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Bismuth sulfide (Bi2S3) has attracted particular interest as a potential anode material for sodium-ion batteries (SIBs). However, the low electrical conductivity and dramatic volumetric change greatly restrict its practical applications. In view of the apparent structural and compositional advantages of metal-organic frameworks (MOFs) derived carbon-based composite, herein, as a proof of concept, Bi2S3 spheres coated with the MOF-derived Co9S8 and N-doped carbon composite layer (Bi2S3@Co9S8/NC composite spheres) have been rational designed and synthesized. As expected, the core-shell Bi2S3@Co9S8/NC composite spheres exhibit remarkable electrochemical performance in terms of high reversible capacity (597 mAh g−1 after 100 cycles at 0.1 A g−1), good rate capability (341 mAh g−1 at 8 A g−1) and long-term cycling stability (458 mAh g−1 after 1000 cycles at 1 A g−1) when investigated as anode materials for SIBs. Electrochemical analyses further reveal the favorable reaction kinetics in the Bi2S3@Co9S8/NC composite spheres. In addition, the possible sodium storage mechanism has been studied by ex-situ X-ray diffraction technique. More importantly, a sodium-ion full cell based on Na3V2(PO4)3/rGO as cathode and Bi2S3@Co9S8/NC as anode is also fabricated, suggesting their potential for practical applications. It is anticipated that the present work could be extended to construct other advanced electrode materials using MOFs-derived carbon-based composites as surface coating materials for various energy storage-related applications.

A metal–organic framework (MOF) thin film constructed from Zn nodes and naphthalenediimide (NDI) linkers was grown in-situ uniformly on a transparent conducting glass substrate. This transparent thin film exhibits intriguingly high-contrast electrochromic (EC) switching between canary yellow and dark brown by means of a one-electron redox reaction at its NDI linkers. The findings provide a basic comprehension of the relations between redox state and electrochromism and enrich the application of MOF in the field of optoelectronic materials.

Directly growing nickel/cobalt-based cathode materials on current collectors as binder-free electrodes for rechargeable aqueous nickel/cobalt-Zn-based (NiCo//Zn) batteries have attracted tremendous attentions. However, most of the present binder-free cathodes suffer from low areal capacity and energy density, which severely restrict their practical applications. Herein, we demonstrate an efficient metal-organic framework (MOF)-involved strategy to rationally integration of the active NiCo2O4, CoMoO4 and Co3O4 cathode materials into one hierarchical arrayed structure that uniformly grown on nickel foam (NF) substrate (denoted as NF–NCO@CMO@CO) with a high mass loading of 9.6 ​mg ​cm−2. Such electrode design possesses favorable merits in the aspects of high electrical conductivity, robust arrayed architectures, abundant electrochemical active sites, rich redox reactions, facile ion diffusion and components’ synergetic effect. As a result, the aqueous NiCo//Zn battery based on NF–NCO@CMO@CO binder-free cathode exhibits an ultrahigh areal capacity of 2.51 ​mAh cm−2 at a current density of 2 ​mA ​cm−2, as well as good rate capability and long-term cycling stability. Impressively, the aqueous NF–NCO@CMO@CO//Zn battery shows a maximum areal energy density of 4.09 ​mWh cm−2 (corresponding to 424.5 ​Wh kg−1), which is superior to most of the previously reported aqueous NiCo//Zn batteries. Electrode reaction kinetics analysis reveals that both capacitive and diffusion-controlled behaviors are involved during the charge storage processes. Moreover, a quasi-solid-state NF–NCO@CMO@CO//Zn battery is also assembled by replacing the liquid electrolyte with gel electrolyte, suggesting the potential for practical applications. This work might shed light on the rational construction of advanced binder-free cathodes for high-performance aqueous NiCo//Zn batteries.

Traditional slurry-based electrodes consist of heavy current collectors and electroactive materials with a low weight percentage, which inevitably increase the total weight and cost of lithium-ion batteries (LIBs). Consequently, the development of low-cost, lightweight, flexible and binder-free electrodes for LIBs is highly desirable but also greatly challenging. In this work, we report the synthesis of small ZnO nanoparticles uniformly embedded in N-doped carbon (NC) nanoplate arrays (NPAs) tightly grown on a N-doped carbon paper (NCP) substrate (ZnO/NC NPAs@NCP) through a facile metal-organic framework-engaged strategy. This electrode design not only avoids the utilisation of insulating polymer binders but also offers other advantages, including large electrode/electrolyte contact areas, abundant electroactive sites, good wettability of the electrolyte, fast electron/ion transport and efficient volume accommodation. Notably, the freestanding ZnO/NC NPAs@NCP electrode displays a high reversible capacity of 610 mA h g−1 (based on the mass of entire electrode) at a current density of 100 mA g−1 for 50 cycles and excellent long-term cycling stability (363 mA h g−1 at 500 mA g−1 for 200 cycles). Furthermore, a full cell employing ZnO/NC NPAs@NCP as the anode and commercial LiFePO4 as the cathode is constructed, indicating the feasibility for practical application. Moreover, an analysis of the electrode kinetics confirms the favourable lithium-ion storage kinetics within the ZnO/NC NPAs@NCP electrode. The present work could provide a new approach to develop low-cost, lightweight and flexible electrodes for advanced energy storage.

The development of hollow structures with structural and composition complexity are highly attractive in the field of energy storage. In the present work, we demonstrate the rational construction of unique heterostructured core-shell Bi2S3@Co9S8 complex hollow particles (CHPs) through a facile metal-organic framework (MOF)-engaged strategy, in which the Bi2S3 spheres are well confined in the Co9S8 multi-cavity hollow shells. Benefiting from the specific structural and composition advantages, the core-shell Bi2S3@Co9S8 CHPs exhibit remarkable Li- and Na-ion storage performance in the aspects of high reversible capacity, excellent rate performance and long-term cycling stability. Electrochemical analyses reveal fast reaction kinetics in the core-shell Bi2S3@Co9S8 CHPs. Meanwhile, a Bi2S3@Co9S8//LiFePO4 full cell is successfully fabricated to evaluate their potential for real applications. In addition, the possible reaction mechanisms of the core-shell Bi2S3@Co9S8 CHPs for both Li- and Na-ion storage have been investigated via ex situ X-ray diffraction technique. Furthermore, density functional theoretical calculations confirm the heterostructure in the Bi2S3@Co9S8 CHPs can enhance the electrical conductivity and reaction kinetics. This work may offer new opportunities for integration of two active anode materials with high capacity and electrochemical activity into one heterostructured complex hollow structure.

Manganese-based oxides with high capacity and moderate operation voltage have been extensively studied as promising cathode materials for aqueous zinc ion batteries (ZIBs). However, the inherent poor electrical conductivity, sluggish reaction kinetics, huge volume expansion and dissolution of manganese species in electrolyte greatly restrict their practical applications. Herein, ultrasmall ZnMn2O4 nanodots uniformly anchored on reduced graphene oxide with strong interfacial interaction (ZnMn2O4 NDs/rGO composite) is synthesized. Compared with the pure ZnMn2O4 microspheres, the ZnMn2O4 NDs/rGO composite displays a much higher discharge capacity of 207.6 mA h g−1 at a current density of 0.2 A g−1, as well as better rate capability and long-term cycling stability. Impressively, the aqueous Zn//ZnMn2O4 NDs/rGO battery exhibits a high energy density of 266 W h kg−1 at a power density of 137 W kg−1, indicating great potential for practical applications. The excellent performance could be attributed to the abundant active sites, shortened ion diffusion pathway, improved electrical conductivity and good structure stability. Furthermore, electrochemical analyses reveal that favorable reaction kinetics towards efficient zinc ion storage is achieved in the composite. The present work might shed light on the rational design and synthesis of advanced strongly coupled graphene based composites as cathode materials for aqueous ZIBs.

Here we present the design and synthesis of a new robust microporous organic polymer (TPBP) decorated with phenazine groups which endowed reversibly redox-active properties. The obtained TPBP possesses relatively high surface area (359 m2/g) and good thermal stability. TPBP exhibits excellent catalytic capability for the oxidative homocoupling of amines with high activity and selectivity toward target products. Besides, this metal-free catalyst demonstrated excellent recyclability after 6 cycles under the investigated conditions. By means of EPR and UV-vis spectroscopy, a plausible mechanism of the amine oxidative coupling reaction was deduced via a single electron transfer from TPBP radical cations to amine substrates.

Mixed transition metal sulfides (TMSs) with hollow and complex hollow structures have attracted intensive attentions as high-performance cathode materials for rechargeable alkaline batteries. However, these powder-based electrode materials should be further mixed with insulative polymer binders and suffered from complicate electrode fabrication process. Herein, for the first time, we demonstrate the delicate design and synthesis of the sugar gourd-like multi-component yolk-shell Ni–Mo–Co–S nanocage arrays (NCAs) on Ni foam (NF) through a facile metal-organic framework (MOF)-engaged strategy. The synthetic process includes the growth of Co-based zeolitic imidazolate framework (ZIF-67) polyhedra onto the NiMoO4·xH2O nanorod arrays (NRAs) at room temperature and followed by a sufficient sulfidation reaction. Benefiting from the intriguing structural and compositional advantages, the yolk-shell Ni–Mo–Co–S NCAs/NF binder-free electrode exhibits an extremely high areal capacity of 1.96 mAh cm−2 at a current density of 5 mA cm−2 and excellent cycling stability. The electrode kinetics analysis confirms the diffusion-controlled battery-type behavior of the yolk-shell Ni–Mo–Co–S NCAs/NF electrode. The corresponding full cell delivers an high energy density of 92.6 Wh kg−1 at the power density of 1029.1 W kg−1 with the yolk-shell Ni–Mo–Co–S NCAs/NF as cathode electrode and Bi2O3 as anode electrode, indicating the potential for real applications. This work would make contribution to the realization of directly growing multi-component hollow and complex hollow structures on conductive substrate for high-performance electrochemical energy storage.

Although metal-organic framework (MOF) glasses have exhibited high potential to be applied as anode materials for lithium-ion batteries (LIBs), their electrochemical performances still need to be greatly improved to match the rapid development of green energy technologies. Silicon is a promising candidate for the next generation of LIB anode but suffers from vast volume fluctuations upon lithiation/delithiation. Here, we present a strategy to in situ grow a kind of MOF, namely, cobalt-ZIF-62 (Co(imidazole)1.75(benzimidazole)0.25) on the surface of Si nano particles, and then to transform the thus-derived material into Si@ZIF-glass composite (SiZGC) through melt-quenching. The robust hierarchical structure of the SiZGC based anode exhibits the specific capacity of ∼650 mA h g-1, which is about three times that of pure ZIF glass and about six times that of pristine ZIF crystal at 1 A g-1 after 500 cycles. The origin of this huge enhancement is revealed by performing structural analyses. The ZIF glass phase can not only contribute to lithium storage, but also buffer the volume changes and prevent the aggregation of Si nano particles during lithiation/delithiation processes.

Developing facile strategies to synthesize transition metal oxides and nitrogen-doped carbon (NC) hybrid materials is important for lithium-ion batteries (LIBs) but also challenging. Herein, unique one-dimensional multicomponent MoO2@CoO-CoMoO4-NC hybrid nanorods have been successfully synthesized. Benefiting from the unique morphology, structure and components, the MoO2@CoO-CoMoO4-NC hybrid nanorods exhibit a high reversible discharge capacity of 1164.0 mA h g−1 at 200 mA g−1 for 80 cycles, good rate performance (394.5 mA h g−1 at 4000 mA g−1) and cycling stability (688.8 mA h g−1 at 1000 mA g−1 for 350 cycles). It is believed that the MoO2@CoO-CoMoO4-NC hybrid nanorods could be very promising anode materials for LIBs.

In solid oxide fuel cells (SOFCs), it is important that the sealing glass has adequate mechanical strength (rigidity) to withstand stack loads while simultaneously having appropriate resiliency to release the internal stress and thus resist cracking. However, at present, sealing glass is either resilient or rigid. Animal teeth exhibit a bilayer structure that combines remarkable surface hardness to withstand mastication loads with the high resiliency of the inner layer to resist crack propagation. Drawing from this, in this study, we selected a heat-treatment temperature of 700 °C to simulate the operating temperature of the sealing glass and SOFCs, and carried out experimental and theoretical investigation of a typical borosilicate sealing-glass system. The results revealed that surface strengthening occurs within 200 nm depth as the heat-treatment time increases; that is, there is a gradient change in the mechanical property from the surface to the interior of glass, indicating that the surface has greater hardness and elastic modulus to bear stack loads, while the interior has better resiliency and may help resist crack initiation and propagation. A possible mechanism for this strengthening is proposed. The 4-coordinated B and Al centred BO4 and AlO4 can form a glass network structure with SiO4 (i.e., B–O–Si, Al–O–Si), which may lead to surface strengthening due to the increase in the degree of network crosslinking.

Heptazine units with highly rich nitrogen sites were employed to fabricate a new porous organic polymer (POP-HE) via direct coupling of 2,5,8-trichloro-s-heptazine and 4,4′,4″,4‴-(ethene-1,1,2,2-tetrayl)tetraaniline with the mild base N, N′-diisopropylethylamine (DIPEA) in tetrahydrofuran (THF) solution. POP-HE displays good CO2 uptake capacity (50.6 cm3 g−1, 10 wt%, 1 bar/273 K) and highly selectively adsorptive separation of CO2 over CH4 under ambient conditions. Impressively, at 273 K, the predicted IAST selectivity of POP-HE is 47.0-13.4 for the natural gas mixture (CO2/CH4 = 5:95) at pressures varying from 0 to 1 atm. Meanwhile, the result of calculated band gap value based on Tauc plot motivated us to investigate its photocatalytic activity. POP-HE was applied as heterogeneous photocatalyst for visible light-induced selective oxidation of benzyl alcohol to benzaldehyde, and exhibited great conversion of 33.6% under irradiation of white LED light, which is much higher than that of g-C3N4. Moreover, POP-HE can be recycled up to three times without significant decrease in catalytic activity.

Crack formation at the interface between sealing glass and other cell components is one of the key issues in constraining the development of solid oxide fuel cells (SOFCs). Herein, we report our finding on tuning the mechanical and thermal properties of borosilicate glass by doping Nb2O5. We observe the formation of Ba3Nb10O28 crystalline phase in the Nb2O5-doped glass, leading to significantly enhanced crack-resistant and self-healing abilities of the glass. In addition, we demonstrate long-term thermal and chemical stability at the sealing interface between the Nb2O5-doped glass-ceramics and Y2O3-ZrO2 electrolyte after heat-treatment at 700 °C for 1000 h. The possible mechanism for the improved crack-resistant and self-healing properties is discussed.

Metal-organic frameworks (MOFs) derived ternary transition metal oxide nanostructures have attracted considerable attention for their important applications in energy-related fields. However, most of the present reports on MOFs-derived materials are in the powder form, which should be further mixed with polymer binder and conductive agents before they are coated on current conductor. In this work, we demonstrate a facile solution method to grow the bimetallic zinc/cobalt zeolitic imidazolate frameworks nanoplate arrays (Zn/Co-ZIF NPAs) on carbon cloth (CC) substrate and then they are well converted to porous ternary ZnCo2O4 NPAs on CC after an annealing treatment in air. When investigated as binder-free electrodes for lithium-ion batteries (LIBs), the ZnCo2O4 NPAs/CC electrode exhibits a high area capacity of 3.01 mA h cm−2 (corresponding to 1341.7 mA h g−1 for the ZnCo2O4 NPAs) at the current density of 0.24 mA cm−2 for 100 cycles, which is much higher than that of the Co3O4 NPAs/CC electrode (1.93 mA h cm−2). Moreover, at a high current density of 1.20 mA cm−2, the ZnCo2O4 NPAs/CC electrode can still maintain a high capacity of 2.05 mA h cm−2. The excellent electrochemical performance could be attributed to the unique morphology, structure and composition of the porous ternary ZnCo2O4 NPAs, as well as directly grown on current collector.

Rational design and synthesis of advanced sulfur host materials has been regarded as an effective strategy to address the critical challenges of lithium-sulfur (Li-S) batteries including shuttle effect of lithium polysulfides (LiPSs), sluggish reaction kinetics, and huge volume change of sulfur. In this work, we demonstrate the rational construction of a multifunctional sulfur host grown on carbon cloth consisting of self-supported porous VN arrays coupled with MOF-derived N-doped carbon nanotubes embedded with tiny Co nanoparticles (named CC/VN/Co@NCNTs). This unique electrode design possesses a series of advantages such as high electrical conductivity, strong physical/chemical confinement of LiPSs, favorable catalytic activity, fast reaction kinetics, effective volumetric accommodation, good mechanical stability and high sulfur loading. As expected, when evaluated as self-standing and binder-free cathode for Li-S batteries, the CC/VN/Co@NCNTs/S exhibits a high initial discharge capacity of 1130.4 mAh g−1 at 0.1C and maintains 864.1 mAh g−1 after 100 cycles, along with outstanding rate performance (625.3 mAh g−1 at 5C) and superior long-term cycling stability with a low capacity decay rate of 0.063% per cycle at 1C for 500 cycles. Moreover, the CC/VN/Co@NCNTs/S delivers high reversible capacities of 847.6, 668.3, and 581.1 mAh g−1 at 0.1C after 100 cycles at different high sulfur loadings of 2.8, 5.2, and 7.8 mg cm−2, respectively. The present work might provide an effective strategy to directly construct multifunctional sulfur host materials on current collectors for high-performance Li-S batteries.

Construction of heterogeneous nanostructures for electrode materials has been considered as an efficient approach to improve the associated electrochemical performance, it is thus crucial to rationally design favorable heterostructures and engineer the interface of two phases. We herein report the elaborately design and fabrication of heterostructured nanohybrids with ZnS and carbon coating Cu2S nanoplates (Cu2S@ZnS/C). Such distinctive nanostructures develop the advance heterostructures with carbon decorating can remarkably accelerate electron transfer and ionic diffusion kinetics while guarantee the structural integrity upon sodium ion storage. With these merits, the Cu2S@ZnS/C nanohybrid exhibits outstanding electrochemical performance with a high reversible capacity of 352 mAh g−1 at 10 A g−1 and long cycle stability with 94.7% capacity retention after 1000 cycles. Electrochemical kinetic analysis and Density functional theory (DFT) calculations demonstrate the decreased ions diffusion energy barrier for expediting electrochemical kinetics. Of note, the proof-of-concept 3D printed sodium ion batteries have been set up by coupling the 3D printed Cu2S@ZnS/C anode with 3D printed Na3V2(PO4)3 cathode, which are capable of delivering high and stable capacity output.

Synthesis of nanostructured composites containing multiple components with distinctive structure and composition is important for high-performance energy storage but challenging. Starting form metal-organic frameworks (MOFs), we herein successfully synthesize a series of advanced nanocomposites consisting of composition-tailored nickel cobalt sulfoselenide (NiCo2(SxSe1−x)5) nanoparticles confined in graphitic carbon hollow spheres (GC HSs). For pseudocapacitors, the NiCo2(S0.78Se0.22)5/GC HSs exhibit the highest specific capacity (560.7 C g−1 at 1 A g−1) with good rate capability and cycling performance. An asymmetric supercapacitor (ASC) based on the NiCo2(S0.78Se0.22)5/GC HSs cathode and Bi2O2.33/rGO nanocomposite anode displays an energy density of 47.2 Wh kg–1 at a high power density of 801 W kg–1. Besides, the NiCo2(S0.78Se0.22)5/GC HSs are also promising anode materials for lithium-ion batteries, which deliver a high reversible capacity of 865.2 mA h g−1 at 200 mA g−1 after 100 cycles. The excellent performance could be attributed to the high electrical conductivity, facile electron and ion transport, good structural robustness and components’ synergistic effect. We believe this synthetic strategy could be extended to prepare other anions doped bimetallic compounds and carbon composites for next-generation energy storage.

Construction bimetallic transition metal selenides with complex hollow structures is of significant importance but also extremely challenging. In this work, starting form metal-organic frameworks (MOFs), we have successfully synthesized the unique hierarchical (Ni0.33Co0.67)Se2 complex hollow spheres (CHSs), which manifest high specific capacitance as well as excellent rate performance and cycling stability, making them promising electrode materials for pseudocapacitors. The hierarchical (Ni0.33Co0.67)Se2 CHSs display a high specific capacitance of 827.9 F g−1 at the current density of 1 A g−1 and can still retain 646.2 F g−1 at a very high current density of 30 A g−1. Besides, a high capacitance of 865.8 F g−1 is obtained after cycling at 6 A g−1 for 2000 cycles, indicating good cycling stability. The excellent electrochemical performance could be owing to their high electrical conductivity and hierarchical complex hollow structure. Furthermore, an asymmetric supercapacitor (ASC) device employing (Ni0.33Co0.67)Se2 CHSs as positive electrode and activated carbon (AC) as negative electrode is also fabricated, which displays a high energy density of 29.1 Wh kg−1 at a power density of 800 W kg−1. These electrochemical results indicate the hierarchical (Ni0.33Co0.67)Se2 CHSs could be promising electrode materials for pseudocapacitors. The present work might also contribute to the rational construction of metal selenides with complex hollow structures for high-performance energy storage.

Three porous lanthanide metal-organic frameworks (Ln-MOFs) [Ln(BCB)(DMF)]∙(DMF)m(H2O)n (Ln = Yb3+ (1), Er3+ (2), Dy3+ (3), DMF = N,N′-dimethylformamide) have been successfully prepared using 4,4′,4″-benzenetricarbonyltribenzoic acid (H3BCB) as organic linkers. X-ray diffraction analysis reveals that these ketone group decorated complexes are isostructural, and each form a three-dimensional structure possessing two types of one-dimensional channels along the c axis. Moreover, the near-infrared luminescence properties of the three complexes were also investigated.

Exploring suitable electrode materials with high rate capability and long-term cycling stability for sodium-ion batteries (SIBs) is of great importance but still challenging. In this work, we report a facile strategy to synthesize the nanocomposite of porous NaTi2(PO4)3 nanoparticles coated with a thin carbon layer (NTP/C). The unique structural and component merits endow the NTP/C nanocomposite with excellent charge transfer kinetics and enhanced structural stability. Compared with the pristine NTP nanoparticles, the NTP/C nanocomposite exhibits significant enhanced rate capability (108.9 mA h g−1 at 0.2C and 55.0 mA h g−1 at 20C) and long-term cycling performance (capacity retention of 78.8% after 2000 cycles at 10C). The electrochemical results indicate the NTP/C nanocomposite could be a high-performance anode material for SIBs.

Borate bioactive glass (BBG) stimulates angiogenesis and promotes cell growth. However, controlling the degradation rate of BBG and maintaining the critical concentration of bioactive ions suitable for cell promotion and differentiation remain great challenges in soft tissue repair. In this study, a novel approach was proposed to produce nanosized CO32−-containing hydroxyapatite (HCA)-coated BBG (nano-HCA@BG). Unlike the previously reported hard-to-degrade hydroxyapatite (HA) coating after static soaking treatment of BBG, the nano-HCA@BG, obtained by dynamically immersing the BBG powder in a flowing buffer, had a porous structure and was surface-coated with a layer of amorphous HCA, which improved the biocompatibility and retained the biodegradability of BBG. The effects of nano-HCA@BG were evaluated and compared with those of powdered BBG at the cellular and animal levels. The formation of the HCA-coated nanoporous architecture significantly improves biocompatibility, promotes cell growth and proliferation, and is beneficial for wound healing in rodent skin defects.

Manganese oxide and carbon hybrid materials have attracted intensive research attention as advanced electrode materials for energy storage. Herein, starting form metal-organic frameworks (MOFs), the nanocomposites of mixed-valent manganese oxide nanoparticles in-situ grown on ultrathin carbon sheets (MnOx-CSs nanocomposites) have been synthesized via a simple method. Benefiting from the unique structural merits, the nanocomposite obtained at 600 °C (MnOx-CSs-600) exhibits excellent performance for both supercapacitors (SCs) and lithium-ion batteries (LIBs). A high specific capacitance of 220 F g−1 is achieved at the current density of 1 A g−1. An asymmetric supercapacitor (ASC) based on the MnOx-CSs-600 nanocomposite cathode and activated carbon anode exhibits a high energy density of 27.5 W h kg−1 at the power density of 225 W kg−1. Moreover, the MnOx-CSs-600 nanocomposite displays a high reversible capacity of 1217.7 mA h g−1 at 200 mA g−1 after 160 cycles as an anode material for LIBs. Remarkably, the discharge capacity is still as high as 612.1 mA h g−1 even at high current density of 2000 mA g−1, indicating good rate capability. This synthetic strategy is quite simple, cost-effective and environmental friendly, which is highly promising for scaled-up production.

Herein, a novel highly selective thin-film composite (TFC) forward osmosis (FO) membrane with high water flux (Jw) and low reverse salt flux (Js) was fabricated with a rationally designed sulfonated covalent organic frameworks (COFs) as an interlayer. This membrane was designed to be negatively charged, hydrophilic and has the synergistic effect of the selective rejection ability of the COFs. The sulfonation of the COFs enhanced its hydrophilicity, offered negative charges and narrowed its pore size, benefiting the salt rejection. Hydrolyzed nylon membrane support with freed surface amino groups was firstly reacted with trimesoyl chloride (TMC) to become hydrophilic and negatively charged. The sulfonated COFs was then firmly mounted on the modified support via H-bonding. A PA layer was finally formed on the support via interfacial polymerization. The prepared TFC-FO membrane overcame the trade-off between Jw and Js with an enhanced FO permeation and superior selectivity (Jw/Js = 24.7 L/g) in FO mode. Both the sulfonated COF interlayer and TMC modification of nylon support were tested to be crucial to the high performance. The new strategy reported here paves a way for taking the advantages of COFs for preparing high-performance FO membranes.

Binary metal sulfides have been considered as promising electrode materials for supercapacitors with excellent performance. Herein, we demonstrate a simple two-step hydrothermal method to grow the interconnected Co9S8/NiCo2S4 nanosheet arrays (denoted as Ni-Co sulfide NSAs) on nickel foam with robust adhesion for high performance supercapacitors. Remarkably, the as-synthesized Ni-Co sulfide binder-free electrode exhibits an ultrahigh areal capacitance of 7.4 F cm−2 for supercapacitors, which is about five times higher than 1.5 F cm−2 of the Ni-Co oxide electrode at the current density of 5 mA cm−2. The Ni-Co sulfide binder-free electrode also exhibits a good cycling stability, which still displays a high capacitance retention of 90.7% after 2000 cycles even at a high current density of 40 mA cm−2. The good electrochemical performance could be ascribed to the high electrical conductivity and porous nanosheet structure of the Ni-Co sulfide nanosheets, as well as the robust adhesion with the current collector. These electrochemical results suggest that such Ni-Co sulfide NSA binder-free electrode might hold some potential for electrochemical energy applications.

Graphene and metal oxide nanocomposites have been demonstrated as promising electrode materials for high-performance lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). In this work, ultrafine CoMn2O4 nanoparticles uniformly anchored on reduced graphene oxide (rGO) sheets have been synthesized through a facile and effective two-step strategy. Owing to the rational combination of merits from both ternary CoMn2O4 and graphene sheets, the as-synthesized rGO/CoMn2O4 nanocomposite exhibits remarkable Li-battery performance with high reversible capacity, good cycling stability and excellent rate performance. Remarkably, the rGO/CoMn2O4 nanocomposite displays high reversible capacities of 1102.1 and 811.1 mA h g−1 at the current densities of 200 and 500 mA g−1 after 60 cycles, respectively. The discharge capacities of the rGO/CoMn2O4 nanocomposite are as high as 851.1, 835.3, 795.2, 755.9, 694.0, and 563.6 mA h g−1 at the current densities of 100, 200, 500, 1000, 2000 and 5000 mA g−1, respectively. These electrochemical results suggest the rGO/CoMn2O4 nanocomposite could be a promising anode material for high-performance LIBs. Besides, the rGO/CoMn2O4 nanocomposite also exhibits comparably promising electrochemical performance as an anode material for SIBs. Our study also highlights the importance of rational synthesis of graphene-based nanocomposite materials for high-performance LIBs and SIBs.

Construction of metal oxide/sulfide and carbon-based material nanocomposites is an effective strategy to obtain high-performance electrode materials for supercapacitors. In the present work, graphene oxide nanofibers (GONFs) are selected as the support materials, and the nanocomposite of reduced graphene oxide nanofiber and cobalt sulfide (rGONF/CoS2) is synthesized via a simple and facile method. As an electrode material for pseudocapacitors, the rGONF/CoS2 nanocomposite exhibits a high specific capacitance of 635.8 F g-1 at a current density of 1 A g-1 measured in 6 M KOH electrolyte, which is much higher than that of bare cobalt sulfide. Furthermore, the rGONF/CoS2 nanocomposite has also shown excellent cycling performance with 95.4% capacitance retention over 2000 cycles. In addition, the assembled asymmetric supercapacitor (ASC) device using rGONF/CoS2 nanocomposite as cathode material and activated carbon (AC) as anode material can work at a high operating voltage of 1.65 V and show a maximum energy density of 13.8 W h kg−1 at a power density of 824.6 W kg−1.

Nanostructured ZnO and ternary Zn-based oxides have been regarded as promising anode materials for lithium ion batteries. In the present work, we report a facile and simple method to synthesize the highly porous ZnO/ZnFe2O4 hybrid nanostructures using the prussian blue analogue as the sacrificial template. The synthetic process only contains the room temperature synthesis of the precursor with a subsequent annealing treatment. Benefiting from their unique structural/component merits, the ZnO/ZnFe2O4 hybrid nanostructures exhibit excellent lithium-storage performance as anode materials. The first discharge capacity is as high as 998.4 mA h g−1, and a high reversible discharge capacity of 704 mA h g−1 is still retained after 200 cycles, indicating good cycle stability. The porous ZnO/ZnFe2O4 hybrid nanostructures could be a high-performance anode materials for lithium ion batteries.

Defect-mediated engineering has been proven as a novel and effective strategy to integrate two individual materials into a nanocomposite to boost the performance. In the present work, nanocomposite of partially-unzipped stacked-cup carbon nanofibers (PUSCNFs) decorated with platinum nanoparticles (Pt NPs) have been successfully synthesized through the defect-mediated formation method. Owing to the introduction of abundant structural defects during the chemical oxidation process, Pt NPs with an average diameter of 2–3 nm were uniformly anchored on the PUSCNFs without any surfactant involved. As comparison, the Pt NPs grown on the stacked-cup carbon nanofibers (SCNFs) possessed markedly larger nanoparticle size and trended to aggregate. The electrochemical properties of the nanocomposite-modified electrodes for biosensing were examined. Our results showed the Pt-PUSCNFs nanocomposite possessed optimal electrocatalytic activities and biosensing performance for detection of biomolecules, which could be attributed to a synergistic effect between the PUSCNFs and Pt NPs on electron transport and catalytic properties. We anticipate that the PUSCNFs may be a potential support material for construction of nanocomposites with good performance.

In this work, N-doped carbon nanotubes (NCNTS) have been easily unzipped using a chemical oxidation method to obtain porous and multi-defective partially unzipped N-doped carbon nanotubes (PU-NCNTs), which are promising as negative electrode materials for supercapacitors and are also suitable substrate materials for the efficient loading of ultrathin manganese dioxide (MnO 2 ) nanosheets. Herein, the PU-NCNT/MnO 2 composite was synthesized through a simple microwave irradiation method. Moreover, we have fabricated an asymmetric supercapacitor (ASC) using PU-NCNT/MnO 2 composite as cathode, PU-NCNTs as anode and neutral aqueous Na 2 SO 4 as electrolyte. Because of the synergistic effects of the PU-NCNTs electrode and the high capacitance as well as good rate performance of PU-NCNT/MnO 2 composite, the asymmetric cell exhibited good electrochemical performance. The optimized ASC can be worked stably in the voltage window of 0–1.8 V and exhibited a maximum energy density of 14.76 Wh kg −1 at the current density of 1 A g −1 . Additionally, the PU-NCNT/MnO 2 //PU-NCNT ASC exhibited long cycling stability with 80.5% specific capacitance retained after 1000 cycles at a current density of 1 A g −1 . These encouraging results show that PU-NCNT/MnO 2 could be promising materials for commercial use of supercapacitors.

Detection of disease-related small biomolecules was of great significance for clinical diagnostics and treatment. In this work, we synthesized defect-rich knotted graphene nanotubes (k-GNTs) via chemical oxidative etching of stacked-up carbon nanotubes (SC-CNTs) followed by chemical reduction, to detect disease-related small biomolecules. We further studied the electrochemical properties using three representative redox probes and analyzed their biosensitivity using five biomolecules. The k-GNT-modified electrodes exhibited excellent electrochemical response, with the lowest Δ E p and the highest k 0 . Besides, the modified electrodes could simultaneously detect and discriminate between dopamine (DA), ascorbic acid and uric acid (UA), as well as differentiate phenethylamine (PEA) and epinephrine (EP) existed in newborn rat serum, providing the wide linear detection ranges with high sensitivities for DA, UA, PEA, and EP. These excellent electrocatalytic properties could be ascribe to the unique knotted graphene nanotube structure with high proportion of defect/edge sites, large, accessible, three-dimensional, accessible surface area, fewer oxygen-containing groups and doped N atoms. Our work reveals defect-rich k-GNTs as a promising platform for further applications in electrochemical biosensing and electrocatalysis.

The one dimensional (1D) carbon nanomaterials have been conceived as the suitable candidate for the biosensor, but the effect of their structures on the biosensing properties was deficient. Here, we chose carbon nanotubes (CNTs), graphene nanoribbons (GONRs) as models for 1D and quasi 1D carbon nanomaterials, and partially unzipped CNTs (PUCNTs) as an intermediate material, to investigate structure-dependent electrocatalysis of 1D carbon nanomaterials. The 1D to quasi 1D carbon nanomaterials with various surface areas, defect densities and oxygen contents were used to modify the electrodes and exhibited excellent electrocatalytic activities and performances towards UA and DA without the influence of AA. The CNTs with low oxygen and defect content helped to induce direct electron transfer and displayed a highest sensitivity; with abundant oxygen functional groups, the GONRs exhibited a broadest linear detection range; for the intermediate material, PUCNTs showed secondary electrochemical response for UA and DA. Additionally, the 1D carbon materials were applied in the real samples with satisfactory results. The 1D carbon materials demonstrated different electrochemical behaviors and thus can provide rational choices for developing higher sensitivity and wider linear range biosensors by optimizing and controlling the nanostructure.

Transition metal oxides (TMOs) with high capacity have been extensively studied as promising anode candidates for lithium-ion batteries (LIBs). However, the intrinsic low electrical conductivity, sluggish reaction kinetics and dramatic volume expansion greatly restrict their practical applications. In the present work, we delicate design and synthesis of an advanced composite consisting of multi-component CoO/MoO2/CoMoO4 hierarchical hollow nanocages anchored on reduced graphene oxide (named as Co–Mo–O NCs/rGO composite) with strong interfacial interaction. The hierarchical hollow structure is beneficial for large electrode/electrolyte contact area and fast ion diffusion. Meanwhile, graphene can provide rapid electron transport pathway and buffer the volume change. As a result, the Co–Mo–O NCs/rGO composite exhibits excellent lithium storage performance in aspects of high reversible specific capacity (964 mA h g−1 at 0.1 A g−1), good rate capability (333 mA h g−1 at 5 A g−1) and long-term cycling performance (731 mA h g−1 at 1 A g−1 after 400 cycles). Moreover, electrode kinetics analysis further reveals the capacitive-controlled lithium ion storage mechanism in the Co–Mo–O NCs/rGO composite. The present work would demonstrate the importance of integrating multi-component TMOs hierarchical hollow structures and graphene into one intriguing architecture to boost the electrochemical performance.

A novel microporous organic polymer TP-MOP containing Troger's base (TB) has been constructed by a simple one-pot reaction through the condensation of 1,3,6,8‐tetrakis(4‐aminophenyl)pyrene (TP) with dimethoxymethane (DMM) under ambient condition. The N2 adsorption isotherm of TP-MOP at 77 K indicates typical type-I sorption behavior with a Brunauer–Emmett–Teller (BET) surface area of 1066 m2 g−1. Fascinatingly, it exhibits high carbon dioxide adsorption capacity up to 254.6 cm3 g−1 at 1 bar, 273 K. Moreover, probably due to the presence of Troger's base moiety, the isosteric heat (Qst) of CO2 adsorption for TP-MOP can reach as high as 40.4 kJ mol−1. This consequently boosts the CO2 uptake and/or CO2 selectivity over nitrogen and methane. Impressively, at 278 K, the predicted IAST (the ideal adsorbed solution theory) selectivities of TP-MOP are 93-65.8 for a CO2/N2 (15/85 v/v) gas mixture and 8.3–6.7 for a CO2/CH4 (50/50 v/v) gas mixture at pressures varying from 0 to 1 atm, respectively.

Development of n-type polymer semiconductor materials for all-polymer solar cells (all-PSCs) receives increasingly attention. A series of new n-type random terpolymers with identical perylene diimide-thiophene alternating copolymer backbone and different composition of the side chains 2-octyldodecanyl and 2-ethylhexanyl have been designed and applied as the acceptor materials in all-PSCs. The all-PSCs based on bulk heterojunction blends with side-chain engineered random terpolymer P(1/1) as acceptor and PTB7-Th as donor give a high power conversion efficiency value of 6.18% with an open-circuit voltage of 0.74 V, a short-circuit current density of 14.71 mA cm−2, and a fill factor of 0.57. The results demonstrate that design of the poly(perylenediimide-alt-thiophene) random terpolymer acceptors via side-chain engineering is an alternative strategy for obtaining high-performance photovoltaic acceptor materials.

Defect rich partially unzipped N-doped carbon nanotubes (PU-NCNTs) were synthesized by the chemical unzipped N-doped carbon nanotubes (NCNTs). Compared with NCNTs, PU-NCNTs exhibit faster electron transfer kinetics in representative inner- and outer-sphere redox probes as well as higher selectivity and sensitivity toward dopamine detection. These properties are due to their unique caterpillar-like carbon nanotube–graphene complex structure with high proportion of defect/edge sites, large accessible surface area and high electrical conductivity, thus reveals as a promising platform for further applications in electrochemical sensing. Keywords: Partially unzipped N-doped carbon nanotubes, Edge-plane sites, Surface defects, Redox probes, Dopamine

Despite several pioneering work, the fundamental study of partially unzipped carbon nanotubes (PUCNTs) as an electrode material has hardly been done. In this work, we synthesized PUCNTs by solution-based longitudinal unzipping of carbon nanotubes (CNTs) and rigorously studied their electrochemical characteristics by using three representative redox probes. Electrochemical measurements reveal the superior electrochemical response of PUCNTs in comparison with CNTs, which can be attributed to the unique CNT–graphene complex structure of PUCNTs. Besides, for the three redox probes involved, the electron transfer kinetics of PUCNTs behave variously, indicating that the extent to which structural features affect electron transfer rates depends on the analytes. Our work suggests the great potential of PUCNTs as a sort of new electrode material for future electrochemical applications. Keywords: Partially unzipped carbon nanotubes, Electrochemistry, Redox probes, Edge-plane-like sites/defects, Oxygen-containing groups

The preparation and characterization of free-standing films made of a graphene oxide-carboxymethyl cellulose composite material is described. Characterization was accomplished using transmission electron microscopy, ultraviolet–visible absorption spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. The nonlinear optical performance of this composite material was studied using the open aperture Z-scan technique in the nanosecond regime using a 532-nm wavelength laser. Results show that the composite has nonlinear optical properties that are much enhanced when composited with graphene oxide. All phenomena indicate that the film is a potential candidate for optical limiting applications.

Nanostructured titanates were prepared by alkaline hydrothermal treatment of Ti powder and NaOH with different concentrations of NaCl solution. The products were characterized by X-ray diffraction, scanning electron microscopy, (high-resolution) transmission electron microscopy, and ultraviolet–visible absorbance, Fourier-transform infrared, and Raman spectroscopies. The effect on the titanate morphology of different concentrations of NaCl in the hydrothermal reaction system was investigated. In the presence of NaCl, Ti powder treated with NaOH initially formed three-dimensional nanobelt microspheres. Nanobelt growth along the [1 1 0] axis orientation was inhibited, and the nanobelts were transformed into wide nanoplates by radial growth. At high concentrations of NaCl, lamellar nanosheets were exfoliated from the large particles through dissolution–recrystallization, and finally rolled into nanotubes. The nonlinear optical (NLO) properties of different titanate nanostructures were studied using the open-aperture Z -scan technique, and a typical positive NLO effect induced by incident light was observed.

Poly(ethylene glycol) (PEG)/SiO2-CaO-P2O5 hybrid xerogels were prepared using a room temperature sol-gel process. The advantage of this hybrid material over conventional composites is the molecular scale interactions between the bioactive inorganic components and the biodegradable organic components. Since PEG was added into the sol when the hydrolysis of tetraethoxysilane occurred, the molecular chain of PEG was penetrated into the SiO2 networks to form a semi-IPN structure. Due to the excellent biocompatibility and aqueous solubility of PEG molecules, as well as the bioactivity of the inorganic components, the biological and mechanical properties of this hybrid xerogel exhibit great potential for bone regeneration applications. The formation of hydroxyapatite was observed when the xerogel was immersed into simulated body fluid, demonstrating good bioactivity of the hybrid. The cell toxicity test also demonstrated that the hybrid material is suitable for the proliferation of MC3T3-E1 cells. Thus, the PEG/SiO2-CaO-P2O5 hybrid xerogel has great potential to meet the demands of bone regeneration materials.

Multiwalled carbon nanotubes (MWCNTs) were individually coated with conducting, semiconducting, and insulating materials. The coatings used were crystalline Au nanoparticles, TiO2 nanoclusters, and amorphous SiO2 nanoshells, respectively. The synthesis strategy involves a combination of self-assembly and the sol–gel technique. The synthesized nanostructures were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, Raman spectroscopy, and X-ray diffraction. We investigated the nonlinear optical and optical limiting properties using an open-aperture Z-scan technique and fluence-dependent transmittance measurements. Compared to the pristine MWCNTs, those with Au-, TiO2-, and SiO2-coatings demonstrate superior, equivalent, and inferior nonlinear optical and optical limiting properties, respectively.

The sidewalls of multiwalled carbon nanotubes (MWCNTs) were decorated with CdS nanoparticles using a mild two-step approach, with in situ polymerized thiophene (PTh) acting as an interlinker. Extensive characterization of the materials has been carried out using transmission electron microscopy, selected area electron diffraction, X-ray diffraction, thermal gravimetric analysis, ultraviolet–visible absorption spectroscopy and photoluminescence spectroscopy. Optical limiting (OL) studies have been performed using the open Z-scan technique at the laser wavelengths of 532 and 1064 nm. The MWCNT–PTh–CdS system shows an enhanced OL effect in comparison to the pristine MWCNTs, particularly at 1064 nm. Possible underlying mechanisms are proposed based on the results of nonlinear scattering measurements.

We report the synthesis and characterization of multiwalled carbon nanotube (MWCNT)–organically modified silicate (ORMOSIL) nanohybrid gel glass, in which the incorporated MWCNTs are covalently bonded to the silica network. The structural properties of the 3-aminopropyltriethoxysilane functionalized MWCNTs and MWCNT–ORMOSIL nanohybrid gel glass are comprehensively characterized using spectroscopic and electron microscopy techniques. We find that the agglomeration of incorporated MWCNTs is effectively restrained and that the MWCNTs are dispersed homogeneously and individually in the gel glass matrix. Compared with the mother MWCNT suspension, the resultant nanohybrid gel glasses demonstrate sustained nonlinear optical properties at both 532 and 1064 nm laser wavelengths.

The fabrication of nanocomposites by covalent inclusion of inorganic nanoparticles in an organic polymer matrix is highly topical and may find applications in the electronics, optics and energy sectors. Incorporation of CdS nanoparticles into the polyacrylonitrile (PAN) matrices could be expected to display improved or enhanced optoelectronic and optical properties. Using a newly synthesized RAFT agent, i.e. , CdS-DDAT nanoparticles (DDAT: S-1-Dodecyl-S′-(α, α′-dimethyl-α′′-acetic acid) trithiocarbonate), CdS covalently functionalized polyacrylonitrile (CdS-PAN) nanocomposite material was prepared in the presence of small amount of AIBN under ultrasonic radiation. This material, which exhibits an induced positive nonlinear absorption of incident light, has been well-characterized by a variety of physical techniques such as GPC, UV/vis, FT-IR, TGA, XRD and Z-scan.