Controllable Pore Research Articles

Underwater superoleophobic paper-based materials with controllable pore structure for emulsified oil separation

Underwater superoleophobic paper-based materials with controllable pore structure for emulsified oil separation

A novel pH- and glutathione-responsive drug delivery system based on in situ growth of MOF199 on mesoporous organic silica nanoparticles targeting the hepatocellular carcinoma niche

BackgroundFor people with advanced hepatocellular carcinoma (HCC), systemic chemotherapy remains the only choice of palliative treatment. However, chemotherapy efficacy is not effective due to its short blood circulation times, nonspecific cell and tissue biodistribution, and rapid metabolism or excretion from the body. Therefore, a targeted nanomedicine delivery system is urgently needed.MethodsIn order to improve the treatment efficiency of HCC, based on in situ growth of a copper metal organic framework on mesoporous organic silica nanoparticles, dual pH- and glutathione (GSH)-responsive multifunctional nanocomposites were synthesized as nanocarriers for enhanced HCC therapy. In this research, cellular uptake studies were performed using CLSM and Bio-TEM observations. Flow cytometry, AO-EB fluorescent staining, EdU test and Western blot were utilized to explore the apoptosis and proliferation process. In vivo imaging was employed to research the distribution of the nanocomposites in HCC tumor-bearing nude mice and the xenograft model of HCC tumor-bearing nude mice was applied to investigate the anti-tumor effects of drug-loaded nanocomposites in vivo.ResultsThis newly constructed degradable nanocomposite DOX/SOR@SP94 and mPEG-anchored MONs@MOF199 (D/S@SPMM) has the benefits of controllable pore size, high encapsulation efficiency, and precise targeting. According to the results of in vivo imaging and anti-tumor studies, as well as pharmacokinetic research, D/S@SPMM possessed precise HCC tumor targeting and long-lasting accumulation properties at the tumor region. Compared with traditional chemotherapy and non-targeted drug delivery systems, anti-tumor efficiency was increased by approximately 10- and 5-fold, respectively. The nanocomposites exhibited excellent anti-tumor properties without inducing observable systemic toxicity, owing to efficient DOX and SOR loading and release as well as the HCC specific targeting peptide SP94.ConclusionsThe in vitro and in vivo anti-tumor results indicated that these nanocomposites could be an efficient nanomedicine for targeting HCC therapy.

A high-protein retained PES hemodialysis membrane with tannic acid as a multifunctional modifier

A high protein retention polyethersulfone (PES) membrane was prepared by nonsolvent-induced phase separation and surface coating, which exhibited enhanced hemocompatibility and antioxidant stress performance. The cross-linked network was constructed by tannic acid (TA) and alpha-lipoic acid (α-LA) on the surface of the membrane, which controlled the pores to a reasonable size. The enrichment of heparin-like groups on the membrane surface, implemented by “hydrophobic interaction” and “click reaction”, confers anticoagulant properties; the presence of a large number of phenolic hydroxyl groups from TA and the introduction of α-LA allows the modified membranes to intervene in oxidative stress. The hemocompatibility characterizations included plasma recalcification time (PRT), activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT) and hemolysis rate (HR). Additionally, the DPPH ABTS radical scavenging capacity was tested to evaluate the antioxidant performance. The results show that the modified membrane presents an outstanding protein retention rate (99.3%) along with permeability. In addition, the PRT is prolonged to 341.7 s, and the DPPH• scavenging ability reaches 0.74 µmol•cm-2. The membranes can be easily prepared and present excellent comprehensive performance. This work provides a simple and facile strategy for the fabrication of hemodialysis membranes with controllable pore sizes.

Bamboo cellulose-derived activated carbon aerogel with controllable mesoporous structure as an effective adsorbent for tetracycline hydrochloride.

Activated carbon has been widespread applied in the removal of pollutants in wastewater. However, many biomass-derived activated carbon suffer from the challenge of controllable pore size regulation, hindering their efficient adsorption of pollutants. Herein, bamboo-derived activated carbon aerogel (BACA) has been successfully prepared through KOH high-temperature activation of cellulose aerogel which was prepared using cellulose extracted from bamboo. Bamboo cellulose aerogel provides sufficient reaction sites for KOH, which is conducive to the formation of a mass of mesoporous structures on the pore walls of the activated carbon aerogel. The optimal BACA adsorbent shows high specific surface area (2503.80 m2/g), and maximum adsorption capability for tetracycline hydrochloride (TCH) reaches 863.8mg/g at 30 ℃. The removal efficiencies of TCH are 100% and 98.4% at 40 ℃ when the initial concentrations are 500 and 700mg/L, respectively. Adsorption kinetics and isotherm indicate that the adsorption of BACA for TCH is monolayer adsorption based on chemical adsorption. Spontaneous and endothermic adsorption processes are proved by adsorption thermodynamic studies. Additionally, coexisting ions have insignificant effect on TCH adsorption, and the BACA sample displays excellent adsorption property for five reuse cycles with a removal efficiency of 80.95%, indicating the outstanding adsorption capacity of BACA in practical application. The excellent adsorption performance provides BACA with a promising perspective to remove TCH from wastewater, and the prepared method of BACA can be widely extended to other biomass materials.

Efficacy Studies of Silica Nanoparticles Synthesized Using Agricultural Waste for Mitigating Waterborne Contaminants

In recent years, there has been a steady increase in the quantity of agricultural waste generation, due to the increased production of the food supply chain and the production of fuel for greenhouse gas (GHG) emission reduction initiatives, viz. processing, and consumption. As a result, there have been a number of environmental concerns, such as waste disposal, governance, and environmental impact. Hence, repurposing such wastes into high-value goods such as silica nanoparticles (SNPs) has received a lot of scientific attention. Because of their controllable pore size, large surface areas, and tunable and tailorable structure, SNPs have attracted interest from scientists for a variety of applications. As the water resources are becoming scarce and heavily stressed, our ongoing efforts have been towards the green synthesis of nanoparticles, with an emphasis on mitigating waterborne contaminants. Recent advances in the synthesis of SNPs from barley and rice husk agricultural waste, as well as its use in the removal of several recent environmental pollutants from water, have attracted the attention of several researchers, including our group. By fine-tuning the processing parameters during synthesis, the characteristics of SNPs are altered in terms of their configuration, appearance, porosity, and dimensions. Such features and corresponding applications of the SNPs are being investigated in order to investigate whether agricultural waste may be utilized for silica precursors. Although the utilization of low-cost waste-derived minerals appears to have the potential for both waste reduction and the creation of value-added goods, further studies are needed to increase silica production, particularly on a commercial scale. In addition, we conducted a review of the efficacy of SNPs toward water contamination mitigation and our results of such investigation are reported here. It is observed that silica nanoparticles can be synthesized on a commercial scale using green chemistry principles and are highly efficient materials with promising outcomes for environmental applications. Hence, using green synthesis, we are able to reduce agricultural waste, while mitigating environmental contaminants using environmentally friendly processing.

Facile, Direct, De Novo Synthesis of an Alkyl Phosphoric Acid-Decorated Covalent Organic Framework.

The development and understanding of proton conductors based on phosphoric acid are critical for the field of chemistry, biology, and energy. Covalent organic frameworks (COFs), featuring highly crystalline structures and controllable pore sizes, are suitable for constructing phosphoric acid-based proton conductors. However, because of tedious and intricate synthesis, how to develop COFs based on phosphoric acid remains a substantial challenge. Herein, a side-chain decorated strategy is contributed to construct a phosphoric acid-functionalized, imine-linked COF by de novo synthesis. The phosphoric acid side chains with vigorous motion integrating with 1D nanochannels endow the resulting COF with intrinsic proton conductivity. This work expectantly provides a competitive alternative for producing phosphoric acid-functionalized COFs with high intrinsic proton conductivity.

Optimisation of the additive manufacturing parameters of polylactic acid (PLA) cellular structures for biomedical applications

Fused deposition modelling (FDM) is an additive manufacturing technology used to create functional and complex geometries directly from computer-generated models. This technique can be utilised to generate cellular structures with controllable pore size, pore shape, and porosity. Cellular structures are fundamental in orthopaedics scaffolds because of its low elastic modulus, high compressive strength, and adequate cell accommodation spaces. This paper aims at investigating and optimising the FDM additive manufacturing process parameters of polylactic Acid (PLA) for two lattice structures namely Schoen Gyroid and Schwarz Primitive. The effect of additive manufacturing critical process parameters including layer height, flow rate, and print speed on the geometrical accuracy and compressive strength of the specimens were analysed. In addition, other parameters that have minimal effect on the geometrical accuracy of the printed parts were discussed. A Full Factorial Analysis (FFA) using Minitab software was undertaken to identify the perfect combination of printing parameters to provide the most geometrically accurate structure. In this study, samples of the Schoen Gyroid and the Schwarz Primitive lattices and a solid control cylinder were 3D printed using the ideal printing combination to assess the manufacturability, the geometrical accuracy, and the mechanical behaviour of both designs. It was found that the optimised FDM process parameters for the studied cellular structures were a layer height of 0.16 mm, a printing speed of 50 mm/s and a flow rate of 90%. As a result of using these parameters, the solid, Schoen Gyroid and Schwarz Primitive specimens demonstrated elastic moduli values of 951 MPa, 264 MPa, and 221 MPa, respectively. In addition, the Schoen Gyroid and the Schwarz Primitive have reached their stress limits at around 8.68 MPa and 7.06 MPa, respectively. It was noticed that the Schoen Gyroid structure exhibited ∼ 18% higher compressive strength and ∼ 16% higher elastic modulus compared to the Schwarz Primitive structure for the same volume fraction of porosity, overall dimensions, and the manufacturing process parameters. Although both structures revealed mechanical properties that fall within the range of the human trabecular bone, but Schoen Gyroid exhibited improved structural integrity performance that is evident by its post-yield behaviour.

Bimetallic Metal-Organic Framework Fe/Co-MIL-88(NH2) Exhibiting High Peroxidase-like Activity and Its Application in Detection of Extracellular Vesicles.

Metal-organic frameworks (MOFs) have many attractive features, including tunable composition, rigid structure, controllable pore size, and large specific surface area, and thus are highly applicable in molecular analysis. Depending on the MOF structure, a high number of unsaturated metal sites can be exposed to catalyze chemical reactions. In the present work, we report that using both Co(II) and Fe(III) to prepare the MIL-88(NH2) MOF, we can produce the bimetallic MOF that can catalyze the conversion of 3,3',5,5″-tetramethylbenzidine (TMB) to a color product through a reaction with H2O2 at a higher reaction rate than the monometallic Fe-MIL-88(NH2). The Michaelis constants (Km) of the catalytic reaction for TMB and H2O2 are 3-5 times smaller, and the catalytic constants (kcat) are 5-10 times higher than those of the horseradish peroxidase (HRP), supporting ultrahigh peroxidase-like activity. These values are also much more superior to those of the HRP-mimicking MOFs reported previously. Interestingly, the bimetallic MOF can be coupled with glucose oxidase (GOx) to trigger the cascade enzymatic reaction for highly sensitive detection of extracellular vesicles (EVs), a family of important biomarkers. Through conjugation to the aptamer that recognizes the marker protein on EV surface, the MOF can help isolate the EVs from biological matrices, which are subsequently labeled by GOx via antibody recognition. The cascade enzymatic reaction between MOF and GOx enables the detection of EVs at a concentration as low as 7.8 × 104 particles/mL. The assay can be applied to monitor EV secretion by cultured cells and also can successfully detect the different EV quantities in the sera samples collected from cancer patients and healthy controls. Overall, we prove that the bimetallic Fe/Co-MIL-88(NH2) MOF, with its high peroxidase activity and high biocompatibility, is a valuable tool deployable in clinical assays to facilitate disease diagnosis and prognosis.

Insights into the KOH activation parameters in the preparation of corncob-based microporous carbon for high-performance supercapacitors

High-performance supercapacitors extremely depend on reasonable microstructure of electrode materials, but how to efficiently control the pore structure of principal carbon materials remains a challenge. In this study, corncob-based porous carbon (CPCX) with controllable pore structures is synthesized by means of KOH activation strategy, and the technical parameters of KOH activation are comprehensively investigated including activation temperature, activation time and KOH/biochar ratio. The optimal sample with a KOH/biochar mass ratio of 3 activated at 650 °C for 1 h (denoted as CPC650–1-3) possesses sub-nanopores concentrated at 0.6 nm and 0.8 nm, and larger micropores distribute at 1.2 nm and 1.5 nm. These highly cross-linked microporous structures provide accessible specific surface area (SSA) for electrode materials and act as high-speed channels for fast ion diffusion and transfer. The activated carbon material has a high SSA (2998 m2 g−1) and a large Vmicro/Vmeso ratio of 8.26. The specific capacitance of CPC650–1-3 reaches 258 F g−1 at 0.5 A g−1 and remains a satisfied retention of 74 % even at 10 A g−1. Moreover, CPC650–1-3//CPC650–1-3 symmetric supercapacitors exhibit a high energy density of 6.4 Wh kg−1 at power density of 500.1 W kg−1. It also has a capacitance retention of 90.1 % after 10,000 cycles, highlighting its excellent cycle stability. These results indicate that corncob-based microporous carbon materials have broad application prospects in promoting the high added-value utilization of biomass waste and the development of high-performance supercapacitors.

Amine-Modified Small Pore Mesoporous Silica as Potential Adsorbent for Zn Removal from Plating Wastewater

The removal of Zn from wastewater generated from the Zn-based electroplating manufacturing process is essential because the regulation limit of Zn concentration in wastewater is becoming stricter in Japan. However, achieving this through conventional methods is difficult, especially for small and medium enterprises in the plating industry. Therefore, a suitable Zn-removal method with a low cost but high performance and Zn selectivity is required. The application of adsorbents is one possible solution. Mesoporous silica (MS) is a well-known adsorbent with controllable pore size, high specific surface area (SSA), high acid resistance, and ease of surface modification. In this study, we modified the surfaces of MSs with different initial pore sizes by amino groups and investigated their Zn removal performances. The effect of pore size on amine modification using (3-aminopropyl)triethoxysilane and on adsorption performance in a single system was investigated along with Zn adsorption selectivity in the Zn–Ni binary system. Amine-modified MS prepared from MS with an initial pore size of 1.9 nm showed drastically lower performance compared to those prepared from MS with an initial pore size larger than 2.8 nm. Zn-selectivity in the Zn–Ni binary system, containing equal amounts of Zn and Ni, was found to reach a maximum of 21.6 when modifying MS with an initial pore size of 2.8 nm.

Porous geopolymer with controllable interconnected pores—a viable permeable reactive barrier filler for lead pollutant removal

Most of the commonly used traditional permeable reactive barrier (PRB) fillers have many drawbacks, such as poor retention of hydraulic conductivity, high cost, and a complex preparation process. Porous geopolymers (PGPs) with controllable pore structures could circumvent these drawbacks owing to their high adsorption capacity, cost-effective synthesis, and good chemical stability. In this study, based on our previous research, the “foaming-liquid film” balance control method was proposed and used to fabricate three PGPs with gradient pore connectivity. The influence of pore structure on the Pb2+ removal performance and migration mechanism were investigated by conducting both batch and column experiments. Closed, dead-end, capillary, and interconnected pores exist in the PGPs, and results indicated that interconnected pores effectively promote the migration of solute in the main flow channels to the deeper matrix, thereby enhancing the long-term dynamic removal efficiency. At breakthrough, the Pb2+ uptake of PGP-3 reached 146 mg g−1. Further, the proposed “foaming-liquid film” balance control method is effective to prepare PGPs with controllable connectivity, and the PGP-PRBs with a high proportion of interconnected pores exhibit excellent performance for the removal of heavy metals, which is advantageous for their future applications in groundwater decontamination.

Lanthanum zirconate porous ceramics with controllable secondary pores for high-temperature thermal insulation

It was an effective way to tailor the pore structure of porous ceramics to enhance the thermal insulating properties at a large temperature range. In this study, a feasible method combining the particle-stabilized foaming method and the pore-forming agent method was developed to fabricate hierarchically porous lanthanum zirconate (LZO) ceramics with ultra-high porosity (P) and controllable secondary pores. With the increasing pore-forming agent (carbon) to 40 vol%, the total porosity reached 95.79 ± 0.08% with secondary pores of 0.47%. The ratio of secondary pores to cell wall increased from 2.39% to 11.17%. Due to the increase of secondary pore percentage, the thermal conduction path increased and the infrared radiation was scattered. Consequently, the thermal conductivity, k, at room temperature was reduced from 0.082 ± 0.001 W/(m·K) to 0.061 ± 0.002 W/(m·K), and the k at 1200 °C decreased from 0.379 ± 0.011 W/(m·K) to 0.317 ± 0.011 W/(m·K). The results provided a feasible method to prepare porous ceramics with controllable pore structure for thermal insulation application.

In-Built Fabrication of MOF Assimilated Porous Hollow Carbon from Pre-Hydrolysate for Supercapacitor.

With the fast consumption of traditional fossil fuels and the urgent requirement for a low-carbon economy and sustainable development, supercapacitors are gaining more and more attention as a clean energy storage and conversion device. The research on electrode materials for supercapacitors has become a hot topic nowadays. An electrode material for a supercapacitor, comprising the ZIF-67 in-built carbon-based material, was prepared from a biomass pre-hydrolysate via a hydrothermal process. As a by-product of dissolving slurry, the pre-hydrolysate is rich in carbon, which is an excellent biomass resource. The utilization of pre-hydrolysate to prepare carbon energy materials could realize the high value utilization of pre-hydrolysate and the efficient energy conversion of biomass. Meanwhile, the cobalt-based MOF (such as ZIF-67), as a porous crystalline material, has the advantages of having a regular order, high specific surface area and controllable pore size, as well as good thermal and chemical stability. The addition of ZIF-67 modified the morphology and pore structure of the carbon, and the obtained samples showed outstanding electrochemical performance. One- and two-step synthetic processes generated specimens with a coral-like cross-linked structure and a new type of rough, hollow, dandelion-like structure, respectively, and the pore size was in the range of 2.0–5.0 nm, which is conducive to ion transport and charge transfer. In C2-ZIF-67, the hollow structures could effectively prevent the accumulation of the electrochemical active center, which could provide enough space for the shrinkage and expansion of particles to protect them from the interference of electrolytes and the formation of solid electrolyte interphase film layers. Additionally, the plush tentacle structure with low density and a large specific surface area could expose more active sites and a large electrolyte electrode contact area, and short electron and charge transport paths. Importantly, active, free electrons of small amounts of Co-MOF (1 wt%) could be stored and released through the redox reaction, further improving the electrical conductivity of Carbon-ZIF-67 materials in this work. Consequently, C2-ZIF-67 exhibited superior specific capacitance (400 F g−1, at 0.5 A g−1) and stability (90%, after 10,000 cycles).

Superhydrophilic PVDF nanofibrous membranes with hierarchical structure based on solution blow spinning for oil-water separation

Nanofibrous membranes (NFMs) are frequently used in oil-water separation thanks to their high porosity, controllable pore size, and convenience in modification to obtain super wettability. However, the low production rate and dense structure of NFMs have limited the industrial applications. In this work, zinc oxide (ZnO) seed loaded polyvinylidene fluoride (PVDF) NFMs with fluffy structure were prepared through solution blow spinning (SBS). Subsequently, ZnO nanowires (NWs) were synthesized based on the seeds through ultrasonic assisted hydrothermal reaction, constructing superhydrophilic surface with hierarchical structure. The u-ZnO-NWs/PVDF showed uniform morphology throughout the entire membrane with an average fiber diameter of 517.35 ± 158.72 nm and an average nanowire diameter of 72.55 ± 20.52 nm, which resulted in a low average pore size (4024.68 ± 393.40 nm), superhydrophilicity, and underwater oleophobicity. The nanowire equipped membrane revealed super high water flux (12960.77 ± 325.04 L·m−2·h−1·bar−1), which could be applied in the separation of oil-in-water emulsions with high separation efficiency (>97 %) and high flux (about 8000 L·m−2·h−1·bar−1) under gravity. Results indicated the potential of SBS u-ZnO-NWs/PVDF in the fields of oil-water separation, sewage treatment, as well as catalytic degradation.

Synthesis and Mechanical Properties of Polyacrylamide Gel Doped with Graphene Oxide

Polyacrylamide (PAM)/polyethyleneimine (PEI) gels doped with graphene oxide (GO) were prepared. Their structure and properties were systematically studied by X-ray diffraction (XRD), Fourier transition infrared spectrum (FT-IR), Raman spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and rheological experiments. The results showed that the graphene oxide (GO) nanosheets were significantly involved in the cross-linking reaction between the main agent (PAM) and the cross-linker (PEI), serving as multi-functional cross-linker and effective reinforcing nanofillers. Increasing the main agent and cross-linker content, the strength of gels was enhanced effectively. The GO could effectively adjust the strength and the gelation time to exhibit characteristics of weak gel, thanks to the improved three-dimensional honeycombed structure with controllable pore size. The DSC confirmed that the PAM/PEI/GO gel exhibited excellent thermal stability and did not dehydrate above 170 °C. This work provides theoretical support for further optimization of polyacrylamide gel used in ultra-deep and high-temperature reservoirs for water control.

Construction of 3D Ordered Honeycomb Films with Controllable Pores as Efficient Catalytic Supports

AbstractThe facile construction of 3D porous film using the breath figure technique is critically important in diverse practical applications. However, the discovery of easy synthetic methods and preparation of stimuli‐responsive 3D ordered nano‐/micro‐architectures remain challenging. Herein, the promotive breath figure technique is presented to construct 3D honeycomb porous films on curved substrates using an azobenzene‐containing copolymer. The nanopore size of honeycomb structure decreases gradually with the increase of surface curvature, due to the different solvent drying speeds. Upon irradiation with directional linear polarization light, the round‐shaped nanopores are converted into rectangular‐ and rhombic‐shaped nanopores under different polarization directions. Moreover, these porous films are employed as substrates to load various metal nanoparticles, successfully preparing the nanocomposites. The catalytic capacity of both control and these nanocomposites are evaluated using the NaBH4‐mediated reduction reaction from 4‐nitrophenol to 4‐aminophenol. Compared to the control and nonporous films, the porous films with smaller nanopores exhibit larger catalytic activity. Additionally, UV irradiation upon the nanocomposites promotes the catalytic action, due to the change in surface hydrophilicity caused by the photoisomerization of azobenzene. Recyclable use of nanocomposites demonstrates the high stability. This research provides an innovative strategy to prepare 3D curved porous films for potential on catalysis.

Zn5(OH)6(CO3)2-assisted controlled fabrication of microcrystalline cellulose-derived hierarchical porous carbon for high-performance lithium storage

The proper N doping engineering and microstructure design are of essential importance to develop advanced carbon anodes for Li-ion batteries. Herein, a facile strategy was developed to fabricate hierarchical porous carbon with controllable pore structures, N doping content and configurations, which was easily realized via introducing zinc salt as recyclable activator and regulator in the precursors. The zinc salt could not only function as pore-forming agent to facilitate the formation of hierarchical porous defect-rich structure, but also act as N-confined reactor to preserve the N-containing intermediates and promote N doping in the carbon matrix during thermal conversion. Specifically, 21.7% N content (increased by 115%) which was mainly composed of pyridinic/pyrrolic N (88.6%) was achieved with the addition of Zn5(OH)6(CO3)2. Meanwhile, desirable mesopore-dominant hierarchical porous carbon with appropriate specific surface area was obtained. Benefiting from the unique microstructure and N functionalities, the NC-Zn5(OH)6(CO3)2 anode delivered a high reversible capacity of 564 mAh g−1 at 200 mA g−1 over 100 cycles, which was almost two times higher than those for NC, and remarkable long-term cycling stability with high coulombic efficiency around 100% after 1300 cycles at 1000 mA g−1. This work provides an intriguing and feasible avenue for the reasonable structure design of carbon material with superior electrochemical performance for sustainable energy storage.

NiO/nitrogen-oxygen co-doped carbon nanoflower composites based on covalent organic frameworks for lithium-ion battery anodes

Designing novel NiO/porous carbon nanocomposites is an effective strategy to improve poor conductivity and rapid capacity fading of NiO in lithium-ion batteries (LIBs). Covalent organic frameworks (COFs) are attractive materials for LIBs as they have large specific surface areas, well-ordered structure, and controllable pore size. Here, we designed a COFTpPa nanoflower as templates for the preparation of porous carbon and a carrier for NiO to obtain NiO/nitrogen-oxygen co-doped carbon nanoflower (NiO/NCF) composites. NiO nanostructures have a smaller volume effect, and the coating of carbon nanoflowers can further buffer the volume expansion of NiO nanostructures, which effectively slow down the capacity decay. In addition, the NCF derived from COFTpPa provide a larger specific surface area and more pores, which not only increases the capacity of nanocomposites but also improves the electrical conductivity of the electrodes. When applied to the anode of LIBs, NCF and NiO/NCF exhibit excellent performance (with first-cycle capacities of 1038.2 and 1685.9 mAh g−1, respectively, and high first coulomb efficiencies of 61.5 % and 60.9 %, respectively). The designed NiO/NCF nanocomposites is a promising anode material for LIBs.

Nanoarchitectonics of the cathode to improve the reversibility of Li-O2 batteries.

The strategic design of the cathode is a critical feature for high-performance and long-lasting reversibility of an energy storage system. In particular, the round-trip efficiency and cycling performance of nonaqueous lithium–oxygen batteries are governed by minimizing the discharge products, such as Li2O and Li2O2. Recently, a metal–organic framework has been directly pyrolyzed into a carbon frame with controllable pore volume and size. Furthermore, selective metallic catalysts can also be obtained by adjusting metal ions for outstanding electrochemical reactions. In this study, various bimetallic zeolitic imidazolate framework (ZIF)-derived carbons were designed by varying the ratio of Zn to Co ions. Moreover, carbon nanotubes (CNTs) are added to improve the electrical conductivity further, ultimately leading to better electrochemical stability in the cathode. As a result, the optimized bimetallic ZIF–carbon/CNT composite exhibits a high discharge capacity of 16,000 mAh·g−1, with a stable cycling performance of up to 137 cycles. This feature is also beneficial for lowering the overpotential of the cathode during cycling, even at the high current density of 2,000 mA·g−1.

Rational design of self-sacrificial template derived quasi-Cu-MOF composite as anodes for high-performance lithium-ion batteries

MOF-based composites have aroused widespread concern due to their controllable morphology and pore characteristics. Nevertheless, the poor conductivity and volume expansion hinder its practical application in LIBs. Herein a classical structure HKUST-1, as the precursor, was used to fabricate quasi-Cu-MOF composite through a facile thermal decomposition strategy. The results showed that quasi-Cu-MOF composite had superior reversible specific capacity (627.5 mAh/g at 100 mA/g) and outstanding cycle stability (514.6 mAh/g at 500 mA/g after 400 cycles) as anodes for LIBs. The results demonstrated that the low-temperature calcination strategy played a significant role in morphology retaining during cycling and the derived copper framework play a crucial part in conductivity improvement. This work is helpful to the design of high-performance electrodes with advanced three-dimensional hierarchical structures.