Meso-macroporous Structure Research Articles

Citric acid steam-assisted decomposition method for the synthesis of meso-macroporous magnesium oxide with rich oxygen defects: Efficient removal and convenient recovery property of Congo red and Ni(II)

The removal of Congo red (CR) and heavy metal ion nickel (Ni(II)) from wastewater is a critical concern for safeguarding the aquatic environment and promoting sustainable development. Herein, a novel citric acid steam-assisted decomposition method is applied to form meso-macroporous magnesium oxide (MgO) with rich oxygen defects. As the gelation process of xerogel precursor could be significantly promoted by the steam-assisted process with citric acid solution as steam source, the morphology structure of MgO changes into loose aggregates with sharp edges and is covered by a layer of MgO nanoparticles. The synthesized MgO, with a high surface area (103.60 m2 g−1), meso-macroporous structure and abundant oxygen defects, exhibits super adsorption capacities for CR (7109.85 mg g−1) and Ni(II) (1405.88 mg g−1). The MgO (0.4 g L−1) could completely remove CR (200 mg L−1) in 30 min, while 10 min for Ni(II) (200 mg L−1) adsorption. The adsorption mechanism of MgO for CR and Ni(II), including electrostatic interaction, oxygen vacancy capture, hydrogen bonding and ion exchange, is effectively enhanced due to the appearance of meso-macroporous structure and oxide defects, such as 5-coordinated oxygen anion (O5C2−) for terrace, 4-coordinated oxygen anion (O4C2−) for edge and 3-coordinated oxygen anion (O3C2−) for corner. The easy calcination is applied to recycle MgO after CR adsorption and the CR removal efficiencies are above 98 % after five cycles. Meanwhile, a nickel chelator (Na2EDTA) and calcination are used to regenerate the MgO after Ni(II) adsorption and the adsorbent shows an insignificant removal efficiency loss after three cycles. The meso-macroporous MgO with rich oxygen defects has the characteristics of high adsorption speed, high adsorption capacity and convenient recovery property, and is expected to become an ideal material for the rapid treatment of high concentration wastewater.

Boosting capacitive deionization of monovalent and hardness ions using Ti3C2Tx MXene as an intercalation-type pseudocapacitive electrode

MXene is a promising electrode material for energy storage and capacitive deionization (CDI) applications. In this study, a viable approach was developed to synthesize Ti3C2Tx at different LiF/Ti3AlC2 mass ratios of 0.5 – 2.0 for the enhanced CDI to remove different cations including hardness (Mg2+ and Ca2+), salt (Na+), and ammonium (NH4+) ions. The Ti3C2Tx was fabricated using the hydrothermal method in the presence of LiF and HCl. The optimal mass ratio of 1.0 results in the formation of hydrophilic and well-delaminated nanosheets. Moreover, the Ti3C2Tx-1 shows an interconnected meso-macroporous structure with a specific surface area of 48.4 m2/g. The Ti3C2Tx MXene exhibits an exceptional electrochemical performance with a specific capacitance of 540 F g−1 at 5 mV s−1 in the presence of 1 M H2SO4. A remarkable desalination performance with the salt adsorption capacity (SAC) of 39.7 mg g−1 is obtained. The well-suited lattice fringe and inter-connected porous structure of the Ti3C2Tx nanosheets accelerate the electron transport, which can maintain the cyclability over 50 cycles. This enhanced electron transport leads to an improved deionization capability during the CDI process. Moreover, the Ti3C2Tx-based CDI device exhibits prominent selectivity for hardness ions with SACs of 43.8 and 39.5 mg g−1 for Ca2+ and Mg2+, respectively. The SAC of NH4+ can also be up of 39.7 mg g−1 at 1000 mg L−1. Results in this study clearly elaborate the promising potentiality for the utilization of MXene as an effective electrode material for desalination and other electrochemical applications.

Synergistic induction of mesoporosity in metal oxide film electrode through electrohydrodynamic splitting of precursor and simultaneous soft templating

Porous metal oxide films are formed over Ni foam using template-assisted electrospray deposition of precursor sol. Pluronic F127, a triblock organic copolymer surfactant as the template source is added to the respective metal acetate sols to prepare Ni and Co oxide films. The unique cubic phases of metal oxides with the meso-macroporous structure provide easier access for electrolyte ions for faradic charge storage. Hollow spherical and honeycomb-like morphologies, respectively in NiO, and Co3O4 film electrodes contributes to the specific capacities (108 mC cm−2 (270 mF cm−2) and 98 mC cm−2 (245 mF cm−2) respectively at 1 mA cm−2). These NiO and Co3O4 film electrodes, when placed with porous carbon films as counter electrode, derived from the electrospray coating of the polymer precursor shows specific energy at the levels of 11.7 Wh kg−1 and 18 Wh kg−1 respectively. The template-assisted electrospray approach reported here can be extended to the fabrication of other oxides, mixed metal oxides, or binary/ternary oxide systems.

The Effect of Hydrothermal, Microwave, and Mechanochemical Treatments of Tin Phosphate on Sorption of Some Cations

The samples of precipitated tin (IV) phosphate, modified using hydrothermal, microwave, and mechanochemical procedures, were studied in the process of Cs(I), Sr(II), and U(VI) ion sorption. The initial and modified samples were investigated before and after sorption using XRD, XRF, FTIR, and nitrogen adsorption–desorption. It was found that the modification procedures transformed the micro-mesoporous structure of the initial sample into a meso–macroporous structure. As a result, the sorption capacity in relation to all ions increases several times. This indicates the determining role of the porous structure, primary content, and mesopore size on the sorption activity of tin phosphate. The samples, treated in the form of a wet gel, which is a novel procedure, showed the maximum sorption indicators. The sorption of all the tested ions is described by the Langmuir isotherm.

Enhancing bioelectrocatalytic oxidation of gaseous chlorobenzene by introducing transmembrane Ru4+/Ru3+-mediated reversible intracellular electron transfer

Microbial electrolysis cell (MEC) is a cost-effective process to eliminate chlorinated volatile organic compounds. Poor mass transfer and sluggish intracellular electron transfer remain obstacles. To overcome these, a Ru-mesoporous TiO2/macroporous carbon (Ru-MeT/MaC) bio-anode was tailored here. The hierarchically meso-macroporous structure separated biofilm formation and chlorobenzene adsorption, improving chlorobenzene mass transfer. Further, modifying Ru created a reversible intracellular electron transfer pathway by introducing transmembrane Ru4+/Ru3+ redox couple within bacteria. Such a unique transmembrane introduction induced a compelling bacteria-electricity synergism accompanied by the acclimation of dual-functional genera (degrader & exoelectrogen), promoting the decomposition of aromatic compounds toward organic acids. Those features enabled the resulting MEC to exhibit a super-prominent chlorobenzene elimination capacity (136.7 g m−3 h−1) with a short empty bed residence time (60 s), superior to those of state-of-the-art bioelectrocatalytic processes reported. Leveraging the reversible electron transfer, the Ru-MeT/MaC bio-anode was operated in the charging-discharging mode to further enhance chlorobenzene removal. SynopsisThe concept of introducing bioavailable conductive redox couple into bacteria via reasonably designing the functional structure of the bio-anode is expected to enhance the bioelectrocatalytic oxidation of hydrophobic Cl-VOCs and therefore alleviate air pollution.

Three-dimensional nitrogen-doped rGO-siloxene nanocomposite anode for Li-ion storage

In this work, we synthesize a 3D nitrogen-doped rGO (NrGO)-siloxene aerogel nanocomposite using a simple and low-cost hydrothermal process and demonstrate its use as an anode material for lithium-ion storage. The meso-macroporous structure of the N-doped rGO (NrGO) aerogel enhances the electrical conductivity and accommodates the volume expansion of siloxene sheets during cycling. Thereby, the NrGO-siloxene (NGSil) composite shows improved kinetics and structural stability resulting in an excellent reversible discharge capacity of 472.07 mA h g−1 at 0.1 A g−1, which is higher than those of the hydrothermally treated siloxene (HT-Sil, 31.59 mA h g−1) and the undoped rGO-siloxene (GSil, 296.33 mA h g−1). Moreover, the NGSil composite exhibits a good rate performance (177 mA h g−1 at 6 A g−1), and excellent long-term cycling stability (243.12 mA h g−1 after 1000 cycles) with a steady coulombic efficiency of 99.5% at 1 A g−1.

Effect of MgO/Al2O3 ratio in the support of mesoporous Ni/MgO–Al2O3 catalysts for CO2 utilization via reverse water gas shift reaction

2 and 5 wt.% nickel was supported on different MgO to Al2O3 (M/A) ratios (0.5, 1 and 1.5) and evaluated in reverse water gas shift (RWGS) reaction. The catalysts were prepared by impregnation method and the nanocrystalline supports were synthesized by simple surfactant (CTAB) assisted precipitation technique. The following catalytic activity was observed for 2% & 5% Ni supported on different M/A ratios; M/A = 1 > M/A = 1.5 > M/A = 0.5. The perceived order was related to difference in the structural properties of supports and catalysts. The BET results revealed decrease of specific surface area with increase in M/A ratio, mesoporous structure for M/A = 0.5 and 1 and meso-macroporous structure for M/A = 1.5. The effect of nickel loading on the support with M/A = 1 was also investigated. 1.5% Ni showed high CO2 conversion of 39.2% at 700 °C and CO selectivity higher than 90% at all temperatures. Increase of nickel loading higher than 1.5% was in favor of CH4 formation. The TEM images of 1.5% Ni on M/A = 1 revealed uniform distribution of Ni particles with average size of 4.9 nm. The H2-TPR analysis displayed shifting of maximum temperature of the main peak (γ) to higher temperatures with increase of M/A ratio in the support, indicating harder reducibility of catalysts with higher MgO content. The 1.5% Ni supported on M/A = 1 (MgAl2O4) showed great catalytic stability and CO selectivity (>98%) after 15 h on stream.

Introducing micropores into carbon nanoparticles synthesized via a solution plasma process by thermal treatment and their charge storage properties in supercapacitors.

Carbon materials synthesized via a solution plasma process (SPP) have recently shown great potential for various applications. However, they mainly possess a meso-macroporous structure with a lack of micropores, which limits their applications for supercapacitors. Herein, carbon nanoparticles (CNPs) were synthesized from benzene via SPP and then subjected to thermal treatment at different temperatures (400, 600, 800, and 1000 °C) in an argon environment. The CNPs exhibited an amorphous phase and were more graphitized at high treatment temperatures. A small content of tungsten carbide particles was also observed, which were encapsulated in CNPs. An increase in treatment temperature led to an increase in the specific surface area of CNPs from 184 to 260 m2 g-1 through the development of micropores, while their meso-macropore structure remained unchanged. The oxygen content of CNPs decreased from 14.72 to 1.20 atom% as the treatment temperature increased due to the degradation of oxygen functionality. The charge storage properties of CNPs were evaluated for supercapacitor applications by electrochemical measurements using a three-electrode system in 1 M H2SO4 electrolyte. The CNPs treated at low temperatures exhibited an electric double layer and pseudocapacitive behavior due to the presence of quinone groups on the carbon surface. With increasing treatment temperature, the electric double layer behavior became more dominant, while pseudocapacitive behavior was suppressed due to the quinone degradation. Regarding cycling stability, the CNPs treated at high temperatures (with a lack of oxygen functionality) were more stable than those treated at low temperatures. This work highlights a way of introducing micropores into CNPs derived from SPP via thermal treatment, which could be helpful for controlling and adjusting their pore structure for supercapacitor applications.

Nitrogen-doped meso-macroporous carbon from waste asphalt as high-performance anode materials for alkali-ion batteries

Rechargeable alkali-ion (Li+, Na+, and K+) batteries with high conversion efficiency have attracted much attention for portable and sizeable energy storage. Deriving valuable battery materials from valueless waste materials is highly desirable to meet the surging demand of energy storage. However, waste-derived carbon materials often show low specific capacity and poor reversibility due to untamed physiochemical properties. In this paper, nitrogen doped meso-macroporous carbon (NMPC) materials are produced from waste asphalt with the assistance of nano-Fe2O3 template and melamine modification. The products show interconnected three-dimensional meso-macroporous structures and tunable nitrogen contents. As an anode material for Li-ion batteries, the NMPC with optimum nitrogen content delivers a reversible capacity of 602.3 mA h g−1 at 0.2 A g−1. Furthermore, it also discharges a reversible capacity of 210.8 mA h g−1 after 200 cycles and 201.5 mA h g−1 after 500 cycles for Na-ion batteries and K-ion batteries, respectively. The excellent and versatile electrochemical properties enable the concept of waste recovery and resource utilization, which can be used for the manufacture of environmentally friendly energy storage systems.

Understanding the effects of electrode meso-macropore structure and solvent polarity on electric double layer capacitors based on a continuum model

The structures of electrode meso-macropore and the solvent polarity are the crucial factors dominating the performance of the electric double layer capacitors (EDLCs), but their impacts are usually tangled and difficult to decouple and quantitate. Here the effects of electrode meso-macropore structure and solvent polarity on the specific capacitance of an EDLC are quantitatively investigated using a steady-state continuum model. The simulation results indicate the specific capacitances are significantly affected by the meso-macropore surface structure. The specific capacitances significantly decrease for both convex surface structures but obviously increase for both concave surface structures, with the increase of curvature radius from 1 to 20 nm. As for solvents, the polar solvent with high saturated dielectric permittivity improves the capacitance performance. Moreover, the electrode meso-macropore structure is of more concern compared with solvent polarity when aiming at enhancing the specific capacitance. These results provide fundamentals for the rational design of porous electrodes and polar electrolytes for EDLCs. © 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd.. All rights reserved.

High-Value Utilization of Silicon Cutting Waste and Excrementum Bombycis to Synthesize Silicon–Carbon Composites as Anode Materials for Li-Ion Batteries

Silicon-based photovoltaic technology is helpful in reducing the cost of power generation; however, it suffers from economic losses and environmental pollution caused by silicon cutting waste. Herein, a hydrothermal method accompanied by heat treatment is proposed to take full advantage of the photovoltaic silicon cutting waste and biomass excrementum bombycis to fabricate flake-like porous Si@C (FP-Si@C) composite anodes for lithium-ion batteries (LIBs). The resulting FP-Si@C composite with a meso-macroporous structure can buffer the severe volume changes and facilitate electrolyte penetration. Meanwhile, the slightly graphitic carbon with high electrical conductivity and mechanical strength tightly surrounds the Si nanoflakes, which not only contributes to the ion/electron transport but also maintains the electrode structural integrity during the repeated lithiation/delithiation process. Accordingly, the synergistic effect of the unique structure of FP-Si@C composite contributes to a high discharge specific capacity of 1322 mAh g−1 at 0.1 A g−1, superior cycle stability with a capacity retention of 70.8% after 100 cycles, and excellent rate performance with a reversible capacity of 406 mAh g−1 at 1.0 A g−1. This work provides an easy and cost-effective approach to achieving the high-value application of photovoltaic silicon cutting waste, as well as obtaining high-performance Si-based anodes for LIBs.

Pore structure heterogeneity of Wufeng-Longmaxi shale, Sichuan Basin, China: Evidence from gas physisorption and multifractal geometries

Understanding the heterogeneity of the nanoscale pore structure is critical for assessment of hydrocarbon flow and storage in porous reservoirs. Multifractal theory is a powerful method to acquire the detailed heterogeneity information of the multiple pore system. The generalized dimension spectrum and singularity spectrum are two forms to depict the multifractal feature. Hurst exponent ( H ) and the width of singularity spectrum ( Δα ) are two parameters to effectively assess the pore connectivity and heterogeneity, respectively. In this study, multifractal analysis was performed on over-mature Wufeng-Longmaxi shales and their corresponding isolated organic matter (OM) via gas physisorption (CO 2 and N 2 ) test to ascertain the pore heterogeneity and its governing factors. Micropore (diameter<2 nm) structure in bulk shale contains stronger pore heterogeneity but weaker connectivity than meso-macropore (diameter = 2–100 nm) structure. The comparison of heterogeneity features of shale versus its isolated OM reveals that micropore associated with minerals could enhance the micropore heterogeneity in bulk shale, while meso-macropore existing in minerals could reduce the meso-macropore heterogeneity in bulk shale. Besides, the total organic carbon content has a positive effect on the micropore heterogeneity. The micropore and meso-macropore volume have a certain impact on the pore heterogeneity in the corresponding pore size ranges. Compared with the low-mature Bakken shale, the over-mature Wufeng-Longmaxi shale contains the stronger micropore heterogeneity but weaker meso-macropore heterogeneity, where less difference between the micropore and meso-macropore heterogeneities was also observed. We deduced that the whole shale pore spectrum likely tends to be homogeneous along with the OM thermal maturation. • Pore structure heterogeneity was quantified based on the multifractal theory. • For over-mature shale, micropore shows stronger heterogeneity but weaker connectivity. • The geological controlling factors of pore heterogeneity were discussed. • Pore heterogeneity for shales with different thermal maturities was compared.

Synergy of macro-meso bimodal pore and Ni-Co alloy for enhanced stability in dry reforming of methane

Dry reforming of methane (DRM) is an ideal reaction to chemically utilize two important greenhouse gases, methane and carbon dioxide, but the serious carbon deposition often makes the catalysts deactivated, which limits its industrialized application of DRM. To improve the catalytic performance and stability of the catalyst, a bimodal pore structure Ni-Co catalyst was prepared and applied for DRM in this work. The fresh and spent samples were characterized by SEM, TEM, XRD, XPS, TPR, TPH, Raman spectra and N2 adsorption–desorption. The results indicated that Ni-Co alloy phases and bimodal meso-macroporous structure were formed in catalysts. The effect of Co/Ni and bimodal structure on catalytic activity and carbon deposition resistance were investigated at 700 °C, W/F = 1 g·h/mol. Results show that the catalyst with bimodal pore structure of cobalt and nickel ratio of 0.5 (NC0.5-M100-MA) exhibited the best catalytic performance after 100 h reaction, the conversion of CH4 and CO2 are 73.1% and 81.6%, respectively, 4.5% and 4.7% higher than that of the Ni-M100-MA, respectively. The amount of carbon deposits has a small increased compared to that of Ni-M100-MA, but it’s stable in whole reaction since most of the carbon deposits are amorphous carbon, which is easy to eliminate. The stability is mainly contributed to the synergy effect of Ni-Co alloy and macro-meso bimodal pore structure, which helps suppress the conversion of amorphous carbon into coke.

Synthesis of a clustered carbon aerogel interconnected by carbon balls from the biomass of taros for construction of a multi-functional electrochemical sensor

In this study, a clustered carbon aerogel interconnected by carbon balls (CCAI-CB) was prepared as an electrode material to construct a multi-functional electrochemical sensor. CCAI-CB derived from taros (Colocasia esculenta (L). Schott) possesses meso-macroporous structure and plenty of defective sites, and shows notable activity in electrocatalysis as an electrode material. We investigated the application of CCAI-CB modified glassy carbon electrode (CCAI-CB/GCE) for determination of ascorbic acid (AA) and hydrogen peroxide (H2O2). Compared with carbon nanotubes (CNTs) modified GCE (CNTs/GCE) and bare GCE, CCAI-CB/GCE shows lower detection limit (0.23 μM for AA and 1.31 μM, S/N = 3), higher sensitivities (220.53, 148.86 or 94.39 μA mM−1 cm−2 for AA and 83.06 or 49.07 μA mM−1 cm−2 for H2O2). Concentrations of AA and H2O2 in real samples were determined at CCAI-CB/GCE with satisfactory detection results obtained. In addition, when the CCAI-CB/GCE was used for electrocatalysis of other biomolecules, it also exhibits high electrochemical activity. Thus, CCAI-CB could be a promising electrode material for the construction of multi-functional electrochemical sensors.

Enhanced Removal of Sulfonated Lignite from Oil Wastewater with Multidimensional MgAl-LDH Nanoparticles.

In this study, hierarchical MgAl-LDH (layered double hydroxide) nanoparticles with a flower-like morphology were prepared under a hydrothermal condition by employing worm-like micelles formed by cetyltrimethylammonium bromide (CTAB) and salicylic acid (SA) as templates. The morphology and structure of the materials were characterized by Brunauer–Emmett–Teller (BET), SEM, and XRD analyses. The performance for the adsorption of sulfonated lignite (SL) was also investigated in detail. FTIR was used to detect the presence of active functional groups and determine whether they play important roles in adsorption. The results showed that the hierarchical MgAl-LDH nanoparticles with a specific surface area of 126.31 m2/g possessed a flower-like morphology and meso–macroporous structures. The adsorption capacity was high—its value was 1014.20 mg/g at a temperature of 298 K and an initial pH = 7, which was higher than traditional MgAl-LDH (86 mg/g). The adsorption process of sulfonated lignite followed the pseudo-second-order kinetics model and conformed to Freundlich isotherm model with a spontaneous exothermic nature. In addition, the hierarchical MgAl-LDH could be regenerated and used, and the adsorption was high after three adsorption cycles. The main adsorption mechanisms were electrostatic attraction and ion exchange between the hierarchical MgAl-LDH and sulfonated lignite.

Sol–gel synthesis of Dictyophora-shaped hierarchically porous Mn2SnO4/C materials as anodes for Li-ion batteries

Dictyophora-shaped porous Mn2SnO4/C composite materials were prepared by a sol–gel process accompanied by phase separation. The samples possess a well-defined interconnected micro–meso–macroporous structure which benefits the cycling performance for Li-ion batteries.

Effects of nano-pore and macromolecule structure of coal samples on energy parameters variation during methane adsorption under different temperature and pressure

Research on methane adsorption in coal reservoirs by combining adsorption energy variation with molecular structure helps to explain the micro adsorption mechanism of methane. According to experimental data obtained from methane isothermal adsorption at different temperatures (20, 30 and 40 degrees centigrade) and pressure (0 ~ 10 MPa), effects of temperature and pressure on the energy parameters (adsorption potential, adsorption space, surface free energy and isosteric heat of adsorption) of middle and high rank coal samples were discussed from the angles of adsorption kinetics and thermodynamics. Moreover, pore and macromolecular structure of all the samples were elucidated by employing low temperature liquid nitrogen, carbon dioxide adsorption and infrared spectroscopy. Then, relationship between micro-pore structure, chemical structure parameters and adsorption energy variation were discussed. The following results has been achieved. 1) As adsorption pressure increases, reduction rate of surface free energy grows rapidly at the early period of lower pressure stage (0 ~ 8 MPa), then it becomes less than that of higher pressure stage (8 ~ 10 MPa). At the same adsorption pressure, reduction value rate of surface free energy decreases as coal rank increase. 2) Increasing temperature causes the decrease of adsorption capacity (VL and PL), and the sensitivity of temperature to adsorption capacity of high rank samples is stronger than that of middle rank samples. As Ro, max increases, initial isosteric heat of adsorption gradually increases. 3) In contrast to meso-macropore, micro-pore is critical affecting adsorption capacity. Larger specific surface area and adsorption potential of micro-pore results in a decrease in the surface free energy. 4) When Ro, max is less than 2.5%, the graphitization degree of aromatic increase linearly, and the length of the aliphatic chain reaches the minimum value. After that, macromolecule parameters varies smoothly. Then, functional groups variation affects the micro-pore structure evolution, whereas has a weak effect on the meso-macropore structure. Moreover, as apparent aromaticity (fa) increases, maximum surface free energy of coal sample increases linearly and the initial isosteric heat of adsorption increases exponentially, respectively. Above all, gas adsorption energy variation affects methane adsorption capacity, then it is also influenced by the micro-pore and internal chemical structure.

Sustainable Encapsulation Strategy of Silicon Nanoparticles in Microcarbon Sphere for High-Performance Lithium-Ion Battery Anode

Owing to the high theoretical capacity, low operating potentials, and natural abundance, silicon (Si) is considered as one of the most promising anode materials for lithium-ion batteries. However, a large volume change during alloying–dealloying often results in pulverization, electrical contact loss, and unstable solid-electrolyte interphase (SEI) formation, leading to rapid capacity fading. We present a rational encapsulation strategy of a silicon–carbon (Si–C) composite as a high-performance anode material for lithium-ion batteries (LIBs). The Si–C composite material is prepared via a one-pot hydrothermal method by using silicon nanoparticles modified using an etching route and sucrose as a carbon precursor. The proposed Si–C composite material has a meso-macroporous structure and contains a large weight fraction of silicon nanoparticles (40 wt %) encapsulated in a micrometric carbon sphere (∼3 μm). In the composite material, the carbon framework tightly encapsulates the silicon nanoparticles to the interior of the particle, which not only provides electrical conductivity but also decreases the stress/strain of the material during the alloying–dealloying process. The material demonstrates high initial capacity of 1300 mAh g–1, excellent capacity retention of 90% after 200 cycles, and fast charging–discharging capability within 12 min. We believe that the proposed encapsulation strategy here will be helpful in developing a high-energy and low-cost Si–C composite anode.

Self-standing zeolite foam monoliths with hierarchical micro-meso-macroporous structures.

The zeolite monoliths were synthesized by a facile polymer scaffold template assisted hydrothermal method. The selected foam-shaped template of a polyurethane (PU) foam monolith, was used to prepare the self-standing zeolite foam (ZF) monolithic materials. The obtained ZF products can preserve the same size, shape and macroporous network structure of the original PU foam scaffold template, although the zeolite nano-crystallites had been fully substituted for the PU template to form the new skeleton struts and walls. The as-synthesized ZF products demonstrated abundant hierarchical porosity (involving triple micro-, meso- and macropores). Meanwhile, compared with the conventional zeolite powders, the self-standing ZF monolithic materials exhibited greater total pore volume and nearly three times higher mesopore volume, suggesting wider applications as catalysts, catalyst supports and adsorbents in industry.

Metal Ti quantum chain-inlaid 2D NaSn2(PO4)3/H-doped hard carbon hybrid electrodes with ultrahigh energy storage density

We report the development of a new hybrid electrode that allows for a reinforcing combination of different energy storage mechanisms, providing enhanced energy and power densities. This hybrid electrode is composed of chain-like metal titanium (zero valency state) quantum dots (<10 nm), two-dimension NaSn2(PO4)3 layer and H-doped hard carbon layer, and possesses unique sandwich and hierarchically meso-macroporous structures. These chain-like quantum dots are inlaid on the edge of ultra-thin NaSn2(PO4)3 nanosheets by using a convenient and economic method, enhancing its conductivity. This design takes advantage of the unique properties of each component and nanostructure, resulting in synergistic effects to improve the charge transfer and energy storage. The hybrid electrode not only shows high capacity, outstanding rate performance and long cycling stability, but also matches well with porous Na3V2(PO4)3 cathode. Remarkably, the Na/Li mixed-ion full battery exhibits significant improvements on the energy and power densities (555 Wh Kg−1/804 W Kg−1 at 1C). Detailed charge storage mechanism investigation reveals that the prelithiation reduces the pseudocapacitive of hybrid electrode and increases its battery behavior, resulting in an ultrahigh energy storage density. Our findings demonstrate that this hybrid electrode is a new potential candidate for high-performance mixed-ion batteries.