A variety of nanoporous transition metals, Fe, Co, Au, Cu, and others, have been readily formed by a scalable, room-temperature synthesis process. Metal halide compounds are reacted with organolithium reductants in a nonpolar solvent to form metal/lithium halide nanocomposites. The lithium halide is then dissolved out of the nanocomposite with a common organic solvent, leaving behind a continuous, three-dimensional network of metal filaments that form a nanoporous structure. This approach is applicable to both noble metals (Cu, Au, Ag) and less-noble transition metals (Co, Fe, Ni). The microstructures of these nanoporous transition metals are tunable, as controlling the formation of the metal structure in the nanocomposite dictates the final metal structure. Microscopy studies and nitrogen adsorption analysis show these materials form pores ranging from 2 to 50 nm with specific surface areas from 1.0 m/g to 160 m/g. Our analysis also shows that pore size, pore volume, and filament size of the nanoporous metal networks depend on the mobility of target metal and the amount of lithium halide produced by the conversion reaction. Further, it has been demonstrated that hybrid nanoporous structures of two or more metals could be synthesized by performing the same process on mixtures of precursor compounds. Metals (e.g., Co and Cu) have been found to stabilize each other in nanoporous forms, resulting in smaller pore sizes and higher surface areas than each element in their pure forms. This scalable and versatile synthesis pathway greatly expands our access to additional compositions and microstructures of nanoporous metals.

one being the pure electrolyte and the other being a mixture of cathode active material and the solid electrolyte. Therefore, the electrolyte layers are normally thick (on the order of sub-millimeters), which results in low energy densities for solid state batteries. In addition, when lithium metal or cathode is attached to the electrolyte layer, the electrode/electrolyte interface suffers from voids and poor contacts which produce large resistances. [13,14] These complexities are major hurdles for practical applications of SEs in all-solid-state batteries.To address these challenges, a liquidbased synthesis and processing route to SEs is highly desirable because it can potentially achieve a thin electrolyte layer with good interface contact with electrode. [15][16][17] In the case of sulfide electrolytes, precursor materials (e.g., Li 2 S and P 2 S 5 ) are dispersed in solvents, such as tetrahydrofuran (THF), [18,19] 1,2-dimethoxyethane (DME), [20] acetonitrile, [19] ethyl acetate, [21] and dimethyl carbonate (DMC), [22] and can react with each other to form SEs. However, these reported solution-processing methods have critical limitations. First, SEs solutions are limited to forming coatings on cathode materials and cannot be directly applied to Li metal because the reported processing solvents are highly reactive. [15][16][17]23] Furthermore, the synthesized SEs usually require post processing at elevated temperatures of around 200-240 °C, [19,20,22,24] which is over the Li melting point (180 °C). Second, none of these SEs have been fabricated as a thin film. Instead, they are precipitated as particles which need additional processing steps to be compatible with conventional battery fabrication.In this work, we report a new strategy for synthesizing thin sulfide-based SEs using a solution-processing method. A conductive β-Li 3 PS 4 that remains stable in a soluble form was successfully produced by inducing a chemical reaction between soluble polysulfides and P 2 S 5 in diethylene glycol dimethyl ether (DEGDME) solvent. Due to the use of nonreactive solvent, it is possible to coat this solution directly on Li metal. Hence, the formation of a thin and dense SE layer (thickness of ≈50 µm) with favorable interfacial contact was demonstrated. This solution-processing method does not require high temperature heat treatment or pressing steps. It is the simplest way to produce a thin SE layer directly on Li metal and will provide new insights to fabricating solid-state lithium batteries with high energy densities.Solid state batteries hold the promise of enhanced safety and higher energy density over conventional lithium-ion batteries with flammable organic electrolytes. However, advancement of solid electrolyte materials has yet to translate into practical batteries due to the need to process the powders into thin sheets with high pressure compaction and high temperature sintering. Here, a new strategy is developed for synthesizing sulfide-based solid electrolyte using low-temperature solution processing, which is a ...

Conversion reaction synthesis, namely, reacting an organolithium reducing agent with a metal chloride to produce a metal/LiCl nanocomposite and then removing lithium chloride with a polar organic solvent, is an efficient and scalable way to fabricate a variety of three-dimensional, bicontinuous nanoporous transition metals. Thermal annealing was investigated as a means to tune the morphology of these nanoporous metals. X-ray diffraction studies were used to investigate the effect of thermal annealing on the size and strain of phases in Cu/ LiCl, Co/LiCl, and Fe/LiCl nanocomposites, while electron microscopy and nitrogen adsorption studies were used to study the porosity and surface properties of the resulting nanoporous metals after LiCl was removed from the annealed nanocomposites. Annealing metal/LiCl nanocomposites resulted in the controlled growth of the metal nanoparticles, the rate of which depended on the diffusivity of the metal. It was observed that annealing nanocomposites produced more robust nanoporous metals with increased porosity under certain conditions. Overall, it was found that annealing the as-formed nanocomposites rather than the isolated nanoporous metals provides finer control of the conversion synthesis process and allows for the design of more optimized pore structures and thus enhanced suitability for catalytic and electrochemical applications.

Magnetostrictive composite known as magnetostrictive nanocellulose membrances (MNMs) were fabricated by embedding Terfeonol-D particles into cellulose nanofibers (CNFs). MNMs inherit flexibility and biodegradability from CNF while exhibiting magnetomechanical responses; as such, the valuable rare-earth (Terfenol-D) particles can be recycled. Various orientations of the Terfenol-D particles were induced in the MNMs, and those with in-plane alignment showed the strongest magnetostrictive effect but the lowest Villari effect. Materials with such a unique combination of properties dovetail nicely with Internet of Things that require ubiquitous sensing, actuation, and energy harvesting in one package.