Solid-state polymer electrolytes are considered to be the most promising electrolytes for next-generation high-energy rechargeable lithium batteries due to the advantages of high safety, good mechanical flexibility, and easy film-formation ability. Among all the polymers, polyethylene oxide (PEO) is demonstrated to be a feasible polymer host, based on its high dielectric constant and strong lithium salt dissolving ability. However, the practical application of PEO in the all-solid-state lithium batteries is limited mainly by its low ionic conductivity at room temperature. For decades, researchers dedicate to increase the ion conductivity at room temperature and mechanical properties according to the technology strategy of composite polymer electrolytes. In particular, the electrode/electrolyte interface structure is designed and optimized according to the requirement of different battery systems. Accordingly, in this review, the basic characteristics, ion transport mechanism, composite mechanism of inert/active fillers with polymers, and electrode/ electrolyte interface structures are evaluated for the PEO-based composite polymer electrolytes. Finally, the outlook is presented for future development of the solid-state polymer electrolytes and high-energy rechargeable lithium batteries.
Dissolution of metal oxides is fundamentally important for understanding mineral evolution and micromachining oxide functional materials. In general, dissolution of metal oxides is a slow and inefficient chemical reaction. Here, by introducing oxygen deficiencies to modify the surface chemistry of oxides, we can boost the dissolution kinetics of metal oxides in water, as in situ demonstrated in a liquid environmental transmission electron microscope (LETEM). The dissolution rate constant significantly increases by 16-19 orders of magnitude, equivalent to a reduction of 0.97-1.11 eV in activation energy, as compared with the normal dissolution in acid. It is evidenced from the high-resolution TEM imaging, electron energy loss spectra, and first-principle calculations where the dissolution route of metal oxides is dynamically changed by local interoperability between altered water chemistry and surface oxygen deficiencies via electron radiolysis. This discovery inspires the development of a highly efficient electron lithography method for metal oxide films in ecofriendly water, which offers an advanced technique for nanodevice fabrication.
Decoding the principles of cluster-based framework assembly at the molecular level remains a persistent challenge. Herein, we isolated and characterized a novel water-stable three-dimensional (3D) metal-organic open framework [Cl@Ag(cPrC≡C)Cl·(p-TOS)·1/3HO] (SD/Ag14, cPrC≡CH = cyclopropylacetylene; p-TOS = p-toluenesulfonate), which contains a chloride-templated Ag cluster as building block. For SD/Ag14, one chloride acts as the template to shape the Ag cluster and the other bridges the clusters to a 3D pcu-h open framework. As revealed by high resolution electrospray mass spectrometry (HRESI-MS), the Ag-Ag species are potential cluster-based intermediates to the 3D pcu-h framework, which authenticates a preconceived idea that the 3D framework is hierarchically assembled from the silver clusters as observed in solid state. Interestingly, SD/Ag14 can be used effectively to remove the environmental pollutant CrO from wastewater through anion exchange in a single-crystal-to-single-crystal (SC-SC) transformation fashion. Furthermore, SD/Ag14 exhibits excellent antibacterial activity against Staphylococcus aureus, thus making it a potential antibacterial agent.
Controlling phase transition in functional materials at nanoscale is not only of broad scientific interest but also important for practical applications in the fields of renewable energy, information storage, transducer, sensor, and so forth. As a model functional material, vanadium dioxide (VO) has its metal-insulator transition (MIT) usually at a sharp temperature around 68 °C. Here, we report a focused electron beam can directly lower down the transition temperature of a nanoarea to room temperature without prepatterning the VO. This novel process is called radiolysis-assisted MIT (R-MIT). The electron beam irradiation fabricates a unique gradual MIT zone to several times of the beam size in which the temperature-dependent phase transition is achieved in an extended temperature range. The gradual transformation zone offers to precisely control the ratio of metal/insulator phases. This direct electron writing technique can open up an opportunity to precisely engineer nanodomains of diversified electronic properties in functional material-based devices.
An aligned nanofiber matrix is obtained from the self-assembly of an oligopeptide amphiphile, which can capture the residual dipolar couplings of biomolecules.
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