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A gel electrolyte, which comprises polymers to regulate Li+transport and ternary salts to reinforce the interface layer, enables Li+to reversibly deposit on plain Cu foil and the resulting anode-free batteries to work with excellent stability.

Background Self-assembly monolayers (SAMs) had been used widely to tailor the surface properties; and alkanthiols were the most common molecules which have been intensively studied. However, the assembly behavior of amine molecules and the characteristics of the SAMs are not well understood. Method In this study, dodecylamine (DDA) is used as a model molecule to study the self-assembly behavior of amine molecules from HClO4 solution onto an Au(111) surface. The adsorption process and the SAM characteristics are studied via cyclic voltammetry (CV), in-situ surface-enhanced infrared absorption spectroscopy (SEIRAS) and scanning tunneling microscopy (STM). Significant findings The CV spectra show that the current densities of Fe+2/Fe+3 redox reaction decrease slightly after the treatment of DDA, implying the formation of a DDA adlayer. The in-situ SEIRAS spectra demonstrate that the adsorption of DDA performed slowly. These results imply a weak interaction of DDA with the gold surface. The STM observation in the HClO4 solution demonstrates that the adsorbed molecules arranged in an orderly manner, forming a flat-lying orientation. The lift-off orientation commonly found for thiol molecules doesn't occur for the DDA adlayer. On the basis of this study, the self-assembly ability of DDA on a gold surface is confirmed, and a weak DDA-Au interaction is verified.

The mechanism of photocatalytic biomass reforming for H2 production is far from fully understood. This study uses functionalized graphene dots with Pt-cocatalyst to reform cellulose in an alkaline ...

High stability and uniform Li deposition are essential for realizing applications of Li-metal batteries (LMBs). Therefore, a scaffold for polymer electrolytes is designed to achieve highly stable operation and dendrite-free Li deposition. A porous membrane of poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) is synthesized as a scaffold to host a networked poly(ethylene oxide) (PEO)-based solid polymer electrolyte (NSPE) and form a scaffold-hosted electrolyte (NSPE@PF) that exhibits a considerably higher ionic conductivity and Li+-transference number at 30 °C than the reported PEO-based solid polymer electrolytes do. The PVdF-HFP scaffold renders the NSPE@PF electrochemically stable until 5.4 V (vs. Li/Li+). The PVdF-HFP membrane facilitates uniform Li deposition on both Cu- and Li-metal anodes with negligible dendrite growth in both solid-polymer and liquid electrolyte systems. LMBs containing the NSPE@PF exhibit high capacities and a high cycling stability of up to 1100 cycles. The high-dielectric feature of the PVdF-HFP scaffold facilitates counter-ion-pair dissociation and extends the stable voltage range. Its anion-tethering ability minimizes the space-charge zones on the Li-anode surface and suppresses Li-dendrite growth. Moreover, the high mechanical strength of the scaffold facilitates the synthesis of thin and practically usable NSPE@PFs. This scaffold design is promising for realizing LMB applications.

The formation of Li dendrites in Li-metal batteries (LMBs) may lead to a short circuit, causing a fire or an explosion, and consume Li through dead-Li formation and solid-electrolyte interphase (SEI) thickening. Instead of using an artificial SEI, we use a gel polymer electrolyte (GPE) comprising poly(vinylidene fluoride-co-hexafluoro propylene) (PVDF-co-HFP) and poly(2-hydroxyethyl methacrylate) (PHEMA), dual lithium salts, and carbonate solvents to stabilize the SEI and suppress dendrite formation. When incorporated with a separator, the GPE exhibits higher ionic conductivity than liquid electrolytes and has a high Li+-transference number of 0.64. Without adding LiNO3, this GPE allows uniform Li plating/stripping on both Cu- and Li-metal anodes at high currents owing to robust SEI formation and negligible dendrite growth. Full-cell LMBs containing this GPE can deliver high capacities at high discharge rates and present high cycling stability. The high-polarity PVDF-co-HFP facilitates counter-ion dissociation to increase conductivity and tethers an anion to reduce the space-charge region and thus hinder Li-dendrite growth. Moreover, PHEMA closely contacts the metal anodes, which helps suppress solvent reduction and SEI thickening. This GPE is synthesized as a liquid, which coagulates onsite during LMB assembly. This study presents a strategy to advance metal anode technology for realizing LMBs.

The electrolyte pH has been determined to be an important factor that has a direct influence on the formation of film morphologies. Herein, we investigate the effect of electrolyte pH on the formation of nickel oxide (NiOx) films in borate solutions and examine their corresponding electrochromic characteristics. The result shows that the formation of hexa-aquo Ni complexes due to an appropriate electrolyte pH can aid the electrodeposition of NiOx films and produce a film of small grains. Raman and in situ X-ray absorption fine structure (XAFS) measurements indicate that the structure of the NiOx films in their oxidized state is similar to γ-NiOOH, regardless of the electrolyte pH, although the grain size of the films is dependent on the electrolyte pH. The different grain size results in significant differences in electrochromic performance. The film made of small grain size exhibits the best electrochromic performance. The optical contrast of the NiOx film achieved 87%. The coloration efficiency increased by about 50% to 51 cm2/C and the switching time reduced to 5.4 s for bleaching. These results demonstrate the imperative for an appropriate electrolyte pH to enable sustained electrochemical activity, reactive site formation, and functional stability.

In this study, highly efficient dye-sensitized indoor photovoltaics (DSiPVs) are fabricated using quasi-solid-state cobalt-complex electrolytes. PVDF-HFP and PMMA polymers are employed as gelling agents to prepare these gel-type electrolytes. Although such polymers cause slow diffusion of redox couples, the related quasi-solid-state DSiPV cell still outperforms the liquid-state one under artificial-light conditions, which is attributed to the suppressed charge recombination at the photoelectrode/electrolyte interface. By regulating the PVDF-HFP/PMMA ratio and the electrolyte composition, this charge recombination can further be inhibited, thereby creating higher open-circuit voltages. Furthermore, in order to increase short-circuit currents, a cosensitization system and a polymeric catalyst are introduced, which respectively can broaden the light-harvesting region and facilitate interfacial charge transfer at the counter electrode. Consequently, the resultant quasi-solid-state DSiPV cell not only exhibits long-term stability during a 2000 h test, but also achieves a power conversion efficiency (PCE) beyond 25% under 1000-lux fluorescent lighting. The above materials are further utilized to assemble bifacial DSiPVs; the PCE obtained under rear illumination can surpass 91% of the front-illuminated value. Large-area module devices are also demonstrated herein, expressing the ability of powering small electronics in a fluorescent-light environment. This quasi-solid-state DSiPV technology is promising for self-powered electronics in the internet of things.

Highly efficient nanocomposite electrolytes were prepared by mixing the montmorillonite (MMT) clay nanofillers and iodide poly(vinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) gel electrolytes for the purpose of measuring the performance of quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The impacts of different amounts of MMT nanofillers on the ion diffusivity, conductivity of the polymer gel electrolytes (PGEs), and the photovoltaic performance of the cells using the PGEs were evaluated. The results indicated that the use of 5 wt.% MMT markedly increase the ion diffusivity and conductivity of the PVDF-HFP PGE. The introduction of 5 wt.% nanofillers considerably reduced the Warburg diffusion resistance, which made to the high performance of the QS-DSSCs. Cells utilizing 5 wt.% MMT nanofillers were shown to obtain a power conversion efficiency (PCE) (6.77%) higher than that obtained for cells using pure PGEs and identical to that obtained using liquid electrolytes (LEs) (6.77%). The high PCE was a result of an enhance in the current density in the presence of the 5 wt.% MMT nanofillers. The DSSC efficiency was found to maintain 99.9% of its initial value after 194 h of testing at 60℃ under dark environments. The stability of the DSSC using PGEs with the optimal amount of MMT nanofillers was higher than that for the cells using liquid electrolyte and pure PGE.

A new carbon nanotube (CNT) function is proposed herein for dye-sensitized solar cell (DSSC) applications. In this study, single-wall CNT is used as a treating agent to conventional liquid electrol...

Electrochemical water splitting using renewable energy shows promise for the development of sustainable hydrogen production methods. The process requires a highly active electrocatalyst for oxygen evolution to improve the overall water splitting efficiency. The present study showed that oxygen evolution improved dramatically upon the addition of glycine to cobalt phosphate, when the glycine was added to the electrolyte solution during electrodeposition. The functionality of the organic molecules was investigated using in situ UV-vis absorption, in situ X-ray absorption fine structure, and in situ infrared (IR) absorption spectroscopy in the attenuated total reflection mode. The results demonstrated that the glycine molecules assembled cobalt oxide clusters composed of CoO6 (CoOOH) octahedrons a few nanometers in diameter upon the electrodeposition of cobalt catalysts. This suggests that the cobalt-glycine catalyst can decompose water to oxygen gas efficiently, because the number of cobalt oxide clusters increased as active reaction sites upon the addition of glycine molecules.

High-efficiency, stable bifacial dye-sensitized solar cells (DSSCs) are prepared for application under indoor light conditions. A 3-methoxypropionitrile solvent and cobalt redox couples are utilized to prepare the electrolytes. To obtain the best cell performance, the components of the DSSCs, including electrolytes, photoanodes, and counter electrodes (CEs), are regulated. The experimental results indicate that an electrolyte comprising a Co (II/III) ratio of 0.11/0.025 M, 1.2 M 4-tert-butylpyridine, Y123 dye, a CE with the platinum (Pt) layer thickness of 0.16 nm, and a photoanode with titanium dioxide (TiO2) layer thickness of 10 μm (6 μm main layer and 4 μm scattering layer) are the best conditions under which to achieve a high power conversion efficiency. It is also found that the best cells have high recombination resistance at the photoelectrode/electrolyte interface and low charge transfer resistance at the counter electrode/electrolyte interface, which contributes to, respectively, the high current density and open-circuit voltage of the corresponding cells. This DSSC can achieve efficiencies of 22.66%, 23.48%, and 24.52%, respectively, under T5 light illumination of 201.8, 607.8, and 999.6 lx. For fabrication of bifacial DSSCs with a semitransparent property, photoanodes without the TiO2 scattering layer, as well as an ultrathin Pt film, are utilized. The thicknesses of the TiO2 main layer and Pt film are reregulated. This shows that a Pt film with 0.55 nm thickness has both high transmittance (76.01%) and catalytic activity. By using an 8 μm TiO2 main layer, optimal cell efficiencies of 20.65% and 17.31% can be achieved, respectively, for the front-side and back-side illuminations of 200 lx T5 light. The cells are highly stable during a long-term performance test at both 35 and 50 °C.

High-efficiency and stable quasi-solid-state dye-sensitized solar cells (QS-DSSCs) are fabricated using printable polymer gel electrolytes for application under room light conditions. The printable electrolytes are prepared based on 3-methoxypropionitrile liquid electrolytes containing iodide/triiodide redox mediator, polyethylene oxide/polyvinylidene fluoride gelator, and titanium dioxide nanofillers. To obtain the optimal performance of the DSSCs, the composition of the printable electrolytes and the thickness of the photoelectrode are regulated. The results show that the polymers composition has little effect on the conversion efficiency of the QS-DSSCs under ambient-light conditions. However, the iodine concentration and the thickness of the titanium dioxide film are important parameters. The experimental results indicate that the printable electrolyte containing 0.01 M iodine, and a titanium dioxide photoelectrode with the thickness of 4 µm main layer and 4 µm scattering layer are the optimal condition to obtain high cell efficiencies. It also shows that the best QS-DSSCs have high recombination resistance and high incident photon to current efficiency values, which contribute, respectively, to the high open circuit voltage and the current density of the corresponding cells. Therefore, the cells can achieve efficiencies of 15.39% and 20.63% under 200 and 600 lx illuminance, respectively. These efficiencies are almost similar to the conversion efficiencies of the corresponding liquid-state DSSC. By applying this printable electrolyte to a sub-module cell, an energy conversion efficiency of 12.23% is achieved under 200 lx illuminance. The study of long-term stability shows that the efficiency of the QS-DSSC can retain 97% of its initial performance after 1000 h testing under 200 lx illuminance, exhibiting high stability of the cells.

Highly efficient quasi-solid-state dye-sensitized solar cells (QS-DSSCs) are fabricated using nanocomposite gel electrolytes and applied under room light conditions (200 lx). To obtain high energy conversion efficiency in QS-DSSCs, the important components of the DSSC are systematically optimized based on their performance in liquid-state DSSCs. It shows that the liquid cell using the 3-methoxypropionitrile-based cobalt electrolyte has higher efficiency (18.91%) than the cell using the acetonitrile-based electrolyte (17.82%) under 200 lx illumination due to the higher charge recombination resistance at the photoelectrode/electrolyte interface for the 3-methoxypropionitrile system. Poly(vinylidene fluoride-co-hexafluoropropylene) is utilized as the gelator of the liquid electrolytes to prepare polymer gel electrolytes. Furthermore, to improve the performance of the QS-DSSCs, different metal oxide nanoparticles are introduced as nanofillers of the polymer gel electrolytes. It shows that the zinc oxide nanof...

Elizabethkingia species are ubiquitous bacteria but uncommonly cause human infection. An outbreak of Elizabethkingia anophelis bacteraemia was observed in a respiratory care center of a tertiary hospital in Taiwan from 2015 to 2018.Clinical and environmental isolates were collected for the outbreak investigation. Pulsed-field gel electrophoresis (PFGE) and complete-genome sequencing were conducted to elucidate the mechanism of transmission.The three-year outbreak involved 26 patients with E. anophelis bacteraemia and the incidence significantly increased during the outbreak period compared with that observed from 2010 to 2014 (P0.05). All 26 clinical isolates during the outbreak period belonged to a cluster by PFGE analysis. In contrast, the PFGE pattern was heterogeneous among comparative historical strains. Hospital tap water was highly contaminated by Elizabethkingia species (18/34, 52.9%); among that, five E. anophelis belonged to the outbreak cluster (5/18, 27.8%). As for the inanimate surface survey, 3.4% sites (4/117) revealed positive growth of E. anophelis including two from feeding tubes/bags and two from sputum suction regulators. All four isolates belonged to the outbreak clone. The outbreak strain had no apparent relationship to currently known E. anophelis strains worldwide through complete-genome sequencing analysis. Specific infection control strategies aimed at water source control and environmental disinfection were implemented subsequently and the outbreak ended in mid-2018.A specific E. anophelis strain was identified from a three-year outbreak. The elucidation of the mechanism of dominance and intra-hospital transmission is crucial for development of corresponsive infection control policies and outbreak control.

Solid-oxide electrolytes (SEs) are an alternative to using conventional organic liquid electrolytes for lithium ion batteries (LIBs) and offer solutions to the challenges associated with safety and energy density. However, SE-based LIBs suffer from high interfacial resistance between the electrolyte and electrodes. In this study, we develop a gelled poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) framework to facilitate Li+ transfer across the interface between an SE pellet of garnet-type Li6.75La3Zr1.75Ta0.25O12 (LLZTO) and a LiFePO4 cathode. The gelled polymeric framework exhibits high ionic conductivity and a large Li+ transference number (tLi+) of 0.67 that results from the synergy between the nitrile and acrylate functionalities and minimizes the formation of ion–solvent clusters and mobility of PF6− anions. The large tLi+ characteristic is advantageous for forming a junction with SEs featuring a unity tLi+ and suppressing polarization caused by PF6− accumulation. When coupled with the LLZTO pellet, the gel polymer electrolyte may exhibit collimated Li+ transport that suppresses Li-dendrite formation. The resulting Li|LLZTO|LiFePO4 battery demonstrates outstanding capacity (e.g., 154 mA h g−1 at 0.1 mA cm−2 and 25 °C), high rate retention, and excellent cycling stability. The present study demonstrates that the gelled P(AN-co-MA) framework acts an ideal interface between the SE and cathode for fabricating quasi-solid LIBs.

The behavior of ethanol oxidation reaction on composite electrodes prepared by deposition platinum on a gold surface (Pt/Au) were studied by cyclic voltammetry and surface enhanced infrared absorption spectroscopy (SEIRAS) analysis. The results show that the Pt electrode has high oxidation activity and significant poison behavior; on the contrary, the Au electrode demonstrates low activity without a poison peak. The SEIRAS analyses reveal that both carbon monoxide (CO) and carbon dioxide (CO

Major challenges in the development of lithium metal batteries (LMBs) are nonuniform Li deposition and substantial variation in Li volume, resulting in Li dendrite growth and Li consumption. A networked solid-state polymer electrolyte (NSPE) that comprises poly(ethylene oxide-co-propylene oxide) (P(EO-co-PO)) and poly(dimethylsiloxane) diglycidyl ether (PDMSDGE) chains and a lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) salt is developed for resolving the Li deposition challenges. The methyl pendants on P(EO-co-PO) and PDMSDGE chains render the NSPE a low-surface-energy film for complete coverages on the high-energy Li electrode and regulating Li+ transport. The low-surface-energy characteristics induces overspreading of the highly lithiophilic C-F ends of the TFSI− anion at the Li electrode–NSPE interface, forming Li−F bonds and facilitating uniform Li deposition. The elastic PDMS chains enable the NSPE to accommodate Li volume changes. Liquid-phase Li||LiFePO4 and Cu||LiFePO4 cells with the NSPE as an artificial interface or a solid-state Li||LiFePO4 cell with the NSPE as solid electrolyte had uniform anodic Li deposition, resulting in long cycle life and high coulombic efficiency. Our study demonstrated that (a) low surface energy to completely cover the Li anode and (b) the presence of interfacial Li − F bonds are two essential requirements for uniform Li deposition in LMBs.

Power generation in indoor environments is the next step in dye-sensitized solar cell (DSSC) evolution. To achieve this goal, a critical recombination route which is usually inhibited by the TiCl4-...

A graphene oxide sponge (GOS) is prepared and utilized as a nanofiller (NF) of an iodide liquid electrolyte for dye-sensitized solar cell (DSSC) application. The concentration effects of the GOS NFs on the conductivity of the electrolyte, and the performance of the DSSCs are studied. The results indicate that the inclusion of GOS NFs markedly enhances the conductivity of the liquid electrolyte. The electrochemical impendence spectroscopy (EIS) analysis shows that the presence of GOS NFs may increase the recombination resistance (Rct) at the photoelectrode/electrolyte interface and, furthermore, decreases the charge transfer resistance at the Pt counter electrode/electrolyte interface (Rpt). Therefore, the current density (Jsc), open circuit potential (Voc), and fill factor (FF) of the DSSCs can be improved by controlling the concentration of GOS NFs. In this study, the DSSC with 0.50 wt% GOS NFs can achieve the highest energy conversion efficiency of 9.44%, which is higher than that obtained for the corresponding cell without GOS NFs (8.84%).

A graphene oxide sponge (GOS) is utilized for the first time as a nanofiller (NF) in printable electrolytes (PEs) based on poly(ethylene oxide) and poly(vinylidene fluoride) for quasi-solid-state dye-sensitized solar cells (QS-DSSCs). The effects of the various concentrations of GOS NFs on the ion diffusivity and conductivity of electrolytes and the performance of the QS-DSSCs are studied. The results show that the presence of GOS NFs significantly increases the diffusivity and conductivity of the PEs. The introduction of 1.5 wt % of GOS NFs decreases the charge-transfer resistance at the Pt-counter electrode/electrolyte interface (Rpt) and increases the recombination resistance at the photoelectrode/electrolyte interface (Rct). QS-DSSC utilizing 1.5 wt % GOS NFs can achieve an energy conversion efficiency (8.78%) higher than that found for their liquid counterpart and other reported polymer gel electrolytes/GO NFs based DSSCs. The high energy conversion efficiency is a consequence of the increase in both...

All-solid-state polymer electrolytes (SPEs) are key for improving lithium-ion battery (LIB) safety and the practical application of metallic Li anodes. The major challenges of developing SPEs are their ionic conductivity, interfacial affinity, and flammability. In this article, synthesis of an SPE comprising lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and poly(ethylene oxide) networked with an acylamino-functionalized crosslinker is reported. The acylamino sites, urethane and biuret linkages, dissociate LiTFSI and may form deep-eutectic-solvent domains to facilitate ion transport. This SPE is fire-retarding because CO2 evolves when the urethane decomposes at high temperatures. When operated at room temperature, the all-solid-state Li|SPE|LiFePO4 cell exhibits a high rate capability and long lifespan. Due to the high elasticity of the SPE, the polymers can self-rearrange during operation to reduce the Li–SPE interfacial resistance and regulate Li+-ion transport for uniform Li deposition. The rearrangement may involve migration of the low-energy alkane chains in the crosslinker toward the Li-anode, resulting in overspreading of lithiophilic carbonyl groups and F-atoms of TFSI− at the interface. This rearrangement property enables the SPE to act as an artificial interlayer in liquid-electrolyte LIBs. The advantages of using an acylamino-functionalized crosslinker to synthesize a networked SPE for high ionic conductivity and interfacial compatibility are demonstrated.