Polysulfide shuttling and uncontrollable lithium dendrite growth have hampered the application of lithium–sulfur (Li–S) batteries. Although various materials have been utilized to overcome these obstacles, simple and scalable methods are still needed for Li–S battery commercialization. It is shown for the first time that the layer‐by‐layer (LbL) self‐assembly of 2D nanomaterials can be used to controllably fabricate multifunctional separators that simultaneously trap polysulfides and suppress lithium dendrite growth. The double‐sided “nanobrick wall” structure, constructed by MoS2/poly(diallyl dimethyl ammonium chloride) hybrid in conjunction with poly(acrylic acid) (PAA), provides a physical shield against polysulfides and the chemical adsorption of such species by MoS2 and PAA. At the same time, the robust and Li‐ion conducting MoS2 layers strengthen the separator and regulate Li deposition, thereby effectively suppressing Li dendrite formation. As a result, a simple sulfur cathode battery with an ultralight separator coating (0.10 mg cm−2) is able to achieve an outstanding cycle stability with a capacity decay as low as 0.029% per cycle over 2000 cycles and a reversible areal capacity ≈2.0 mAh cm−2 at 1 C. The proposed LbL approach opens the door to the simple, scalable, and economic fabrication of advanced functional separators for use in the real world.
A simple, yet robust route to prepare polymer nanoparticles with tunable internal structures through supramolecular assembly within emulsion droplets is presented. Nanoparticles with various internal morphologies, including dispersed spheres, dispersed spirals, stacked toroids, and concentric lamellae, are obtained due to the 3D confinement and variation of hydrogen-bonding agent. This method also allows us to form mesoporous particles through further disassembly of the supramoleclar assemblies by rupturing the hydrogen bonding.
Controlling the kinetics and gelation of photopolymerization is a significant challenge in the fabrication of complex three-dimensional (3D) objects as is critical in numerous imaging, lithography, and additive manufacturing techniques. We propose a novel, visible light sensitive "photoinitibitor" which simultaneously generates two distinct radicals, each with their own unique purpose-one radical each for initiation and inhibition. The Janus-faced functions of this photoinitibitor delay gelation and dramatically amplify the gelation time difference between the constructive and destructive interference regions of the exposed holographic pattern. This approach enhances the photopolymerization induced phase separation of liquid crystal/acrylate resins and the formation of fine holographic polymer dispersed liquid crystal (HPDLC) gratings. Moreover, we construct colored 3D holographic images that are visually recognizable to the naked eye under white light.
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