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Because of its high energy density and low cost, the room-temperature sodium-sulfur (RT Na-S) battery is a promising candidate to power the next-generation large-scale energy storage system. However, its practical utilization is hampered by the short life span owing to the severe shuttle effect, which originates from the "solid-liquid-solid" reaction mechanism of the sulfur cathode. In this work, fluoroethylene carbonate is proposed as an additive, and tetraethylene glycol dimethyl ether is used as the base solvent. For the sulfurized polyacrylonitrile cathode, a robust F-containing cathode-electrolyte interphase (CEI) forms on the cathode surface during the initial discharging. The CEI prohibits the dissolution and diffusion of the soluble intermediate products, realizing a "solid-solid" reaction process. The RT Na-S cell exhibits a stable cycling performance: a capacity of 587 mA h g

Fiber-based linear actuators (FLAs) are a key module in microrobots and biomimetic devices. It has been a great challenge to develop linear actuators that can balance output stress and output strain and hence provide high working density. Herein, we report the preparation and performance of a FLA system made from commercially available materials and allowed mass production at relatively low cost. The FLAs can lift up or lay down objects more than 1000 times of its own weight during active contraction and expansion under environmental stimuli. The contraction ratio and output stress can reach 30% and 0.24 MPa, respectively, and the sustainable work density is about 80 J/kg, which is 10 times the typical value of human skeletal muscles. Especially, the FLAs show stable catch-state (lock-up state) with no creeping and no further energy consumption.

In this work, a polyelectrolyte complex (PEC) fiber of alginate (ALG) and poly(diallyldimethylammonium chloride) (PDDA) is prepared by restricting polyelectrolyte complexation with salt to fit wet-...

Poly(acrylic acid) (PAA) was partially grafted with dopamine (PAA-dopa), and then layer-by-layer assembled with poly(vinylpyrrolidone) (PVPON) to prepare hydrogen-bonded (PVPON/PAA-dopa)n film. Polydopamine (PDA) was deposited on (PVPON/PAA-dopa)n film in the presence of oxidant, and hence the whole (PVPON/PAA-dopa)nPDA film was cross-linked. (PVPON/PAA-dopa)nPDA could be utilized as a platform to produce the free-standing Janus film because of the easy detaching process and various chemical reactivity of PDA layer. Ag nanoparticles were formed on (PVPON/PAA-dopa)nPDA film by electroless metallization. 1H,1H,2H,2H-Perfluorodecanethiol (PFDT) was used to further modify the film through Michael addition. After detaching from the substrate, (PVPON/PAA-dopa)20PDA/Ag/PFDT exhibits reversible swelling–shrinking behavior as the pH value changes. This free-standing film shows Janus character, one side is hydrophobic, whereas the other side is hydrophilic. In addition, the hydrophobic surface exhibits a surface-en...

A thiol-substituted carotenoid, 7‘-apo-7‘-(4-mercaptomethylphenyl)-β-carotene, (AMC) was allowed to self-assemble on polycrystalline gold surfaces. The stability, packing density, optical absorption, and hydrophobicity of the resulting monolayers were investigated with X-ray photoelectron spectroscopy (XPS), Fourier transform infrared reflection−absorption spectroscopy (FTIR-RAS), UV-Vis spectroscopy, spectroscopic ellipsometry, and contact angle measurements. XPS and spectroscopic ellipsometry measurements reveal the saturation coverage is ∼4 × 1014 AMC molecules/cm2 and the film thickness is ∼20 A, respectively. FTIR-RAS and contact angle measurements suggest that the polyene chains are packed well enough to create a hydrophobic interface.

2-Diformylmethylene-1,3-diselenole was prepared and condensed with dithiolium phoshonium bromides and dithiolium phosphonates in the presence of base to give dendralene-type vinylogs of TTF bearing a 1,3-diselenole moiety. The electrochemistry of these dendrimers was studied. SEEPR measurements were also carried out. Calculations were carried out on the radical cations and correlated with the EPR values.

Self-assembled monolayers (SAMs) formed by adsorption of thiols onto gold provide a flexible method to study the electrochemical reactivity of 7,7‘-diapo-(7E,7‘Z)-diphenylcarotene (DDC) on such bar...