Jifu Shi

All-Solid-State Lithium Organic Battery with Composite Polymer Electrolyte and Pillar[5]quinone Cathode

The cathode capacity of common lithium ion batteries (LIBs) using inorganic electrodes and liquid electrolytes must be further improved. Alternatively, all-solid-state lithium batteries comprising the electrode of organic compounds can offer much higher capacity. Herein, we successfully fabricated an all-solid-state lithium battery based on organic pillar[5]quinone (C35H20O10) cathode and composite polymer electrolyte (CPE). The poly(methacrylate) (PMA)/poly(ethylene glycol) (PEG)-LiClO4-3 wt % SiO2 CPE has an optimum ionic conductivity of 0.26 mS cm(-1) at room temperature. Furthermore, pillar[5]quinine cathode in all-solid-state battery rendered an average operation voltage of ∼2.6 V and a high initial capacity of 418 mAh g(-1) with a stable cyclability (94.7% capacity retention after 50 cycles at 0.2C rate) through the reversible redox reactions of enolate/quinonid carbonyl groups, showing favorable prospect for the device application with high capacity.

A Soft Hydrogen Storage Material: Poly(Methyl Acrylate)‐Confined Ammonia Borane with Controllable Dehydrogenation

2010 WILEY-VCH Verlag Gm Highly efficient and convenient hydrogen storage materials/ technology are still the main challenge for today’s development of hydrogen economy. Ammonia borane (NH3BH3, AB) has recently attracted great interests as promising hydrogen storage media because of its low molecular weight (30.7 g mol ) and high gravimetric hydrogen capacity (19.6wt%). Neat AB can release H2 by stepwise thermolysis reaction. However, the practical application of AB is still embarrassed by its slow thermal kinetics below 100 8C and the detrimental volatile byproducts such as borazine (HNBH)3 and diborane (B2H6). To overcome these barriers, great efforts have been devoted to the use of nanoscaffolds, transition metals, ionic liquids, and additives. Despite considerable achievement, new approaches that are easier to operate andmore practicable remain to be developed. Furthermore, the hygroscopic properties and water solubility of borohydrides will negatively affect their thermolysis performance; these effects have hardly been taken into account until now. Therefore, a new AB-based systemwith water resistance and favorable dehydrogenating properties is required to promote the applicable value of AB. Herein, we report a water-resistant system of AB confined in poly(methyl acrylate) (PMA) that efficiently lowers the H2-release temperature and suppresses the generation of detrimental boracic impurities, which should shed light onto the application of AB as an attractive hydrogen-storage material. The PMA-AB composite was synthesized through a simple solution-blending process (Experimental section). The products with 20 and 80mg AB in 100mg PMA were denoted as PAB20 and PAB80, respectively. At ambient conditions, commercial AB is a white powder (Fig. 1A), while the prepared PAB20 is a semitransparent rubbery material (Fig. 1B). Solid PAB20 is soft and flexible and can also be prepared in form of a transparent film by directly evaporating the blend solution onto a flat glass (Fig. S1, Supporting Information). Notably, the obtained PAB80 solid is opaque (Fig. 2C) and soft but a little tougher than PAB20. The X-ray diffraction (XRD) patterns of commercial AB and polymeric composites are shown in Figure 1D. The tested commercial AB shows a typical polycrystalline structure with tetragonal lattice symmetry. No obvious crystalline peaks but a broad peak between 208 and 258 is detected in the XRD pattern of PAB20 (Fig. 1D, trace b), demonstrating an amorphous structure. However, the characteristic diffraction peaks of AB emerge in trace (c) for PAB80, which indicates that partial AB exists in the form of a crystalline phase in the polymeric composite with higher AB content. A possible reason for this observation is that the amount of AB molecules in the PMA texture has reached/ exceeded the dispersive saturation under this concentration, which leads to a partial recrystallization of AB during the preparation process.

Quasi-Solid-State Dye-Sensitized Solar Cells with Polymer Gel Electrolyte and Triphenylamine-Based Organic Dyes

We report on the application of a poly(methyl acrylate)/poly(ethylene glycol)-based polymer gel electrolyte and triphenylamine-based metal-free organic dyes in quasi-solid-state dye-sensitized solar cells. The poly(methyl acrylate)/poly(ethylene glycol) hybrid is beneficial to the entrapment of a large volume of liquid electrolyte. At 25 degrees C, the ionic conductivity and the triiodide ionic diffusion constant of the as-prepared polymer gel electrolyte are 2.1 mS cm(-1) and 2.3 x 10(-6) cm(2) s(-1), respectively. The quasi-solid-state solar cell sensitized by triphenylamine-based dyes attains an overall energy conversion efficiency of 5.76% at a light intensity of 30 mW cm(-2). The presence of poly(ethylene glycol) in the electrolyte obviously increases the conductivity and energy conversion efficiency compared to that without poly(ethylene glycol).

Synthesis of thermochromic W-doped VO 2 (M/R) nanopowders by a simple solution-based process

Thermochromic W-doped VO2 nanopowders were prepared by a novel and simple solution-based method and characterized by a variety of techniques. We mainly investigated the effect of tungsten dopant on the structural properties and phase transition of V1-xWxO2. The as-obtained nanopowders with tungsten content of ≤ 2.5 at% can be readily indexed as monoclinic VO2 (M) while that of 3 at% assigned into the rutile VO2 (R). The valence state of tungsten in the nanopowders is +6. TEM and XRD results show that the substitution of W atom for V in VO2 results in a decrease of the d space of the (011) plane. The phase transition temperature is determined by differential scanning calorimetry (DSC). It is found, for the first time, that the reduction of transition temperature reaches to 17 K per 1 at% of Wdoping with the tungsten extents of ≤1 at%, but only 9.5 K per 1 at% with the tungsten extents of >1 at%. The reason of this arises from the difficulty of the formation of V3+-W4+ and V3+-W6+ pairs by the increasing of Wions doping in the V1-xWxO2 system.

Flower-Like Molybdenum Disulfide for Polarity-Triggered Accumulation/Release of Small Molecules

Flower-like molybdenum disulfide (MoS2) with rich edge sites has been prepared by the hydrothermal method. The edge sites possess polarity due to the noncentrosymmetric Mo-S on exposed (100) facets and thus show a strong electrostatic attraction toward polar species. The flower-like MoS2 can be used as small-molecule carriers for the model drug, Rhodamine B (RhB). The results prove that flower-like MoS2 have fast adsorption kinetics and perform a switchable accumulation/release with response to the solvent polarity. An outstanding reusability can be found in flower-like MoS2 due to little cargo retention, and the recycle of adsorption can be repeated 100 times with above 88.5% of the adsorption capacity retained. The flower-like MoS2 with solvent polarity-triggered loading/release can be extended to controlled release and color switch of display.

All-solid-state nanocomposite electrolytes composed of an ionic polymer with polar groups and surface-modified SiO2 nanoparticles for dye-sensitized solar cells

Solid-state electrolytes based on ionic polymer (IP)–SiO2 nanocomposite are prepared for dye-sensitized solar cells (DSCs). An IP with a cationic main chain and polar ester and carbonyl groups is synthesized from 2,3-dichloropropionic acid methyl ester and N,N′-carbonyldiimidazole. SiO2 nanoparticles are chemically modified by silane coupling agents KH550 and KH570. The polar groups in the IP and on the surface of the modified SiO2 can facilitate the ionization of iodide in the electrolyte and increase the number of charge carriers. Moreover, according to the principle of ‘like dissolves like’, SiO2 modified by polar groups can be compatible with the IP and yield a long-term stability for the electrolyte. Eventually, the solid-state electrolyte containing IP and modified SiO2 achieves a high conductivity of 3.05 mS cm−1. The all-solid-state DSCs with the composite electrolyte have favorable stability and photo-to-current conversion efficiencies of 5.03% at 30 mW cm−2 and 4.86% at 100 mW cm−2.

A superhydrophobic solar selective absorber used in a flat plate solar collector

A new kind of superhydrophobic (SH) solar selective absorber (SSA) used in a low-temperature flat plate solar collector is proposed. Getting rid of the glass cover can improve the performance of the flat plate solar collector. SSA with a SH coating can maintain the efficiency in a practical outdoor working environment. The SH coating can be made by a simple Sol–Gel method; the water contact angle of SH SSA can reach up to 157° and the sliding angle is less than 2°. The self-cleaning of SH SSA can be realized by rainwater or natural wind. The solar absorptance of SH SSA is still 89.46% after treating in a neutral salt spray for 48 h, which indicates that SH SSA has good corrosion resistance and is suitable to the outdoor environment. Thermal performance tests show that the flat plat solar collector with SH SSA has excellent thermal performance for low-temperature application.

High performance VO2 thin films fabricated by room-temperature reactive magnetron sputtering and rapid thermal annealing

The VOx thin films are successfully prepared on glass substrate by reactive magnetron sputtering at room-temperature, and subsequently annealed by rapid thermal annealing system in N2 from 0.5Pa to 10000Pa. The effects of annealing pressure on the optical performance and phase transition temperature (Tc) of VOx thin films are systematically investigated. The results show that the VOx thin films exhibit good performance with Tlum of 28.17%, ΔTsol of 12.69%, and Tc of 42. The annealing pressure had an obvious influence on the grain size, which can be attributed to light scattering effects by gas molecule. Compared with oxygen vacancy defects, the grain size plays a decisive role in the regulation of Tc. The restricting the growth of grain can be reduced the Tc, and a little deterioration effect on optical performance can be observed. In addition, the method in this paper not only depressed the Tc, but also simplified the process and improved efficiency, which will provide guidance for the preparation and application of VOx thin films.

Imprinted MoS2 achieve highly efficient self-separative molecule extraction

Imprinting is a biological process where a young animal acquires several of its behavioural characteristics from its parent and then follows them around and is called filial imprinting. However, imprinting can implicitly be inside the materials that possess a suitable affinity to integrate themselves with the surrounding liquid environment. In this research, an example of imprinting in molybdenum disulfide (MoS2) nanosheets was demonstrated. The as-prepared MoS2 containing a polar edge and low-polar plane faces on its flower-like morphology give it an imprinting ability to adhere to water or n-hexane. Therefore, imprinted MoS2 tends to retain the phase of the imprinting solvent, which is called solvent identification. More interestingly, imprinted MoS2 can in addition fulfill a highly efficient heterophasic extraction of rhodamine B (RhB) from water to n-hexane or lauric acid from n-hexane to water in seconds. At the same time, imprinted MoS2 solvent identification exhibits rapid self-separation after shaking, which avoids tedious centrifugation and filtration in a separation-purification process and makes it more convenient.

Dye-sensitized solar cell module realized photovoltaic and photothermal highly efficient conversion via three-dimensional printing technology

Three-dimensional (3D) printing technology is employed to improve the photovoltaic and photothermal conversion efficiency of dye-sensitized solar cell (DSC) module. The 3D-printed concentrator is optically designed and improves the photovoltaic efficiency of the DSC module from 5.48% to 7.03%. Additionally, with the 3D-printed microfluidic device serving as water cooling, the temperature of the DSC can be effectively controlled, which is beneficial for keeping a high photovoltaic conversion efficiency for DSC module. Moreover, the 3D-printed microfluidic device can realize photothermal conversion with an instantaneous photothermal efficiency of 42.1%. The integrated device realizes a total photovoltaic and photothermal conversion efficiency of 49% at the optimal working condition.