Different-grain-sized boehmite nanoparticles for stable all-solid-state lithium metal batteries.

PEO is one of the common composite polymer electrolyte vehicles; however, the presence of crystalline phase at room temperature, high interface impedance, and low oxidation resistance (<4.0 V) limit its application in stable all-solid-state lithium metal batteries. Herein, we designed a PEO-based solid polymer electrolyte (SPE) by adding boehmite nanoparticles to address the above-mentioned issues. Different-grain-sized boehmite nanoparticles were synthesized by adjusting the hydrothermal temperature. Moreover, the impacts of these distinct grain-sized boehmite nanoparticles used to fabricate boehmite/PEO polymer electrolytes (BPEs) on the performance of all-solid-state lithium metal batteries were investigated. It was found that with the increase in boehmite's grain size, BPEs show better performance. The best BPE exhibited an improved Li+ transference number (0.59), high ionic conductivity (1.25 × 10-4 S m-1), and wide electrochemical window (∼4.5 V) at 60 °C. The assembled lithium symmetric battery can stably undergo 500 hours of lithium plating/stripping at 0.1 mA cm-2. At the same time, the LiFePO4/BPE/Li battery exhibits excellent cycling stability after 100 cycles at 0.5C. This reasonable design strategy with a superior capacity retention rate (86%) demonstrates great potential in achieving high ionic conductivity and good interface stability for all-solid-state lithium metal batteries simultaneously.

Class of Boehmite/Polyacrylonitrile Membranes with Different Thermal Shutdown Temperatures for High-Performance Lithium-Ion Batteries.

Nowadays, lithium-ion batteries are required to have a higher energy density and safety because of their wide applications. Current commercial separators have poor wettability and thermal stability, which significantly impact the performance and safety of batteries. In this study, a class of boehmite particles with different grain sizes was synthesized by adjusting hydrothermal temperatures and used to fabricate boehmite/polyacrylonitrile (BM/PAN) membranes. All of these BM/PAN membranes can not only maintain excellent thermal dimensional stability above 200 °C but also have good electrolyte wettability and high porosity. More interestingly, the BM/PAN membranes' thermal shutdown temperature can be adjusted by changing the grain size of boehmite particles. The lithium-ion batteries assembled with BM/PAN separators exhibit different thermal stability phenomena at 150 °C and have excellent rate performance and cycle stability at room temperature. After 120 cycles at 1C, the LiFePO4 half-cell assembled by the best BM/PAN separator has almost unchanged discharge capacity, whereas the capacity retention of Celgard 2325 is only about 85%. Meanwhile, the NCM523 half-cell assembled with the best BM/PAN separator shows superb cycle stability after 500 cycles at 8C, with a capacity retention of 79% compared with 56% for Celgard 2325.

Synthesis of an aromatic N-heterocycle derived from biomass and its use as a polymer feedstock.

Aromatic N-heterocyclic compounds are very important chemicals, which are currently produced mostly from petroleum. Here we report that a pyridazine-based compound 6-(4-hydroxy-3-methoxyphenyl)pyridazin-3(2H)-one (GSPZ) can be efficiently synthesized by the Friedel-Crafts reaction of guaiacol and succinic anhydride, both of which can be derived from biomass. GSPZ is then treated with bio-based epichlorohydrin to prepare the epoxy resin precursor GSPZ-EP. With 4,4'-diaminodiphenylmethane as curing agent, GSPZ-EP possesses higher glass transition temperature (187 oC vs. 173 oC) and shows a 140%, 70 and 93% increase in char yield (in N2), storage modulus (30 oC) and Young's modulus, respectively when compared with a standard petroleum-based bisphenol A epoxy resin. Moreover, the cured GSPZ-EP shows good intrinsic flame retardancy properties and is very close to the V-0 rating of UL-94 test. This work opens the door for production of aromatic N-heterocyclic compounds, which can be derived from biomass and employed to construct high performance polymers.

Colorimetric determination of glutathione by using a nanohybrid composed of manganese dioxide and carbon dots.

A kind of single-layer carbon based dots (CDs) with abundant carboxyl functional groups was hybridized with manganese dioxide (MnO2). The resulting nanohybrid is stable and can be well dispersed in water. MnO2 is capable of oxidizing the substrate 3,3'5,5'-tetramethylbenzidine (TMB) to form a blue product whose absorption (peaking at 655 nm) fades in the presence of glutathione (GSH). A sensitive and selective colorimetric GSH assay was worked out that has a linear response in the 10 to 0.1 µM GSH concentration range, with a 0.095 µM detection limit. The method was applied to the determination of GSH in spiked fetal calf serum where it gave excellent recoveries. Graphical abstract Schematic of the preparation of a nanohybrid composed of manganese dioxide and carbon based dots (MnO2/CDs). They can be used for the colorimetric detection of glutathione (GSH) based on the color change of 3,3'5,5'-tetramethylbenzidine (TMB).

A novel smart supramolecular organic gelator exhibiting dual-channel responsive sensing behaviours towards fluoride ion via gel-gel states.

A novel smart supramolecular organic gelator G-16 containing anion and metal-coordination ability has been designed and synthesized. It shows excellent and robust gelation capability as a strong blue fluorescent supramolecular organic gel OG in DMF. Addition of Zn(2+) produced Zn(2+)-coordinated supramolecular metallogel OG-Zn. Organic gel OG and organometallic gel OG-Zn exhibited efficient and different sensing behaviors towards fluoride ion due to the variation in self-assembling nature. Supramolecular metallogel OG-Zn displayed specific selectivity for fluoride ion and formed OG-Zn-F with dramatic color change from blue to blue green in solution and gel to gel states. Furthermore after directly addition of fluoride into OG produced fluoride containing organic gel OG-F with drastically modulation in color from blue to greenish yellow fluorescence via strong aggregation-induced emission (AIE) property. A number of experiments were conducted such as FTIR, (1)H NMR, and UV/Vis spectroscopies, XRD, SEM and rheology. These results revealed that the driving forces involved in self-assembly of OG, OG-Zn, OG-Zn-F and OG-F were hydrogen bonding, metal coordination, π-π interactions, and van der Waal forces. In contrast to the most anion responsive gels, particularly fluoride ion responsive gels showed gel-sol state transition on stimulation by anions, the gel state of OG and OG-Zn did not show any gel-to-sol transition during the whole F(-) response process.

An interwoven network of MnO2 nanowires and carbon nanotubes as the anode for bendable lithium-ion batteries.

A porous interwoven network is synthesized, consisting of ultralong MnO2 nanowires and multi-walled carbon nanotubes (MWCNTs). Serving as the anode for a lithium-ion battery, this nanocomposite demonstrates excellent performance due to the synergistic integration of these two 1D materials. Taking advantage of the excellent flexibility and strength of this MnO2-MWCNT network, a full, bendable battery is made that offers high capacity, cycling stability, and low cost.

Controllable fabrication of zinc borate hierarchical nanostructure on brucite surface for enhanced mechanical properties and flame retardant behaviors.

A novel and efficient halogen-free composite flame retardant (CFR) consisting of a brucite core and a fine zinc borate [Zn6O(OH)(BO3)3] hierarchical nanostructure shell was designed and synthesized via a facile nanoengineering route. It had been demonstrated that this unique hybrid structure possessed a high BET specific surface area (65 m(2)/g) and could significantly enhance the interfacial interaction when mixing with ethylene-vinyl acetate (EVA). This improved the transfer of stress between CFR particles and EVA matrix and increased the viscosity of EVA/EVA blends, which was beneficial for droplet inhibition and char forming. The mechanical properties and flammability behaviors of the EVA/CFR blends had been compared with the EVA/physical mixture (PM, with the given proportion of brucite and Zn6O(OH)(BO3)3). The mechanical properties of EVA/CFR blends, especially the tensile strength (TS), presented a remarkable increase reaching at least a 20% increment. Meanwhile, with the same 45 wt % of fillers, the EVA/CFR formulation could achieve a limiting oxygen index (LOI) value of 33 (37.5 % higher than that of EVA/PM blends) and UL-94 V-0 rating. Moreover, the heat release rate (HRR), peak heat release rate (PHRR), total heat released (THR), smoke production rate (SPR) and mass loss rate (MLR) were considerably reduced, especially PHRR and SPR for EVA/CFR blends were reduced to 32%. According to this study, the design of fine structure might pave the way for the future development of halogen-free flame retardants combining both enhanced mechanical properties and excellent flame retardant behaviors.

2D single- or double-layered vanadium oxide nanosheet assembled 3D microflowers: controlled synthesis, growth mechanism, and applications.

A facile one-pot solvent-thermal method was developed to synthesize a unique 3D microflower structure assembled from single- or double-layered 2D nanosheets of V4O9 (F-VO). Simply by controlling the precursor concentration, yolk-shelled V4O9 (YS-VO) or bulk V4O9 (B-VO) can be produced instead. The precursor-concentration dependent growth mechanism is proposed. The exceptional catalytic/electrochemical properties and large specific surface area of F-VO promise a wide range of applications. As a proof-of-concept demonstration, we investigate its use in high-performance supercapacitors (~392 F g(-1)), and for sensitive detection of H2O2 (with a low detection limit of ~0.1 µM) and methanol (with a low detection limit of ~60 µM). Furthermore, we show that F-VO greatly outperforms its counterparts (YS-VO and B-VO) presumably owing to its unique structure and crystal plane orientation.

Carbon-based dots co-doped with nitrogen and sulfur for high quantum yield and excitation-independent emission.

Helpful elements: A facile bottom-up method using citric acid and L-cysteine as a precursor has been developed to prepare graphene quantum dots (GQDs) co-doped with nitrogen and sulfur. A new type and high density of surface state of GQDs arises, leading to high yields (more than 70 %) and excitation-independent emission. FLQY = fluorescence quantum yield.

Enzymeless multi-sugar fuel cells with high power output based on 3D graphene-Co3O4 hybrid electrodes.

Biofuel cells (BFCs), which use enzymes as catalysts to harvest energy from green and sustainable fuels abundantly producible from biological systems, are promising next-generation energy devices. However, the poor stability and high specificity to only one fuel type of these bio-catalysts largely limits the practical use of current BFCs. In this contribution, we demonstrate a unique fuel cell which, equipped with two identical enzyme-free electrodes based on Co3O4 coated 3D graphene, is able to efficiently harvest electricity from various sweet biofuels (glucose, sucrose, or lactose). Taking advantage of the dual catalytic ability of nanostructured Co3O4 for both glucose oxidation and oxygen reduction as well as the exceptional electrical and structural properties of 3D graphene, our glucose-powered fuel cell, with good long-term stability, offers high open circuit voltage (~1.1 V) and power density output (2.38 ± 0.17 mW cm(-2)).

Template-free bottom-up synthesis of yolk-shell vanadium oxide as high performance cathode for lithium ion batteries.

A template-free strategy is exploited to bottom-up synthesize yolk-shell vanadium oxide through a two-step spontaneous assembly of hydrolytically formed subunits in a one-pot process. The unique structured vanadium pentoxide exhibits excellent cathode performance for lithium ion batteries.

Functionalization of SnO2 photoanode through Mg-doping and TiO2-coating to synergically boost dye-sensitized solar cell performance.

Mg-doped SnO2 with an ultrathin TiO2 coating layer was successfully synthesized through a facile nanoengineering art. Mg-doping and TiO2-coating constructed functionally multi-interfaced SnO2 photoanode for blocking charge recombination and enhancing charge transfer in dye-sensitized solar cells (DSC). The designed nanostructure might play a synergistic effect on the reducing recombination and prolonging the lifetime in DSC device. Consequently, a maximum power conversion efficiency of 4.15% was obtained for solar cells fabricated with the SnO2-based photoelectrode, exhibiting beyond 5-fold improvement in comparison with pure SnO2 nanomterials photoelectrode DSC (0.85%).

Nanoparticle self-assembled hollow TiO2 spheres with well matching visible light scattering for high performance dye-sensitized solar cells.

Submicrometer-sized hollow TiO(2) spheres are directly self-assembled from TiO(2) nanoparticles without using any template or surfactant as a scattering layer for dye-sensitized solar cells, showing good visible light scattering match to significantly improve the photoconversion efficiency.

Direct synthesis of hexagonal Mg(OH)2 nanoplates from natural brucite without dissolution procedure.

A facile, dissolution-free route to direct synthesis of hexagonal magnesium hydroxide nanoplates from natural brucite is reported. Stable brucite undergoes disaggregation into thin nanosheets and subsequent solid-solid transformation in the presence of p-toluene sulfonate, circumventing the threshold of size effect from bulk brucite to Mg(OH)(2) nanoplates.

Luminescent properties of hydrocarbonate-gel derived MgSrAl10Ol7:Eu2+ blue phosphor.

Hydrocarbonate-gel method was applied to prepare MgSrAl10O17:Eu2+ blue phosphors with quasi-spherical morphology. Scanning electron microscope (SEM) and powder X-ray diffraction (XRD) were employed to characterize the resulting products. SEM image showed that the phosphor particles were of quasi-spherical shape with the diameter in the range of 1 approximately 3 microm. X-ray diffraction patterns of the resulting samples displayed pure MgSrAl10O17 phase after annealed at 1270 degrees C for 3 h. The effects of annealing temperature, parameters on crystalline phase evolution and photoluminescence intensities of the resulting phosphor were also studied. Upon excitation with UV irradiation, MgSrAl10O17:Eu2+ shows a strong blue emission at 468 nm corresponding to 4f65d1 --> S7/2 transition of Eu2+, which has potential applications in fluorescent lamps and plasma display panels.