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Garnet-type cubic Li₇La₃Zr₂O₁₂(c-LLZO) is a single-ion conductor, but the electrochemically generated charged vacancies make it a binary ionic electrolyte, which explains the current- and thickness-dependent lithium dendrite initiation dynamics. 

To address the dynamic heterogeneities in porous carbon electrode used in Li-O2 batteries, microscopic charge transfer theory offers much better explanations and predictions for the reactive nucleation and growth dynamics of oxide formation during discharging a Li-O2 battery. 

Abstract Intermittent renewable energy sources can mitigate climate change, but they require high-performance, reliable batteries. The widely used lithium-ion batteries contain Li, Co, and Ni, and the growing demand for these elements, together with their relatively limited sources, has raised concerns about their supply chain stability. Sodium-ion batteries have become an economical alternative. Sodium vanadium phosphate, Na3V2(PO4)3 (NVP), is a compelling candidate with high stability and ionic conductivity due to its polyanionic sodium superionic conductor (NASICON) structure. However, NVP suffers from poor electronic conductivity and requires hierarchical morphology to allow facile ion and electron transfer. Spray-drying has been used to achieve hierarchical secondary particle structures, but the foremost reported NVP syntheses rely on either flammable/toxic organic solvents or expensive nanocarbon additives. In this study, we spray-dry an aqueous suspension without using expensive carbon additives. The obtained NVP sodium-ion half cells showed very high reversible capacity (114.7 mAh g-1 at 0.2C), high rate capability (80.8% capacity retention at 30C), and stable cycling performance (96.7% capacity retention after 1,500 cycles at 10C). This superior performance demonstrates the great promise for NVP batteries as an alternative energy storage option to traditional lithium-ion batteries. 

A comprehensive set of single-component and binary isotherms were collected for ethanol/water adsorption into the siliceous forms of 185 known zeolites using grand-canonical Monte Carlo simulations. Using these data, a systematic analysis of ideal/real adsorbed-solution theory (IAST/RAST) was conducted and activity coefficients were derived for ethanol/water mixtures adsorbed in different zeolites based on RAST. It was found that activity coefficients of ethanol are close to unity while activity coefficients of water are larger in most zeolites, indicating a positive excess free energy of the mixture. This observation can be attributed to water/ethanol interactions being less favorable than water/water interactions in the single-component adsorption of water at comparable loadings. The deviation from ideal behavior can be highly structure-dependent but no clear correlation with pore diameters was identified. Our analysis also demonstrates the following: (1) accurate unary isotherms in the low-loading regime are critical for obtaining physically sensible activity coefficients; (2) the global regression scheme to solve for activity model parameters performs better than fitting activity models to activity coefficients calculated locally at each binary state point; and (3) including the dependence on adsorption potential offers only a minor benefit for describing binary adsorption at the lowest fugacities. Finally, the Margules activity model was found incapable of capturing the non-ideal adsorption behavior over the entire range of fugacities and compositions in all zeolites, but for conditions typical of solution-phase adsorption, RAST predictions using zeolite-specific or even bulk Margules parameters provide an improved description compared to IAST. 

A shift of the Li⁺ion hopping mechanism with temperature in solid-state lithium lanthanum titanate (LLTO) electrolytes was discovered usingab initiometadynamics simulations. 

We report the use of fluorinated polymer zwitterions to build hybrid systems for efficient CO₂electroreduction. 

Zinc metal anodes are attracting much attention to enable more economical and sustainable energy storage devices. However, like other metal anodes, dendritic growths and penetrations of porous separators are still challenging to eliminate. Introducing negative surface charges on the pore walls of separators have been exploited to enforce a uniform incoming Zn-ion flux toward more uniform electrodeposition, but penetrations induced by localized high current densities still remain in available systems. In this work, we report, for the first time, a bipolar separator that exploits the distinct electroosmotic effects of the negative and the positive surface charges. The surface charge effects on Zn dendrite growths were first verified in transparent capillary cells viaoperandovideo microscopy. By stacking the positively charged separator over the negatively charged separator as our proof-of-concept, the system offers preemptively a uniform Zn-ion flux through the negative layer yet starve-stops local metal growths that already penetrated the negative layer autonomously. Chronopotentiometry experiments with the symmetric cells reveal extended short-circuit time compared to control cells. Galvanostatic cycle-life experiments of full cells with the bipolar separator showed excellent cycle life of 5,000 cycles at the rate of 10 C, without signs of metal penetration.