Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Resultados 1 - 20 de 21
Filtrar
Más filtros

Banco de datos
Tipo del documento
Publication year range
1.
Small ; 16(35): e2000929, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-32762034

RESUMEN

Rechargeable aqueous Zn-ion batteries are promising candidates for large-scale energy storage systems. However, there are many unresolved problems in commercial Zn foils such as dendrite growth and structural collapse. Herein, Cu mesh modified with CuO nanowires is constructed to simultaneously coordinate the ion distribution and electric field during Zn nucleation and growth. Owing to the improved uniformity of Zn plating and the confined Zn growth in the 3D framework, the prepared Zn anodes can be operated steadily in symmetrical cells for 340 h with a low voltage hysteresis (20 mV). This work can provide a new strategy to design the dendrite-free Zn anodes for practical application.

2.
Small ; 15(10): e1804958, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30714342

RESUMEN

Lithium-oxygen (Li-O2 ) batteries are attracting more attention owing to their superior theoretical energy density compared to conventional Li-ion battery systems. With regards to the catalytically electrochemical reaction on a cathode, the electrocatalyst plays a key role in determining the performance of Li-O2 batteries. Herein, a new 3D hollow α-MnO2 framework (3D α-MnO2 ) with porous wall assembled by hierarchical α-MnO2 nanowires is prepared by a template-induced hydrothermal reaction and subsequent annealing treatment. Such a distinctive structure provides some essential properties for Li-O2 batteries including the intrinsic high catalytic activity of α-MnO2 , more catalytic active sites of hierarchical α-MnO2 nanowires on 3D framework, continuous hollow network and rich porosity for the storage of discharge product aggregations, and oxygen diffusion. As a consequence, 3D α-MnO2 achieves a high specific capacity of 8583 mA h g-1 at a current density of 100 mA g-1 , a superior rate capacity of 6311 mA h g-1 at 300 mA g-1 , and a very good cycling stability of 170 cycles at a current density of 200 mA g-1 with a fixed capacity of 1000 mA h g-1 . Importantly, the presented design strategy of 3D hollow framework in this work could be extended to other catalytic cathode design for Li-O2 batteries.

3.
J Colloid Interface Sci ; 676: 80-88, 2024 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-39018813

RESUMEN

Lithium metal is highly favored as an ideal anode material in future high-capacity lithium batteries due to its appealing properties. Nevertheless, the implementation of lithium metal batteries (LMBs) is severely plagued by challenges such as instable solid electrolyte interface (SEI), uncontrolled growth of dendrite, and severe volume expansion. Herein, to address the aforementioned issues, an artificial SEI layer is fabricated, which is comprised of LixSi alloy and Li3N. The in-situ generated LixSi/Li3N interface is formed on the carbon fiber (denoted as CF/LixSi/Li3N) through a spontaneous reaction between molten Li and Si3N4. Density functional theory (DFT) calculations reveal that LixSi alloy has low ion diffusion energy barrier, which facilitates the low nucleation overpotential of Li+ and enables homogeneous lithium deposition. Li3N can further promote the rapid Li+ transport due to the excellent Li+ conductivity. In addition, the reserved 3D space effectively mitigates the volume change along cycling procedure. Owing to the synergistic effect of the LixSi/Li3N protective layer and the 3D structure, the composite anode shows higher cycling stability with a lifetime of more than 3000 cycles at 1 mA cm-2. Furthermore, matched with commercial LiFePO4 (LFP) and LiNi5Co2Mn3O2 (NCM523) cathodes, the full cells also exhibit impressive electrochemical properties. This work introduces an ingenious approach for constructing stable lithium metal anodes and effective lithium metal batteries.

4.
Adv Mater ; 36(39): e2406058, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39097944

RESUMEN

3D substrate with abundant sodiophilic active sites holds promise for implementing dendrite-free sodium metal anodes and high-performance sodium batteries. However, the heightened electrode/electrolyte side reactions stemming from high specific surface area still hinder electrode structure stability and cycling reversibility, particularly under high current densities. Herein, the solid electrolyte interface (SEI) component is regulated and detrimental side reactions are restrained through the uniform loading of Na-Sn alloy onto a porous 3D nanofiber framework (NaSn-PCNF). The strong interaction between Na-Sn alloy and PF6 - anions facilitates the dissociation of sodium salts and releases more free sodium ions for effective charge transfer. Simultaneously, the modulations of the interfacial electrolyte solvation structure and the construction of a high NaF content SEI layer stabilize the electrode/electrolyte interface. NaSn-PCNF symmetrical battery demonstrates stable cycling for over 600 h with an ultralow overpotential of 24.5 mV under harsh condition of 10 mA cm-2 and 10 mAh cm-2. Moreover, the full cells and pouch cells exhibit accelerated reaction kinetics and splendid capacity retention, providing valuable insights into the development of advanced Na substrates for high-energy sodium metal batteries.

5.
Water Res ; 234: 119830, 2023 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-36889086

RESUMEN

Bacterial quorum quenching (QQ) is an effective strategy for controlling biofouling in membrane bioreactor (MBR) by interfering the releasing and degradation of signal molecules during quorum sensing (QS) process. However, due to the framework feature of QQ media, the maintenance of QQ activity and the restriction of mass transfer threshold, it has been difficult to design a more stable and better performing structure in a long period of time. In this research, electrospun fiber coated hydrogel QQ beads (QQ-ECHB) were fabricated by using electrospun nanofiber coated hydrogel to strengthen layers of QQ carriers for the first time. The robust porous PVDF 3D nanofiber membrane was coated on the surface of millimeter-scale QQ hydrogel beads. Biocompatible hydrogel entrapping quorum quenching bacteria (sp.BH4) was employed as the core of the QQ-ECHB. In MBR with the addition of QQ-ECHB, the time to reach transmembrane pressure (TMP) of 40 kPa was 4 times longer than conventional MBR. The robust coating and porous microstructure of QQ-ECHB contributed to keeping a lasting QQ activity and stable physical washing effect at a very low dosage (10g beads/5L MBR). Physical stability and environmental-tolerance tests also verified that the carrier can maintain the structural strength and keep the core bacteria stable when suffering long-term cyclic compression and great fluctuations in sewage quality.


Asunto(s)
Incrustaciones Biológicas , Percepción de Quorum , Incrustaciones Biológicas/prevención & control , Membranas Artificiales , Aguas del Alcantarillado/microbiología , Bacterias/metabolismo , Reactores Biológicos/microbiología
6.
ChemSusChem ; 16(22): e202300505, 2023 Nov 22.
Artículo en Inglés | MEDLINE | ID: mdl-37188641

RESUMEN

Electroreduction of nitrite (NO2 - ) to ammonia (NH3 ) provides a sustainable approach to yield NH3 , whilst eliminating NO2 - contaminants. In this study, Ni nanoparticles strutted 3D honeycomb-like porous carbon framework (Ni@HPCF) is fabricated as a high-efficiency electrocatalyst for selective reduction of NO2 - to NH3 . In 0.1 M NaOH with NO2 - , such Ni@HPCF electrode obtains a significant NH3 yield of 12.04 mg h-1 mgcat. -1 and a Faradaic efficiency of 95.1 %. Furthermore, it exhibits good long-term electrolysis stability.

7.
Materials (Basel) ; 16(8)2023 Apr 19.
Artículo en Inglés | MEDLINE | ID: mdl-37110052

RESUMEN

Extensive research has been conducted on the development of high-rate and cyclic stability anodes for lithium batteries (LIBs) due to their high energy density. Molybdenum disulfide (MoS2) with layered structure has garnered significant interest due to its exceptional theoretic Li+ storage behavior as anodes (670 mA h g-1). However, achieving a high rate and long cyclic life of anode materials remains a challenge. Herein, we designed and synthesized a free-standing carbon nanotubes-graphene (CGF) foam, then presented a facile strategy to fabricate the MoS2-coated CGF self-assembly anodes with different MoS2 distributions. Such binder-free electrode possesses the advantages of both MoS2 and graphene-based materials. Through rational regulation of the ratio of MoS2, the MoS2-coated CGF with uniformly distributed MoS2 exhibits a nano pinecone-squama-like structure that can accommodate the large volume change during the cycle process, thereby significantly enhancing the cycling stability (417 mA h g-1 after 1000 cycles), ideal rate performance, and high pseudocapacitive behavior (with a 76.6% contribution at 1 mV s-1). Such a neat nano-pinecone structure can effectively coordinate MoS2 and carbon framework, providing valuable insights for the construction of advanced anode materials.

8.
Chem Asian J ; 17(24): e202200929, 2022 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-36210332

RESUMEN

Hybrid composite electrolytes incorporate polymer matrixes and garnet filler attract the focus of concern for all-solid-state batteries, which possess high ionic conductivity, superior electrochemical stability, and wide electrochemical window of ceramic electrolyte advantages, and exhibit excellent flexibility and tensile shear strength from polymer electrolyte benefits. Hence, the unique structure design of solid-state electrolytes resolves the existing defects that the use of either single garnet or polymer electrolytes implemented into battery devices. This review summarizes Li7 La3 Zr2 O12 (LLZO)/polymer solid composite electrolytes (SCEs), comprising LLZO/polymer SCEs with various structures and different ratios of LLZO fillers, LLZO/polymer with different kinds of polymers matrix and hybrid lithium-salt, and Li+ transport pathways within the LLZO/polymers SCEs interface. The purpose here is to propose the viewpoints and challenges of LLZO/polymer SCEs to promote the development of next-generation solid electrolytes.

9.
Sci Total Environ ; 810: 151720, 2022 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-34861307

RESUMEN

Carbon dioxide emissions and their sharply rising effect on global warming have encouraged research efforts to develop efficient technologies and materials for CO2 capture. Post-combustion CO2 capture by adsorption using solid materials is considered an attractive technology to achieve this goal. Templated materials, such as Zeolite Templated-Carbons and MOF-Derived Carbons, are considered as the next-generation carbon adsorbent materials, owing to their outstanding textural properties (high surface areas of ca. 4000 m2 g-1 and micropore volumes of ca. 1.7 cm3 g-1) and their versatility for surface functionalization. These materials have demonstrated remarkable CO2 adsorption capacities and CO2/N2 selectivities up to ca. 5 mmol g-1 and 100, respectively, at 298 K and 1 bar, and low isosteric heat of adsorption at zero coverage of ca. 12 kJ mol-1. Herein, a review of the advances in preparation of ZTCs and MDCs for CO2 capture is presented, followed by a critical analysis of the effects of textural properties and surface functionality on CO2 adsorption, including CO2 uptake, CO2/N2 selectivity, and isosteric heat of adsorption. This analysis led to the introduction of a Vmicrox N-content factor to evaluate the interplay between N-content and textural properties to maximize the CO2 uptake. Despite their promising performance in CO2 uptake, further testing using mixtures and impurities, and studies on adsorbent regeneration, and cyclic operation are desirable to demonstrate the stability of the MDCs and ZTCs for large scale processes. In addition, advances in scale-up syntheses and their economics are needed.


Asunto(s)
Dióxido de Carbono , Calentamiento Global , Adsorción
10.
Artículo en Inglés | MEDLINE | ID: mdl-35822804

RESUMEN

Lithium (Li) metal is one of the most promising anode materials for the next-generation batteries, which owns superior specific capacity and energy density. Unfortunately, lithium dendrites that is formed during the charging/discharging process tends to induce capacity degradation and thus short lifespan. In this study, the vanadium oxide (V2O5) and nitrogen-doped vanadium oxide (N-V2O3, N-VO0.9)-modified three-dimensional (3D) reduced graphene oxide ((N)-VOx@rGO) with tunable electronic properties are demonstrated to enable the dendrite-free Li deposition. The soft lithiophilic rGO as the scaffold can provide sufficient void space for Li storage. Meanwhile, the rigid (N)-VOx uniformly anchored on rGO can perfectly maintain the 3D structure, which is crucial for Li to enter the inner space of the 3D framework. Consequently, the (N)-VOx@rGO electrodes achieve dendrite-free electrodeposition under the multifarious deposition capacity and current densities. Compared with the bare lithium electrodes, the asymmetrical cells of (N)-VOx@rGO anode can cycle stably up to 400 h at 2 mA cm-2 current density, together with a low nucleation overpotential of ∼20 mV.

11.
ACS Appl Mater Interfaces ; 14(14): 16394-16403, 2022 Apr 13.
Artículo en Inglés | MEDLINE | ID: mdl-35363460

RESUMEN

Although tremendous efforts have been dedicated to promote the electrochemical stability of sodium metal batteries (SMBs), the uncontrollable dendrites growth and inevitable side reactions at the sodium (Na) anode/electrolyte interface have not been effectively resolved. In this work, a flexible and functionalized 3D framework with mesoporous SnO2 nanosheet arrays (SnO2@CC-12) is fabricated to serve as a sodiophilic matrix toward dendrite-free Na metal anode. The mesoporous SnO2 nanosheet arrays provide abundant sodiophilic sites and sufficient internal voids, which can not only accelerate electron transport to reduce the local current density of Na anode surface but also manipulate the Na+ flux deposition to suppress the growth of Na dendrites. Therefore, the SnO2@CC-12-Na symmetric cell exhibits an ultralow overpotential of 9 mV and superior Na plating/stripping stability over 2200 h at 1.0 mA cm-2. Moreover, the full cells using Na3V2(PO4)3 cathode show favorable high-rate performance and impressive long cycling stability with 95.1% capacity retention over 1000 cycles at 500 mA g-1. This work may provide a new insight into the design of functionalized interface layer with high sodiophilicity toward dendrite-free SMBs.

12.
Bioact Mater ; 17: 261-275, 2022 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-35386455

RESUMEN

One of the pivotal factors that limit the clinical translation of tissue engineering is the inability to create large volume and complex three-dimensional (3D) tissues, mainly due to the lack of long-range mass transport with many current scaffolds. Here we present a simple yet robust sacrificial strategy to create hierarchical and perfusable microchannel networks within versatile scaffolds via the combination of embedded 3D printing (EB3DP), tunable polyelectrolyte complexes (PEC), and casting methods. The sacrificial templates of PEC filaments (diameter from 120 to 500 µm) with arbitrary 3D configurations were fabricated by EB3DP and then incorporated into various castable matrices (e.g., hydrogels, organic solutions, meltable polymers, etc.). Rapid dissolution of PEC templates within a 2.00 M potassium bromide aqueous solution led to the high fidelity formation of interconnected channels for free mass exchange. The efficacy of such channeled scaffolds for in vitro tissue formation was demonstrated with mouse fibroblasts, showing continuous cell proliferation and ECM deposition. Subcutaneous implantation of channeled silk fibroin (SF) scaffolds with a porosity of 76% could lead to tissue ingrowth as high as 53% in contrast to 5% for those non-channeled controls after 4 weeks. Both histological and immunofluorescence analyses demonstrated that such channeled scaffolds promoted cellularization, vascularization, and host integration along with immunoregulation.

13.
ACS Appl Mater Interfaces ; 14(15): 17911-17919, 2022 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-35385267

RESUMEN

Hydrogen (H2) as a high-energy-density carrier is of great potential in the upcoming hydrogen economy. Nevertheless, H2/air mixtures are explosive at H2 concentrations above 4 v/v % and reliable and wide-concentration-range H2 sensors are thus highly desired. Here, hydrogen sensing has been developed using palladium nanoparticles of ∼11.2 nm in diameter chemically decorated on the carbon/nitrogen three-dimensional porous framework of 308 m2 g-1 in specific surface area (Pd NPs@CN 3D framework). Theoretically, the Pd NPs and CN 3D framework are used to construct the Mott-Schottky heterojunctions, in which the CN 3D framework possesses a higher work function, promoting electron transfer to Pd NPs and therefore highly active dissociation of H2. Beneficially, the Pd NPs@CN 3D framework exhibits a wide concentration range of 200 ppm (S ≈ 0.2% and Tres ≈ 15 s) to 40 v/v % (S ≈ 73.8% and Tres ≈ 9 s) H2 sensing at room temperature. Remarkably, the H2 sensor prototype built with the Pd NPs@CN 3D framework shows excellent long-term stability that maintains reliable H2 sensing after 142 days. Such stable hydrogen sensing provides an experimental basis for the wide-concentration-range detection of H2 leakage in the future hydrogen economy.

14.
ACS Appl Mater Interfaces ; 14(10): 12323-12330, 2022 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-35234443

RESUMEN

Zinc (Zn) metal is an attractive anode material for aqueous Zn-ion batteries (ZIBs). Three-dimensional (3D) carbon frameworks may serve as lightweight and robust hosts to enable porous Zn electrodes with a long cycle life. However, Zn electrode tests under a low depth of discharge (DOD) and current density often yield unreliable promises. We used 3D Zn electrodes with carbon nanofiber framework (CNF) backbones (Zn@CNF) as model electrodes to reveal how DOD and current density affect their performance. Plasma-treated CNFs provide sufficient surface hydrophilicity and surface area to allow uniform Zn plating/stripping of a thin and uniform Zn coating (5 mAh cm-2). CNFs only take a small weight fraction (17.5-19.7 wt. %) in the composite electrodes. The 3D structure and graphitic surface efficiently suppress dendrite growth. The cycle life of Zn@CNF can reach 843 h under 10% DOD and 0.5 mA cm-2 in symmetric cells. However, high DOD and current density are detrimental to the stability of 3D Zn electrodes. The cycle life drops to 60.75 h under 60% DOD and 4 mA cm-2. Full cells assembled using Zn@CNF as anodes and V2O5 as cathodes with an N/P capacity ratio of 2.4 delivered a capacity of 133.4 mAh g-1 at 0.1 A g-1. The full cells also showed excellent capacity retention of 92.1% after 260 cycles under 0.5 A g-1 with a high average DODZn of 15.5%. Our results suggest that 3D Zn electrodes with CNF backbones are promising anodes for ZIBs. Studying Zn metal electrodes under practical DOD and current density is essential to access their potential accurately.

15.
ACS Sens ; 6(11): 4206-4216, 2021 11 26.
Artículo en Inglés | MEDLINE | ID: mdl-34739214

RESUMEN

Extracellular polymeric substances (EPS) are produced by many microorganisms and play an essential role in physiological systems such as nutrient storage and stress resistance. Besides, EPS show great potential in biomedical and therapeutic applications due to their biocompatibility and biodegradability. In situ noninvasive monitoring of the EPS produced by microorganisms is thus critical but has not yet been achieved. Herein, we developed a novel aggregation-induced emission (AIE) active nanoprobe enabling in situ visualization of the EPS distribution produced by various microorganisms (cyanobacteria, yeast, freshwater, and marine phytoplankton). The synthesized AIE-active nanoprobe displayed excellent specificity and precision for the staining of EPS, as well as strong photostability, showing great advantage in sensing the EPS in living organisms. With the application of this novel probe, the three-dimensional (3D) framework of EPS distribution was visualized under different environmental conditions (temperature, light intensity, nutrition, and pH). The EPS distribution was found to correlate significantly with the metal tolerance and cyanobacterial photosynthesis capability. Collectively, this study proposed an AIE-active nanoprobe for visualizing the EPS distribution and quantifying the EPS thickness/volume, and has significant implications in understanding the physiological functions of microorganisms.


Asunto(s)
Cianobacterias , Matriz Extracelular de Sustancias Poliméricas , Agua Dulce
16.
ACS Nano ; 14(7): 8678-8688, 2020 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-32530269

RESUMEN

Alkali metals are ideal anodes for high-energy-density rechargeable batteries, while seriously hampered by limited cycle life and low areal capacities. To this end, rationally designed frameworks for dendrite-free and volume-changeless alkali-metal deposition at both high current densities and capacities are urgently required. Herein, a general 3D conductive Ti3C2TX MXene-melamine foam (MXene-MF) is demonstrated as an elastic scaffold for dendrite-free, high-areal-capacity alkali anodes (Li, Na, K). Owing to the lithiophilic nature of F-terminated MXene, conductive macroporous network, and excellent mechanical toughness, the constructed MXene-MF synchronously achieves a high current density of 50 mA cm-2 for Li plating, high areal capacity (50 mAh cm-2) with high Coulombic efficiency (99%), and long lifetime (3800 h), surpassing the Li anodes reported recently. Meanwhile, MXene-MF shows flat voltage profiles for 720 h at 10 mA cm-2 for the Na anode and 800 h at 5 mA cm-2 for the K anode, indicative of the wide applicability. Notably, the high current density of 20 mA cm-2 for 20 mAh cm-2 for the Na anode, accompanying good recyclability was rarely achieved before. When coupled with sulfur or Na3V2(PO4)3 cathodes, the assembled MXene-MF alkali (Li, Na)-based full batteries showcase enhanced rate capability and cycling stability, demonstrating the potential of MXene-MF for advanced alkali-metal batteries.

17.
Nanomicro Lett ; 13(1): 4, 2020 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-34138185

RESUMEN

Coaxial fiber-shaped supercapacitors are a promising class of energy storage devices requiring high performance for flexible and miniature electronic devices. Yet, they are still struggling from inferior energy density, which comes from the limited choices in materials and structure used. Here, Zn-doped CuO nanowires were designed as 3D framework for aligned distributing high mass loading of MnO2 nanosheets. Zn could be introduced into the CuO crystal lattice to tune the covalency character and thus improve charge transport. The Zn-CuO@MnO2 as positive electrode obtained superior performance without sacrificing its areal and gravimetric capacitances with the increasing of mass loading of MnO2 due to 3D Zn-CuO framework enabling efficient electron transport. A novel category of free-standing asymmetric coaxial fiber-shaped supercapacitor based on Zn0.11CuO@MnO2 core electrode possesses superior specific capacitance and enhanced cell potential window. This asymmetric coaxial structure provides superior performance including higher capacity and better stability under deformation because of sufficient contact between the electrodes and electrolyte. Based on these advantages, the as-prepared asymmetric coaxial fiber-shaped supercapacitor exhibits a high specific capacitance of 296.6 mF cm-2 and energy density of 133.47 µWh cm-2. In addition, its capacitance retention reaches 76.57% after bending 10,000 times, which demonstrates as-prepared device's excellent flexibility and long-term cycling stability.

18.
ACS Nano ; 14(5): 5618-5627, 2020 May 26.
Artículo en Inglés | MEDLINE | ID: mdl-32310638

RESUMEN

Li metal anode has been considered as the ideal anode for next-generation batteries due to its ultrahigh capacity and lowest electrochemical potential. However, its practical application is still impeded by low Coulombic efficiency, huge volume change, and safety hazards arising from Li dendrite growth. In this work, a three-dimensional (3D) structured highly stable Li metal anode is designed and easily preapred. Benefiting from the in situ reaction between Li metal and AlN, highly Li+ conductive Li3N and lithiophilic LiAl alloy have been simultaneously formed and homogeneously distributed in the framework, in which Li metal is finely dispersed and embedded. The outstanding electron/ion mixed conductivity of Li3N/LiAl and 3D composite structure with enhanced interfacial area significantly improve the electrode kinetics and suppress the volume change on cycling, while a lithiophilic effect of LiAl alloy and uniform distribution of Li ion flux inside the electrode avoid dendritic Li deposition. As a result, the proposed Li metal electrode exhibits exceptional electrochemical reversibility in both carbonate and ether-based electrolytes. Paired with LiFePO4 and sulfurized polyacrylonitrile (S@pPAN) cathodes, the full cells deliver highly stable and long-term cycling performance. Therefore, the proposed strategy to fabricate Li metal anodes could promote the practical application of Li metal batteries.

19.
ACS Nano ; 13(12): 14308-14318, 2019 Dec 24.
Artículo en Inglés | MEDLINE | ID: mdl-31751116

RESUMEN

Li-metal anode is widely acknowledged as the ideal anode for high-energy-density batteries, but seriously hindered by the uncontrollable dendrite growth and infinite volume change. Toward this goal, suitable stable scaffolds for dendrite-free Li anodes with large current density (>5 mA cm-2) and high Li loading (>90%) are highly in demand. Herein, a conductive and lithiophilic three-dimensional (3D) MXene/graphene (MG) framework is demonstrated for a dendrite-free Li-metal anode. Benefiting from its high surface area (259 m2 g-1) and lightweight nature with uniformly dispersed lithiophilic MXene nanosheets as Li nucleation sites, the as-formed 3D MG scaffold showcases an ultrahigh Li content (∼92% of the theoretical capacity), as well as strong capabilities in suppressing the Li-dendrite formation and accommodating the volume changes. Consequently, the MG-based electrode exhibits high Coulombic efficiencies (∼99%) with a record lifespan up to 2700 h and is stable for 230 cycles at an ultrahigh current density of 20 mA cm-2. When coupled with Li4Ti5O12 or sulfur, the MG-Li/Li4Ti5O12 full-cell offers an enhanced capacity of 142 mAh g-1 after 450 cycles, while the MG-Li/sulfur cell delivers an improved rate performance, implying the great potential of this 3D MG framework for building long-lifetime, high-energy-density batteries.

20.
Acta Crystallogr C Struct Chem ; 75(Pt 4): 469-477, 2019 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-30957793

RESUMEN

A new inorganic-organic hybrid based on an aspartate functionalized polyoxomolybdate, [pentaaquacobalt(II)]-µ-aspartate-[γ-octamolybdate]-µ-aspartate-[pentaaquacobalt(II)] tetrahydrate, [Co2(C4H6NO4)2(γ-Mo8O26)(H2O)10]·4H2O (1), has been synthesized under hydrothermal conditions from the reaction of an Evans-Showell-type polyoxometalate, (NH4)6[Co2Mo10H4O38], and L-aspartic acid. The complex exhibits a supramolecular three-dimensional framework structure in the crystal lattice. Compound 1 was structurally characterized by elemental analyses, IR and UV-Vis (diffuse reflectance) spectroscopy and single-crystal X-ray diffraction. In this compound, aspartic acid acts as a bridge between the two Co atoms and the Mo centres, with the -CH2COOH side chain directly linked to the Mo centre in γ-[Mo8O26]4- and the α-carboxylate side chain bound to the Co centre. Commonly, the binding of transition-metal complexes to POMs involves coordination of the metal to a terminal O atom of the POM so that 1, with a bridging ligand between Mo and Co atoms, belongs to a separate class of hybrid materials. While the starting materials are both chiral and one might expect them to form a chiral hybrid, the decomposition of the chiral Evans-Showell-type POM and its conversion to the centrosymmetric γ-octamolybdate POM, plus the presence of two aspartate ligands centrosymmetrically placed on either side of the POM, leads to the formation of an achiral hybrid. We have studied energetically by means of density functional theory (DFT) calculations and using the Bader's `atoms-in-molecules' analysis the electrostatically enhanced hydrogen bonds (EEHBs) observed in the solid state of 1, which are crucial for the formation of one-dimensional supramolecular assemblies.

SELECCIÓN DE REFERENCIAS
Detalles de la búsqueda