Ultrasmall Coinage Metal Nanoclusters as Promising Theranostic Probes for Biomedical Applications.

Ultrasmall coinage metal nanoclusters (NCs, <3 nm) have emerged as a novel class of theranostic probes due to their atomically precise size and engineered physicochemical properties. The rapid advances in the design and applications of metal NC-based theranostic probes are made possible by the atomic-level engineering of metal NCs. This Perspective article examines (i) how the functions of metal NCs are engineered for theranostic applications, (ii) how a metal NC-based theranostic probe is designed and how its physicochemical properties affect the theranostic performance, and (iii) how metal NCs are used to diagnose and treat various diseases. We first summarize the tailored properties of metal NCs for theranostic applications in terms of biocompatibility and tumor targeting. We focus our discussion on the theranostic applications of metal NCs in bioimaging-directed disease diagnosis, photoinduced disease therapy, nanomedicine, drug delivery, and optical urinalysis. Lastly, an outlook on the challenges and opportunities in the future development of metal NCs for theranostic applications is provided.

Design of High-Capacity MoS3 Decorated Nitrogen Doped Carbon Coated Cu2 S Electrode Structures with Dual Heterogenous Interfaces for Outstanding Sodium-Ion Storage.

The hierarchical Cu2 S@NC@MoS3 heterostructures have been firstly constructed by the high-capacity MoS3 and high-conductive N-doped carbon to co-decorate the Cu2 S hollow nanospheres. During the heterostructure, the middle N-doped carbon layer as the linker facilitates the uniform deposition of MoS3 and enhances the structural stability and electronic conductivity. The popular hollow/porous structures largely restrain the big volume changes of active materials. Due to the cooperative effect of three components, the new Cu2 S@NC@MoS3 heterostructures with dual heterogenous interfaces and small voltage hysteresis for sodium ion storage display a high charge capacity (545 mAh g-1 for 200 cycles at 0.5 A g-1 ), excellent rate capability (424 mAh g-1 at 15 A g-1 ) and ultra-long cyclic life (491 mAh g-1 for 2000 cycles at 3 A g-1 ). Except for the performance test, the reaction mechanism, kinetics analysis, and theoretical calculation have been performed to explain the reason of excellent electrochemical performance of Cu2 S@NC@MoS3 . The rich active sites and rapid Na+ diffusion kinetics of this ternary heterostructure is beneficial to the high efficient sodium storage. The assembled full cell matched with Na3 V2 (PO4 )3 @rGO cathode likewise displays remarkable electrochemical properties. The outstanding sodium storage performances of Cu2 S@NC@MoS3 heterostructures indicate the potential applications in energy storage fields.

The recombinant subunit vaccine encapsulated by alginate-chitosan microsphere enhances the immune effect against Micropterus salmoides rhabdovirus.

The disease caused by Micropterus salmoides rhabdovirus (MSRV) has brought substantial economic losses to the largemouth bass aquaculture industry in China. Vaccination was considered as a potential way to prevent and control this disease. As a kind of sustained and controlled release system, alginate and chitosan microspheres (SA-CS) are widely used in the development of oral vaccination for fish. Here, we prepared a king of alginate-chitosan composite microsphere to encapsulate the second segment of MSRV glycoprotein (G2 protein) and then evaluated the immune effect of the microsphere vaccine on largemouth bass. Largemouth bass were vaccinated via intragastric immunization by different treatments (PBS, SA-CS, G2 and SA-CS-G2). The results showed that a stronger immune response including serum antibody levels, immune-related physiological indexes (acid phosphatase, alkaline phosphatase, superoxide dismutase and total antioxidant capacity) and the expression of immune-related gene (IgM、IL-8、IL-1ß、CD4、TGF-ß、TNF-α) can be induced obviously with SA-CS-G2 groups compared with G2 groups when fish were vaccinated. Furthermore, fish were injected with a lethal dose of MSRV after immunization for 28 days, and the highest relative percentage survival (54.8%) was observed in SA-CS-G2 group (40 µg per fish), which is significantly higher than that of G2 group (25.8%). This study showed that alginate-chitosan microspheres as the vaccine carrier can effectively improve the immune effect of oral vaccination and induce better immune protection effect against MSRV infection.

Antigenic epitope screening and functional modification of mannose enhance the efficacy of largemouth bass virus subunit vaccines.

Major capsid protein (MCP) can be used as a subunit vaccine against largemouth bass virus (LMBV). However, subunit vaccines usually have low immunogenicity. Here, to identify the major immunogenicity determinant region of the MCP gene, we truncated the MCP of the LMBV gene into four parts (MCP-1, MCP-2, MCP-3 and MCP-4). Enzyme-linked immunosorbent assay (ELISA) was used to identify the antigenicity of these four truncated MCP proteins. Then, the highly antigenic truncated protein was modified with mannose and connected with functionalized single-walled carbon nanotubes (SWCNTs) as carriers. Largemouth basses were immunized by bath immersion, challenged with LMBV on the 28th day after immunization and evaluated for related immune indicators. The results indicated that the MCP-2 protein could induce a higher antibody titre than the other truncated MCP proteins. We found that the levels of immune-related genes (TNF-α, CD40, IgM, IFNγ and IL-10) in the spleen and kidney were significantly increased in the MCP-2 and MCP-2-Man groups. ELISA results showed that the antibody content in the serum increased significantly in the MCP-2 group 7 days post-vaccination and increased with days in all the vaccinated groups, with the highest observed on the 21st day. Notably, the MCP-2-Man vaccine (10 mg L-1 ) showed durability of immunoprotection efficacy that could protect largemouth basses from LMBV challenge, and the immune protection rate reached 78.94%. These results suggest that MCP-2 might be the major immunogenicity determinant region of LMBV and that the mannose-modified MCP-2 vaccine can induce stronger adaptive immune responses.

Willow-Leaf-Like ZnSe@N-Doped Carbon Nanoarchitecture as a Stable and High-Performance Anode Material for Sodium-Ion and Potassium-Ion Batteries.

ZnSe is regarded as a promising anode material for energy storage due to its high theoretical capacity and environment friendliness. Nevertheless, it is still a significant challenge to obtain superior electrode materials with stable performance owing to the serious volume change and aggregation upon cycling. Herein, a willow-leaf-like nitrogen-doped carbon-coated ZnSe (ZnSe@NC) composite synthesized through facile solvothermal and subsequent selenization process is beneficial to expose more active sites and facilitate the fast electron/ion transmission. These merits significantly enhance the electrochemical performances of ZnSe@NC for sodium-ion batteries (SIBs) and potassium-ion batteries (PIBs). The obtained ZnSe@NC exhibits outstanding rate performance (440.3 mAh g-1 at 0.1 A g-1 and 144.4 mAh g-1 at 10 A g-1 ) and ultralong cycle stability (242.2 mAh g-1 at 8.0 A g-1 even after 3200 cycles) for SIBs. It is noted that 106.5 mAh g-1 can be retained after 550 cycles and 71.4 mAh g-1 is still remained after 1500 cycles at 200 mA g-1 when applied as anode for PIBs, indicating good cycle stability of the electrode. The possible electrochemical mechanism and the ionic diffusion kinetics of the ZnSe@NC are investigated using ex situ X-ray diffraction, high-resolution transmission electron microscopy, and a series of electrochemical analyses.

Subsequent monitoring of ferric ion and ascorbic acid using graphdiyne quantum dots-based optical sensors.

Graphdiyne (GDY) as an emerging carbon nanomaterial has attracted increasing attention because of its uniformly distributed pores, highly π-conjugated, and tunable electronic properties. These excellent characteristics have been widely explored in the fields of energy storage and catalysts, yet there is no report on the development of sensors based on the outstanding optical property of GDY. In this paper, a new sensing mechanism is reported built upon the synergistic effect between inner filter effect and photoinduced electron transfer. We constructed a novel nanosensor based upon the newly-synthesized nanomaterial and demonstrated a sensitive and selective detection for both Fe3+ ion and ascorbic acid, enabling the measurements in real clinical samples. For the first time fluorescent graphdiyne oxide quantum dots (GDYO-QDs) were prepared using a facile ultrasonic protocol and they were characterized with a range of techniques, showing a strong blue-green emission with 14.6% quantum yield. The emission is quenched efficiently by Fe3+ and recovered by ascorbic acid (AA). We have fabricated an off/on fluorescent nanosensors based on this unique property. The nanosensors are able to detect Fe3+ as low as 95 nmol L-1 with a promising dynamic range from 0.25 to 200 µmol L-1. The LOD of AA was 2.5 µmol L-1, with range of 10-500 µmol L-1. It showed a promising capability to detect Fe3+ and AA in serum samples. Graphical abstract.

Interface engineering of Li6.75La3Zr1.75Ta0.25O12via in situ built LiI/ZnLix mixed buffer layer for solid-state lithium metal batteries.

Garnet-type solid-state Li metal batteries (SSLMBs) are viewed as hopeful next-generation batteries due to their high energy density and safety. However, the major obstacle to the development of garnet-type SSLMBs is the lithiophobicity of Li6.75La3Zr1.75Ta0.25O12 (LLZTO), resulting in a large interfacial impedance. Herein, a LiI/ZnLix mixed ion/electron conductive buffer layer is constructed at the interface by an in situ reaction of molten Li metal with ZnI2 film. This mixed buffer layer ensures close contact between the Li metal and garnet, significantly reducing interfacial impedance. As a result, the Li symmetrical cell with the LiI/ZnLix buffer layer shows an interface impedance of 10.3 Ω cm2, much lower than that of the cell with bare LLZTO (1173.4 Ω cm2). The critical current density (CCD) is up to 2.3 mA cm-2, and the symmetric cells present a long cycle life of 2000 h at 0.1 mA cm-2 and 800 h at 1.0 mA cm-2. In addition, the full cells assembled with the LiFePO4 cathode show a capacity of 143.9 mA h g-1 after 200 cycles at 0.5C with a low-capacity decay of 0.021% per cycle. This work reveals a simple, feasible, and practical interface modification strategy for solid-state Li metal batteries.

pH buffer KH2PO4 boosts zinc ion battery performance via facilitating proton reaction of MnO2 cathode.

Zinc-ion batteries (ZIBs) are rapidly emerging as safe, cost-effective, nontoxic, and environmentally friendly energy storage systems. However, mildly acidic electrolytes with depleted protons cannot satisfy the huge demand for proton reactions in MnO2 electrodes and also cause several issues in ZIBs, such as rapidly decaying cycling stability and low reaction kinetics. Herein, we propose a pH-buffering strategy in which KH2PO4 is added to the electrolyte to overcome the problems caused by low proton concentrations. This strategy significantly improves the rate and cycle stability performance of zinc-manganese batteries, delivering a high capacity of 122.5 mAh/g at a high current density of 5 A/g and enabling 9000 cycles at this current density, with a remaining capacity of 70 mAh/g. Ex-situ X-ray diffraction and scanning electron microscopy analyses confirmed the generation/dissolution of Zn3PO4·4H2O and Zn4(OH)6(SO4)·5H2O, byproducts of buffer products and proton reactions. In-situ pH measurements and chemical titration revealed that the pH change during the electrochemical process can be adjusted to a low range of 2.2-2.8, and the phosphate distribution varies with the pH range. Those results reveal that H2PO4- provides protons to the cathode through the chemical balance of HPO42-, HPO42-, and Zn3PO4·4H2O. This study serves as a guide for studying the influences and mechanisms of buffering additives in Zn-MnO2 batteries.

Engineering Au44 Nanoclusters for NIR-II Luminescence Imaging-Guided Photoactivatable Cancer Immunotherapy.

Immunotherapy is an advanced therapeutic strategy of cancer treatment but suffers from the issues of off-target adverse effects, lack of real-time monitoring techniques, and unsustainable response. Herein, an ultrasmall Au nanocluster (NC)-based theranostic probe is designed for second near-infrared window (NIR-II) photoluminescence (PL) imaging-guided phototherapies and photoactivatable cancer immunotherapy. The probe (Au44MBA26-NLG for short) is composed of atomically precise and NIR-II emitting Au44MBA26 NCs (here MBA denotes water-soluble 4-mercaptobenzoic acid) conjugated with immune checkpoint inhibitor 1-cyclohexyl-2-(5H-imidazo[5,1-a]isoindol-5-yl)ethanol (NLG919) via a singlet oxygen (1O2)-cleavable linker. Upon NIR photoirradiation, the Au44MBA26-NLG not only enables NIR-II PL imaging of tumors in deep tissues for guiding tumor therapy but also allows the leverage of photothermal property for cancer photothermal therapy (PTT) and the photogenerated 1O2 for photodynamic therapy (PDT) and releasing NLG919 for cancer immunotherapy. Such a multiple effect modulated by Au44MBA26-NLG prompts the proliferation and activation of effector T cells, upshifts systemic antitumor T-lymphocyte (T cell) immunity, and finally suppresses the growth of both primary and distant tumors in living mice. Overall, this study may provide a promising theranostic nanoplatform toward NIR-II PL imaging-guided phototherapies and photoactivatable cancer immunotherapy.

Ligand engineering of Au44 nanoclusters for NIR-II luminescent and photoacoustic imaging-guided cancer photothermal therapy.

Developing a high-performance noninvasive probe for precise cancer theranostics is very challenging but urgently required. Herein, a novel Au nanoclusters (NCs)-based probe was designed for cancer theranostics via ligand engineering by conjugating photoluminescent (PL) Au44 NCs in the second near-infrared window (NIR-II, 1000-1700 nm) with aromatic photoacoustic (PA)/photothermal molecules through click chemistry. This design bypasses the incompatibility dilemma between photoluminescence (PL) attributes and PA/photothermal properties because the rigidity of the PA/photothermal molecules can lead to aggregation-induced emission (AIE) of the Au(i)-ligand shell of the Au NCs by constraining their nonradiative relaxation. Benefiting from strong NIR-II PL with emissions at 1080 and 1240 nm, high photothermal conversion efficiency (65.12%), low cytotoxicity, appropriate renal clearance, and enhanced permeability and retention (EPR) effect, the as-designed Au NC-based theranostic probe achieves ultradeep NIR-II PL/PA imaging-guided cancer photothermal therapy (PTT). Remarkably, 16 days after photothermal treatment guided by NIR-II PL/PA imaging, mice were all healed without tumor recurrence, while the average life span of the mice in the control groups was only 17-21 days. This study is interesting because it provides a paradigm for designing a metal NC-based theranostics probe, and it may add fundamentally and methodologically to noninvasive imaging-guided disease therapy.

Protective immunity against spring viremia of carp virus by mannose modified chitosan loaded DNA vaccine.

Spring viremia of carp virus (SVCV) usually be considered as one of the serious in viral diseases of aquaculture, and DNA vaccine with novel delivery mechanism or adjuvant has proven to be a promising and effective strategy to control aquatic animal diseases. In this study, the mannose-modified chitosan, a carrier system for vaccine delivery, were used to developed a chitosan-encapsulated DNA vaccine (CS-M-G) against SVCV, then investigated immune response induced by the vaccine. Our results showed that CS-M-G was confirmed the spherical or elliptical with even distribution and ranging from approximately 50 to 150 nm in size, the expression of the antigen gene could still be detected after 21 d post vaccination. The CS-M-G induces the highest antibody levels in the 20 µg dose group which is about 3 times than naked plasmid group at 21 d post vaccination, and still hold a higher level than control group at 28 d post vaccination. On the side, strongest protection with relative percent survival of 62.1% in the 20 µg CS-M-G group, which could produce significantly higher enzyme activities and up-regulated expression of immune-associated genes than control group. Thus, our results indicate that DNA vaccine loaded with mannose-modified chitosan induces strong immune response and provided an effective protection against SVCV infection, may be helpful and extended for developing more aquatic animal vaccines in the future.

Boosting Zn||I2 Battery's Performance by Coating a Zeolite-Based Cation-Exchange Protecting Layer.

HIGHLIGHTS: High-performance Zn||I2 batteries were established by coating zeolite protecting layers. The Zn2+-conductive layer suppresses I3- shuttling, Zn corrosion/dendrite growth. The Zeolite-Zn||I2 batteries achieve long lifespan (91.92% capacity retention after 5600 cycles), high coulombic efficiencies (99.76% in average) and large capacity (203-196 mAh g-1 at 0.2 A g-1) simultaneously. The intrinsically safe Zn||I2 battery, one of the leading candidates aiming to replace traditional Pb-acid batteries, is still seriously suffering from short shelf and cycling lifespan, due to the uncontrolled I3--shuttling and dynamic parasitic reactions on Zn anodes. Considering the fact that almost all these detrimental processes terminate on the surfaces of Zn anodes, modifying Zn anodes' surface with protecting layers should be one of the most straightforward and thorough approaches to restrain these processes. Herein, a facile zeolite-based cation-exchange protecting layer is designed to comprehensively suppress the unfavored parasitic reactions on the Zn anodes. The negatively-charged cavities in the zeolite lattice provide highly accessible migration channels for Zn2+, while blocking anions and electrolyte from passing through. This low-cost cation-exchange protecting layer can simultaneously suppress self-discharge, anode corrosion/passivation, and Zn dendrite growth, awarding the Zn||I2 batteries with ultra-long cycle life (91.92% capacity retention after 5600 cycles at 2 A g-1), high coulombic efficiencies (99.76% in average) and large capacity (203-196 mAh g-1 at 0.2 A g-1). This work provides a highly affordable approach for the construction of high-performance Zn-I2 aqueous batteries.

Straightforward preparation of Na2(TiO)SiO4 hollow nanotubes as anodes for ultralong cycle life lithium ion battery.

One-dimensional Na2(TiO)SiO4 (SNTO) nanotubes have been successfully synthesized by a straightforward hydrothermal method with the assistance of cetyltetramethyl ammonium bromide (CTAB). Herein, the influence of the Si/Ti ratio on the morphology or composition of SNTO hollow nanotubes has been investigated, and the result shows that the optimum molar ratio of the optimal morphology is 1 : 1. The prepared samples were first applied as anodes in lithium ion batteries (LIBs) for the time being and superior rate capability, ultralong and stable cycling lifespan performance were obtained. The facile and uniquely designed one-dimensional SNTO nanotube electrodes delivered a high reversible capacity of 121.9 mA h g-1 after 5000 cycles at a high current of 1.0 A g-1 without significant attenuation. The superior electrochemical properties are attributed to their special nanotube structure with a high specific surface area, which could shorten the ion/electron transport pathway, and increase the number of active sites and the contact area between the electrolyte and active electrodes. Meanwhile, the kinetic analysis of the electrochemical behaviors of SNTO hollow nanotube electrodes was carried out by performing calculations using cyclic voltammograms recorded at different scan rates, and the results showed that the obtained reversible capacity is mainly due to the capacitive contribution. This work expands the types of anode materials for LIBs, which will further promote the development of LIBs.

Establishing High-Performance Quasi-Solid Zn/I2 Batteries with Alginate-Based Hydrogel Electrolytes.

Zinc-iodine (Zn/I2) batteries are recognized as a kind of leading candidate for large-scale energy storage systems, owing to the high-capacity dissolution-deposition reactions on both electrodes. Nevertheless, the lifespan of Zn/I2 batteries is severely limited by the uncontrolled shuttling of triiodide ions (I3-) and unfavorable side reactions on Zn anodes. Herein, an alginate-based polyanionic hydrogel electrolyte is designed and synthesized by ion exchange and Zn2+-induced cross-linking. The immobile, negatively charged polyanionic chains on the hydrogel skeleton effectively block I3- from shuttling, while simultaneously transporting cations that are indispensable for battery chemistry. Moreover, this hydrogel can also enhance the cycling durability of Zn anodes by alleviating Zn's dendritic growth and corrosion reactions, due to the homogenized Zn2+ flux and reduced interfacial contact between free water and metallic Zn. Consequently, this alginate-based hydrogel electrolyte enables stable Zn plating/stripping for over 600 h at 2 mA cm-2 and 2 mAh cm-2 (corresponding to 10% depth of discharge). Serving as an electrolyte for Zn/I2 full batteries, this hydrogel helps the battery to achieve a high capacity of 183.4 mAh g-1 (capacity retention = 97.6%) after even 200 cycles at 0.2 A g-1, 77.4% higher than that of the traditional ZnSO4 aqueous counterpart (residual capacity = 41.5 mAh g-1). This work indicates the promising potential of electrolyte design on the performance improvement of aqueous Zn/I2 batteries.

SnS2 Nanosheets with RGO Modification as High-Performance Anode Materials for Na-Ion and K-Ion Batteries.

To date, the fabrication of advanced anode materials that can accommodate both Na+ and K+ storage is still very challenging. Herein, we developed a facile solvothermal and subsequent annealing process to synthesize SnS2/RGO composite, in which SnS2 nanosheets are bonded on RGO, and investigated their potential as anodes for Na+ and K+ storage. When used as an anode in SIBs, the as-prepared SnS2/RGO displays preeminent performance (581 mAh g-1 at 0.5 A g-1 after 80 cycles), which is a significant improvement compared with pure SnS2. More encouragingly, SnS2/RGO also exhibits good cycling stability (130 mAh g-1 at 0.3 A g-1 after 300 cycles) and excellent rate capability (520.8 mAh g-1 at 0.05 A g-1 and 281.4 mAh g-1 at 0.5 A g-1) when used as anode for PIBs. The well-engineered structure not only guarantees the fast electrode reaction kinetics, but also ensures superior pseudocapacitance contribution during repeated cycles, which has been proved by kinetic analysis.

Improved electrochemical performance of 2D accordion-like MnV2O6 nanosheets as anode materials for Li-ion batteries.

MnV2O6 is a promising anode material for lithium ion batteries with high theoretical specific capacity, abundant reserves and inexpensive constituent elements. However, in the process of lithization and de-lithization, the MnV2O6 anode material will form an amorphous phase, leading to collapse of its original layered structure; this greatly decreases its lithium storage capacity and specific capacity and affects its long-term cycle performance. In this study, 2D accordion-like MnV2O6 nanosheets with Co-doping are obtained via a hydrothermal route. The cobalt ions partially replace the positions of the manganese ions, and the emergence of Co3+ ions is inferred to induce the formation of a built-in electric field in the electrode to enhance the electrochemical behaviour of MnV2O6, presenting a high capacity of 1005.9 mA h g-1 after hundreds of cycles. The capacitive contribution to the total capacity is investigated to obtain insight into the kinetic analysis of its electrochemical behaviour. This study sheds light on an effective strategy to obtain excellent electrochemical behavior of MnV2O6-based materials and other transition metal oxides as electrodes for lithium storage.

Fe3O4 Hollow Nanosphere-Coated Spherical-Graphite Composites: A High-Rate Capacity and Ultra-Long Cycle Life Anode Material for Lithium Ion Batteries.

The spherical-graphite/Fe3O4 composite has been successfully fabricated by a simple two-step synthesis strategy. The oxygenous functional groups between spherical-graphite and Fe3O4 benefit the loading of hollow Fe3O4 nanospheres. All of the composites as anodes for half cells show higher lithium storage capacities and better rate performances in comparison with spherical-graphite. The composite containing 39 wt% of hollow Fe3O4 nanospheres exhibits a high reversible capacity of 806 mAh g-1 up to 200 cycles at 0.5 A g-1. When cycled at a higher current density of 2 A g-1, a high charge capacity of 510 mAh g-1 can be sustained, even after 1000 long cycles. Meanwhile, its electrochemical performance for full cells was investigated. When matching with LiCoO2 cathode, its specific capacity can remain at 137 mAh g-1 after 100 cycles. The outstanding lithium storage performance of the spherical-graphite/Fe3O4 composite may depend on the surface modification of high capacity hollow Fe3O4 nanospheres. This work indicates that the spherical-graphite/Fe3O4 composite is one kind of prospective anode material in future energy storage fields.

Nano-SiO2 coating enabled uniform Na stripping/plating for dendrite-free and long-life sodium metal batteries.

Metallic sodium, which has a suitable redox potential and high theoretical capacity, is regarded as an ideal anode material for rechargeable Na metal batteries. However, dendrite growth on sodium metal during cycling has seriously restricted its practical applications. Herein, we employed a low-cost and facile brushing method to fabricate a porous nano-SiO2 coating, which can induce a relatively uniform distribution of Na+ flux and suppress the growth of Na dendrites. The nano-SiO2 coating with high porosity can decrease the Na stripping/plating overpotential (<50 mV) over 400 cycles at 5 mA cm-2. Moreover, when coupled with a Na3V2(PO4)3 (NVP) cathode, the Na with SiO2 coating (Na@SiO2) composite anode shows a favorable suitability in a full cell. Compared with the one with a bare Na anode, the full cell with the Na@SiO2 anode delivers a 27.8% higher discharge capacity (94.6 vs. 74 mA h g-1 at 1C) after 1000 cycles.

Three-Dimensional SnS Decorated Carbon Nano-Networks as Anode Materials for Lithium and Sodium Ion Batteries.

The three-dimensional (3D) SnS decorated carbon nano-networks (SnS@C) were synthesized via a facile two-step method of freeze-drying combined with post-heat treatment. The lithium and sodium storage performances of above composites acting as anode materials were investigated. As anode materials for lithium ion batteries, a high reversible capacity of 780 mAh·g-1 for SnS@C composites can be obtained at 100 mA·g-1 after 100 cycles. Even cycled at a high current density of 2 A·g-1, the reversible capacity of this composite can be maintained at 610 mAh·g-1 after 1000 cycles. The initial charge capacity for sodium ion batteries can reach 333 mAh·g-1, and it retains a reversible capacity of 186 mAh·g-1 at 100 mA·g-1 after 100 cycles. The good lithium or sodium storage performances are likely attributed to the synergistic effects of the conductive carbon nano-networks and small SnS nanoparticles.

Recycled Carbon Fiber-Supported Polyaniline/Manganese Dioxide Prepared via One-Step Electrodeposition for Flexible Supercapacitor Integrated Electrodes.

The exploration of multifunctional electrode materials has been a hotspot for the development of high-performance supercapacitors. We have used carbon fiber plates recovered from construction waste to prepare high-quality flexible carbon fiber materials by pyrolysis of epoxy resin. The as-prepared recycled carbon fiber has a diameter of 8 µm and is the perfect substrate material for flexible electrode materials. Furthermore, polyaniline and manganese dioxide are uniformly deposited on the recycled carbon fiber by one-step electrodeposition to form an active film. The recycled carbon fiber/polyaniline/MnO2 composite shows an excellent specific capacitance of 475.1 F·g-1 and capacitance retention of 86.1% after 5000 GCD cycles at 1 A·g-1 in 1 M Na2SO4 electrolyte. The composites optimized for electrodeposition time have more electroactive sites, faster ions and electron transfer, structural stability and higher conductivity, endowing the composites promising application prospect.