, good safety without dendrite formation, and low cost of magnesium resources. However, high-performance cathodes with stable capacity, good conductivity, and fast ions transport are needed, since many conventional cathodes possess a low performance and poor preparation controllability. Herein, a liquid-driven coaxial flow focusing (LDCFF) approach for preparing a novel microcapsule system with controllable size, high loading, and stable magnesium-storage performance is presented. Taking the MoS2-infilled microcapsule as a case study, the magnesium battery cathode based on the microcapsules displays a capacity of 100 mAh g-1 after 100 cycles. High capacity retention is achieved at both low and high temperatures of -10, ‒5, and 45 °C, and a stable rate-performance is also obtained. The influences of the liquid flow rates on the size and shell thickness of the microcapsules are investigated; and electron and ion diffusion properties are also studied by first-principle calculations. The presented LDCFF method is quite general, and the high performance of the microcapsules enables them to find broad applications for making emerging energy-storage materials and secondary battery systems.

16.
Adv Mater ; 33(3): e2005024, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33283334

RESUMO

While the unique physicochemical properties of nanomaterials that enable regulation of nanozyme activities are demonstrated in many systems, quantitative relationships between the nanomaterials structure and their enzymatic activities remain poorly understood, due to the heterogeneity of compositions and active sites in these nanomaterials. Here, inspired by metalloenzymes with well-defined metal-ligand coordination, a set of substituted metal-organic frameworks (MOFs) with similar coordination is employed to investigate the relationship between structure and oxidase-mimicking activity. Both experimental results and density functional theory calculations reveal a Hammett-type structure-activity linear free energy relationship (H-SALR) of MIL-53(Fe) (MIL = Materials of Institute Lavoisier) nanozymes, in which increasing the Hammett σm value with electron-withdrawing ligands increases the oxidase-mimicking activity. As a result, MIL-53(Fe) NO2 with the strongest electron-withdrawing NO2 substituent shows a tenfold higher activity than the unsubstituted MIL-53(Fe). Furthermore, the generality of H-SALR is demonstrated for a range of substrates, one other metal (Cr), and even one other MOF type (MIL-101). Such biologically inspired quantitative studies demonstrate that it is possible to identify quantitative structure-activity relationships of nanozymes, and to provide detailed insight into the catalytic mechanisms as those in native enzymes, making it possible to use these relationships to develop high-performance nanomaterials.


Assuntos
Materiais Biomiméticos/química , Estruturas Metalorgânicas/química , Oxirredutases/metabolismo , Engenharia de Proteínas
17.
ACS Appl Mater Interfaces ; 12(42): 47590-47598, 2020 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-32991143

RESUMO

The development of a high specific energy lithium-sulfur battery is heavily hindered by the so-called "shuttle effect". Nevertheless, as an effective strategy, most modified separators cannot block and reuse polysulfides simultaneously. Here, a unique and versatile film fabricated by nitrogen and phosphorus co-doped carbon nanofibers uniformly anchored with TiC nanoparticles is incorporated between the separator and cathode of the lithium-sulfur battery. The battery armed with this functional film exhibits a high capacity of 737.1 mA h g-1 at 5 C with a slow capacity-fading rate of 0.06%/cycle over 500 cycles. Even when augmenting the sulfur loading to 17.1 mg cm-2, it can achieve a capacity of 837.3 mA h g-1 with a retention of ∼80% after 50 cycles. The TiC nanoparticles as well as heteroatom doping in the porous carbon nanofiber exhibit strong physiochemical adsorption and catalytic effect, which is proven by experiments and theoretical calculations. Thus, the diffusion of polysulfides can be effectively inhibited. Meanwhile, heteroatom doping can further enhance the conductivity and reaction activity of this film. Hence, the adsorbed polysulfides could be revived and renewed during the subsequent cycling process, which is accurately observed and confirmed by experiments for the first time.

18.
Nanotechnology ; 31(45): 455402, 2020 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-32808597

RESUMO

High-energy-density secondary batteries are required for many applications such as electric vehicles. Lithium-sulfur (Li-S) batteries are receiving broad attention because of their high theoretical energy density. However, the large volume change of sulfur during cycling, poor conductivity, and the shuttle effect of sulfides severely restrict the Li-storage performance of Li-S batteries. Herein, we present a novel core-shell nanocomposite consisting of a sulfur core and a hydrogel polypyrrole (PPy) shell, enabling an ultra-high sulfur content of about 98.4% within the composite, which greatly exceeds many other conventional composites obtained by coating sulfur onto some hosts. In addition, the void inside the core-shell structure effectively accommodates the volume change; the conductive PPy shell improves the conductivity of the composite; and PPy is able to adsorb polysulfides, suppressing the shuttle effect. After cycling for 200 cycles, the prepared S@void@PPy composite retains a stable capacity of 650 mAh g-1, which is higher than the bare sulfur particles. The composite also exhibits a fast Li ion diffusion coefficient. Furthermore, the density functional theory calculations show the PPy shell is able to adsorb polysulfides efficiently, with a large adsorption energy and charge density transfer.

19.
J Colloid Interface Sci ; 579: 823-831, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32679379

RESUMO

Ni-Zn, Zn-MnO2, and Zn-air batteries have the advantages of inflammability, material abundance, and high specific energy. However, their applications are limited by the poor rechargeability of zinc anodes, which are related to shape changes, dendrite growth, corrosion, passivation, dissolution, etc. In this study, we developed a zeolitic-imidazolate framework (ZIF)-based route to construct a novel ZnO/Sb composite anode. The resultant zinc anode is scaffolded on carbon cloth (CC) and then encapsulated by carbonized resorcinol-formaldehyde resins. Such a carbon-framed ZnO/Sb anode shows the excellent rate and cycling properties because Sb suppresses the corrosion and improves interparticle conductivity, and the ZIF-derived carbon frame accommodates the shape changes, blocks the zinc dissolution, and accelerates the charge transfer. This work demonstrates the effectiveness of anti-corrosion and carbon-framed structure design on pouch and cable-like Ni-Zn batteries.

20.
Small ; 16(22): e2000870, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32372530

RESUMO

Lithium-sulfur batteries, as one of promising next-generation energy storage devices, hold great potential to meet the demands of electric vehicles and grids due to their high specific energy. However, the sluggish kinetics and the inevitable "shuttle effect" severely limit the practical application of this technology. Recently, design of composite cathode with effective catalysts has been reported as an essential way to overcome these issues. In this work, oxygen-deficient ferric oxide (Fe2 O3- x ), prepared by lithiothermic reduction, is used as a low-cost and effective cathodic catalyst. By introducing a small amount of Fe2 O3- x into the cathode, the battery can deliver a high capacity of 512 mAh g-1 over 500 cycles at 4 C, with a capacity fade rate of 0.049% per cycle. In addition, a self-supporting porous S@KB/Fe2 O3- x cathode with a high sulfur loading of 12.73 mg cm-2 is prepared by freeze-drying, which can achieve a high areal capacity of 12.24 mAh cm-2 at 0.05 C. Both the calculative and experimental results demonstrate that the Fe2 O3- x has a strong adsorption toward soluble polysulfides and can accelerate their subsequent conversion to insoluble products. As a result, this work provides a low-cost and effective catalyst candidate for the practical application of lithium-sulfur batteries.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...