Controllable synthesis of nickel doped hierarchical zinc MOF with tunable morphologies for enhanced supercapability.

Metal-organic frameworks (MOFs) are attracting tremendous research interest because of their rich redox sites and high specific area which are beneficial for the energy storage applications. Nevertheless, the poor conductivity, low mechanical strength and unsatisfactory capacity severely hinder their wide application. Hence, it is of practical significance to design highly efficient and facile strategy to solve these issues. Herein, vertically oriented ZnO nanorod arrays are applied as precursor to synthesize laminated scale-like and highly-oriented Ni/Zn-MOF/ZnO nanocomposite. Owing to the desirable conductivity resulting from the doping nickel ions and the interaction between ZnO and its relative MOF, the fabricated 0.3Ni/Zn-MOF/ZnO@CC electrode exhibits an electrochemical capacitance of 1693 mF cm-2 at 1 mA cm-2. Moreover, the electrochemical capacitance retention of 80.7 % after 2500 cycling numbers is obtained under the constant current density of 10 mA cm-2 and the low internal resistance Rs of 0.89 Ω is observed. For practical application, the as-synthesized laminated scale-like Ni/Zn-MOF/ZnO@CC nanocomposite is served as positive electrode to fabricate solid-state asymmetric supercapacitor device. Moreover, a 2.5 V indicator could be powered for 8 min when the prepared supercapacitor units are connected. This work demonstrates the promising potential of the synthesized scale-like Ni/Zn-MOF composites for electrochemical energy storage applications.

Hollow 3D Frame Structure Modified with NiCo2 S4 Nanosheets and Spinous Fe2 O3 Nanowires as Electrode Materials for High-Performance All-Solid-State Asymmetric Supercapacitors.

Supercapacitors have attracted tremendous research interest, since they are expected to achieve battery-level energy density, while having a long calendar life and short charging time. Herein, a novel asymmetric supercapacitor has been successfully assembled from NiCo2 S4 nanosheets and spinous Fe2 O3 nanowire modified hollow melamine foam decorated with polypyrrole as positive and negative electrodes, respectively. Owing to the well-designed nanostructure and suitable matching of electrode materials, the assembled asymmetric supercapacitor (ASC) exhibits an extended operation voltage window of 1.6 V with an energy density of 20.1 Wh kg-1 at a power density of 159.4 kW kg-1 . Moreover, the ASC shows stable cycling stability, with 81.3 % retention after 4000 cycles and a low internal resistance of 1.03 Ω. Additionally, a 2.5 V light-emitting diode indicator can be lit up by three ASCs connected in series; this provides evidence of the practical application potential of the assembled energy-storage system. The excellent electrochemical performances should be credited to the significant enhancement of the specific surface area, charge transport, and mechanical stability resulting from the unique 3D morphology.

Cobalt/Nickel Ions-Assisted Synthesis of Laminated CuO Nanospheres Based on Cu(OH)2 Nanorod Arrays for High-Performance Supercapacitors.

The development for environmentally friendly energy conversion and storage equipment has given rise to tremendous research efforts as a result of the growing requirements for environmental friendly resources and the rapid consumption of traditional fossil fuel. Herein, a novel hierarchical CoO/NiO-Cu@CuO heterostructure is successfully devised and synthesized. Cobalt/nickel ions are used to generate novel CoO/NiO-doped laminated CuO nanospheres through the facile in situ wet oxidation combined with cation exchange and calcination strategies. As a result, the electrochemical supercapacitance of the as-prepared CoO/NiO-Cu@CuO electrode can reach 875 C cm-2 (2035 mF cm-2), which exhibits much better electrochemical performance compared to other precursor electrodes at a same current density of 2 mA cm-2. Moreover, an excellent rate capacity of 1395 mF cm-2 (50 mA cm-2) can be achieved when measured at a relative high current density; 90.3% of the initial supercapacitance remains even after 5000 cycles. Furthermore, the as-prepared hierarchical hybrid of laminated CoO/NiO-CuO nanospheres in situ generated on three-dimensional (3D) porous Cu foam is applied to prepare a solid-state asymmetric supercapacitor equipment unit. The fabricated equipment unit shows an energy density of 69.3 W h kg-1 at a power density of 1080 W kg-1. Additionally, the commercially applied 2.5 V light-emitting-diode indicator with blue light can be energized for 4 min when two as-fabricated supercapacitor devices are in series connection. The unique hierarchical heterostructure of the novel laminated nanospheres combined with the 3D grid structure brings about the outstanding electrochemical capacitor performances. This strategy for the fabrication of hierarchical heterostructure electrodes could have an enormous potential for high-performance electrochemical equipment.

Synthesis of polypyrrole coated melamine foam by in-situ interfacial polymerization method for highly compressible and flexible supercapacitor.

Compressible and flexible supercapacitors have aroused enormous interest of many scientific researchers for potential applications in wearable electronic products. However, the design and construction of the electrode with superior mechanical as well as electrical properties still face a lot of challenges. In present work, melamine foam/polypyrrole (MF/PPy) electrode with high deformation-tolerance and excellent electrochemical performance is prepared by in-situ interfacial polymerization of polypyrrole on commercial melamine foam, where PPy nanoparticles with size of 700 nm are uniformly anchored on the MF skeletons. The electrochemical characterizations show that the electrode exhibits excellent specific area capacitance of 2.685 F cm-2 at 2 mA cm-2 and good cyclic stability with more than 80% of capacitance remained after 3000 cycles. Furthermore, a symmetrical aqueous supercapacitor is assembled and exhibits an excellent energy density up to 75.95 µWh cm-2 at the power density of 5.82 mW cm-2 and excellent cycling stability as the current density increases by 10 times. Even under a high strain of 70%, about 95.76% of the initial capacitance is retained after 500 consecutive compressions. These outstanding performances enable the MF/PPy composite a promising candidate for potential applications in compressible and flexible electrochemical energy storage devices.

Recent Advances in Functional-Polymer-Decorated Transition-Metal Nanomaterials for Bioimaging and Cancer Therapy.

In this review, we focus on recent advances in the synthesis of polymer-functionalized transition-metal-based nanomaterials and follow this up by discussing their applications in bioimaging diagnosis and cancer therapy. Transition-metal-based nanomaterials show great potential in cancer therapy owing to their intensive near-IR absorption, excellent photothermal conversion efficiency, strong X-ray attenuation, and magnetic properties. Functional polymers are usually introduced by a one-step or multistep method to further endow these nanomaterials with great biocompatibility and physiological stability. Polymer-decorated transition-metal nanomaterials show great potential in multimodal imaging diagnosis (photoacoustic imaging, computed tomography, photoluminescence imaging, positron emission tomography, etc.) and cancer therapy (chemotherapy, photothermal therapy, microwave therapy, radiotherapy, photodynamic therapy). At the end of this review, the prospects of these polymer-decorated transition-metal-based nanomaterials are also discussed.

Polymer-Based Nanocarriers for Co-Delivery and Combination of Diverse Therapies against Cancers.

Cancer gives rise to an enormous number of deaths worldwide nowadays. Therefore, it is in urgent need to develop new therapies, among which combined therapies including photothermal therapy (PTT) and chemotherapy (CHT) using polymer-based nanocarriers have attracted enormous interest due to the significantly enhanced efficacy and great progress has been made so far. The preparation of such nanocarriers is a comprehensive task involving the cooperation of nanomaterial science and biomedicine science. In this review, we try to introduce and analyze the structure, preparation and synergistic therapeutic effect of various polymer-based nanocarriers composed of anti-tumor drugs, nano-sized photothermal materials and other possible parts. Our effort may bring benefit to future exploration and potential applications of similar nanocarriers.

Recent Advances in Functional Polymer Decorated Two-Dimensional Transition-Metal Dichalcogenides Nanomaterials for Chemo-Photothermal Therapy.

Novel nanomaterials and advanced nanotechnologies continue to promote the fast development of new approaches for efficient tumor therapy. As an alternative choice to various traditional therapies, non-invasive photothermal therapy (PTT) has attracted significant attention mainly due to its low cost, highly localizing, specific tumor treatment and minimal side effects on healthy tissues. PTT induced by photo-absorbing agents which can absorb and convert the external NIR laser into heat to ablate tumors. Plenty of studies have shown the significant potential of PTT to treat tumors in future practical applications. However, PTT alone usually could not eradicate tumors considering the intensity of laser gradual attenuates in biological tissues and the heat generated tends to distribute inhomogeneous within tumors tissues. Combination of chemotherapy with photothermal therapy into one system for tumor therapy is an effective strategy to further improve the therapy efficiency. In this Minireview, we focus on the recent advances in constructing PTT therapeutic and multi-model combination therapeutic via integrating nanomaterials and functional polymers.

A Target-Directed Chemo-Photothermal System Based on Transferrin and Copolymer-Modified MoS2 Nanoplates with pH-Activated Drug Release.

Molybdenum disulfide (MoS2 ) nanosheets have attracted significant attention due to their photothermal properties, but the poor solubility and colloidal stability limited their further application in biomedical field. Here, we report a targeted photothermal controllable nanocarrier consisting of MoS2 nanosheets modified with block copolymer P(OEG-A)-b-P(VBA-co-KH570) and targeting ligand transferrin. P(OEG-A)-b-P(VBA-co-KH570) is synthesized by RAFT polymerization and utilized not only to improve the solubility of MoS2 nanosheets but also efficiently load the anti-cancer drug doxorubicin (DOX) through an acid-cleavable Schiff base linker. Thiol-functionalized transferrin (Tf-SH) is anchored onto the surface of MoS2 nanosheets by the formation of disulfide bonds, which could further enhance the cellular uptake of DOX and MoS2 to HepG2 cells for high-efficiency synergetic therapy. The drug release experiments exhibited the minimal release of DOX at room temperature and neutral pH, and the maximal drug release of 53 % at acidic tumor pH and hyperthermia condition after 48 h. In addition, the DOX-loaded, Tf-SH and P(OEG-A)-b-P(VBA-co-KH570) modified MoS2 (DOX-POVK-MoS2 -Tf) showed better a therapeutic effect than DOX-POVK-MoS2 and POVK-MoS2 , probably owing to the combined effects of target-directed uptake, acid-triggered drug release, and NIR induced localized heating, which suggest the designed MoS2 nanocarriers are promising for applications in multi-modal cancer therapy.

Transferrin-decorated, MoS2-capped hollow mesoporous silica nanospheres as a self-guided chemo-photothermal nanoplatform for controlled drug release and thermotherapy.

To improve cancer therapeutic efficacy and avoid side effects on normal tissues, a targeted chemo-photothermal nanoplatform was designed based on transferrin-decorated and MoS2-capped hollow mesoporous silica nanospheres. MoS2 nanosheets acted as a gatekeeper to prevent the leakage of DOX from the drug delivery system as well as the photothermal agent (PTA) to improve the therapeutic effect and facilitate the NIR-triggered endosomal escape. In this work, MoS2 nanosheets were anchored on the surface of hollow mesoporous silica nanospheres (HMSNs) via the formation of disulfide bonds (-S-S), which could be easily cleaved in the presence of the intracellular GSH, leading to stimuli-responsive drug release from the hollow mesoporous silica nanocarriers. Moreover, to further improve the tumor specificity and cellular uptake of the anti-cancer drug, the nanocarrier surface was also modified with the targeting ligand transferrin via-S-S linkage. The results demonstrated that the transferrin-decorated, MoS2-capped HMSNs can be utilized as a targeting chemo-photothermal synergetic system with high therapeutic efficacy.