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We synthesized a surfactant-encapsulated polyoxoanion, (DODA)16As4W30Cu4O112‚114H2O (denoted SEC-1), which possesses a hydrophobic dimethyl dioctadecylammonium (DODA) shell and an encapsulated hydrophilic polyoxoanion core in organic phases. The novel organic/inorganic composite can form stable Langmuir monolayers, but it is significantly distorted when spread onto an air/water interface although the general core-shell structure seems to remain. Langmuir-Blodgett (LB) films of SEC-1 are readily prepared by transferring the monolayers onto substrates with a transfer ratio near 1. It has been proposed that there exist well-orientated alkyl chains and highly defined layer structure in LB films. Fourier transformation infrared spectroscopy at different temperatures indicates that two obvious phase transitions appear near 34 and 47 °C for multilayer LB films of SEC-1. The polyoxoanion can be organized to some extent within LB films with its long axis parallel to the substrate by comparing the IR transmission spectrum with the reflection-absorption spectrum. The one-monolayer LB film of SEC-1 possesses a homogeneous and flat surface morphology, and a water contact angle of 104 ( 3°for odd-layer LB films shows a highly hydrophobic surface.

Lithium metals fit the growing demand of high-energy density rechargeable batteries because of their high specific capacity and low redox potential. However, the lithium-metal anodes are abandoned because of various defects. In this study, we apply composite plating into the protection of lithium-metal anodes. We confirmed that the Mg 3 N 2 nanoparticle dispersed in the ether electrolyte can be easily composite-plated with lithium, resulting in a flat, dense, and dendrite-free lithium deposition layer during the electrodeposition process. In addition, the Mg 3 N 2 plated in the lithium metal phase would react with lithium and then generate a Li 3 N-rich solid electrolyte interphase (SEI) layer, mitigating continuous side reactions of the electrolyte on the Li metal. In addition, another product of the reaction is Mg which can work as lithiophilic sites in electrodeposition. The combined effect of the two fields can effectively improve the performance of lithium metal anodes. The Li 3 N-rich SEI layer would grow well on the surface of the three-dimensional (3D) lithium anode by composite plating. Furthermore, composite plating with the Mg 3 N 2 -containing electrolyte is a viable route that can be used for various 3D current collectors easily with a small volume effect. Here, we show that the composite plating 3D lithium metal anode is successfully applied in the Li−S battery with a long lifetime.

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