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We have designed and tested several synthesis routes targeting a highly fluorinated disordered rocksalt (DRX) cathode, Li1.2Mn0.4Ti0.4O1.6F0.4, with each route rationalized by thermochemical analysis. Precursor combinations were screened to raise the F chemical potential and avoid the formation of LiF, which inhibits fluorination of the targeted DRX phase. MnF2 was used as a reactive source of F, and Li6MnO4, LiMnO2, and Li2Mn0.33Ti0.66O3 were tested as alternative Li sources. Each synthesis procedure was monitored using a multi-modal suite of characterization techniques including X-ray diffraction, nuclear magnetic resonance, thermogravimetric analysis, and differential scanning calorimetry. From the resulting data, we advance the understanding of oxyfluoride synthesis by outlining the key factors limiting F solubility. At low temperatures, MnF2 consistently reacts with the Li source to form LiF as an intermediate phase, thereby trapping F in strong Li-F bonds. LiF can react with Li2TiO3 to form a highly lithiated and fluorinated DRX (Li3TiO3F); however, MnO is not easily incorporated into this DRX phase. Although higher temperatures typically increase solubility, the volatility of LiF above its melting point (848 °C) inhibits fluorination of the DRX phase. Based on these findings, metastable synthesis techniques are suggested for future work on DRX fluorination.

Reactive compatibilization of immiscible polymer blends using a preferred compatibilizer leaves the following question: How much loading of a compatibilizer is good enough and what maximum properties can be achieved? A good understanding of the process can help solve the reutilization of mixed waste plastics. Here, the reactive compatibilization of polypropylene-graftmaleic anhydride (PP-g-MAH) on polypropylene/polyamide 66 (PP/PA66) blends is quantitatively assessed using thermorheological, microoptical, spectroscopic, and x-ray scattering-based characterization tools. The overall compositions of all PP(60%)/PA66(30%)/PP-g-MAH(10%) blends are kept constant while systematically controlling the degree of the chemical reaction by varying the sequential addition of PP-g-MAH to the melt mixture. The first feeding of PP-g-MAH (x%,0[less than or equal to]x[less than or equal to]10) is conducted at 280[degrees]C and the second feeding of (10 - x)% is at 200[degrees]C. During the first step, a larger amount of chemical activity is observed up to 4%-6% addition of PP-g-MAH. The constant chemical composition allows a systematic comparison of the compatibilizer-dependent thermal, rheological, morphological, and mechanical properties. With an increased degree of interfacial reaction, the size of dispersed PA66 domains decreases to register improved interfacial adhesion with the PP matrix, yielding enhanced Young's modulus and absolute failure strength of the isotropic matrix. KEYWORDS polyamide 66, polymer composite, polymer recycling, polypropylene, polypropylene-graft-maleic anhydride, reactive extrusion, 1 | INTRODUCTION Over the past decades, plastic waste has been one of the most serious environmental issues in the world because of its prolonged lifetime. Although a large amount [...]

High boiling-point solvent additives, such as 1,8-diiodooctane, have been widely used to tune nanoscale phase morphology for increased efficiency in bulk heterojunction organic solar cells. However, liquid-state solvent additives remain in the active films for extended times and later migrate or evaporate from the films, leading to unstable device performance. Here, a solid-state photoactive molecular mediator, namely N(BAI)3, is reported that could be employed to replace the commonly used solvent additives to tune the morphology of bulk heterojunction films for improved device performance. The N(BAI)3 mediator not only resides in the active films locally to fine tune the phase morphology, but also contributes to the additional absorption of the active films, leading to ∼11% enhancement of power conversion efficiency of P3HT:PC60BM devices. Comparative studies are carried out to probe the nanoscale morphologies using grazing incidence wide-angle X-ray scattering and complementary neutron reflectometry. The use of 1 wt% N(BAI)3 is found to effectively tune the packing of P3HT, presumably through balanced π-interactions endowed by its large conjugated π surface, and to promote the formation of a PC60BM-rich top interfacial layer. These findings open up a new way to effectively tailor the phase morphology by photoactive molecular mediators in organic photovoltaics.

The use of block copolymers to compatibilize immiscible plastics is an important strategy for upcycling municipal plastic wastes. Multiblock copolymers (MBCPs) have been proven to be more effective compatibilizers than di- and tri-block copolymers. Herein, we probe the interface structure of an effective multiblock copolymer compatibilizer and compare that with an ineffective triblock copolymer (TBCP). The interface activity of the compatibilizers is understood through a combination of small-angle neutron and x-ray scatterings (SANS and SAXS), by using deuterated homopolymer matrix and protonated compatibilizers. SANS analysis suggests that the MBCP forms a thicker interface layer (7-9 nm) than the TBCP (0-4 nm). In addition, SANS data seems to point to a stronger tendency for the MBCP to locate at the interface. Both factors contribute to its effectiveness at compatibilizing immiscible homopolymers. [ABSTRACT FROM AUTHOR]

Solvent‐based CO2 capture consumes significant amounts of energy for solvent regeneration. To improve energy efficiency, this study investigates CO2 fixation in a solid form through solvation, followed by ionic self‐assembly‐aided precipitation. Based on the hypothesis that CO32− ions may bind with monovalent metal ions, we introduced Na+ into an aqueous hexane‐1,6‐diamine solution where CO2 forms carbamate and bicarbonate. Then, Na+ ions in the solvent act as a seed for ionic self‐assembly with diamine carbamate to form an intermediate ionic complex. The recurring chemical reactions lead to the formation of an ionic solid from a mixture of organic carbamate/carbonate and inorganic sodium bicarbonate (NaHCO3), which can be easily removed from the aqueous solvent through sedimentation or centrifugation and heated to release the captured CO2. Mild‐temperature heating of the solids at 80–150 °C causes decomposition of the solid CO2‐diamine‐Na molecular aggregates and discharge of CO2. This sorbent regeneration process requires 6.5–8.6 GJ/t CO2. It was also found that the organic carbamate/carbonate solid, without NaHCO3, contains a significant amount of CO2, up to 6.2 mmol CO2/g‐sorbent, requiring as low as 2.9–5.8 GJ/t CO2. Molecular dynamic simulations support the hypothesis of using Na+ to form relatively less stable, yet sufficiently solid, complexes for the least energy‐intensive recovery of diamine solvents compared to bivalent carbonate–forming ions. [ABSTRACT FROM AUTHOR]