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In this work, we prepared different initiator solutions containing ether and AlCl 3 by changing the addition sequence of ingredients, studied the interactions between ether and AlCl 3 from the evolution of the Fourier transform infrared (FTIR) spectra by comparison, and investigated the catalytic performances of AlCl 3 affected by ether for isobutylene polymerization. We observed that different preparation methods of initiator solutions could lead to two kinds of interactions between ether and H 2 O/AlCl 3 in hexane. The strong interaction could stabilize carbenium ions and seriously decrease the catalytic performance, whereas the weak interaction could promote isomerization and proton elimination. Moreover, we found that the preparation method of initiator solutions was not a critical factor in CH 2 Cl 2 . Finally, a universal mechanism based on the AlCl 3 -involved interactions in different solvents was proposed to understand the effects of ether on the cationic polymerization catalyzed by AlCl 3 thoroughly.

In this work, toward uniform in situ carbon coating on nano-LiFePO 4 (nano-LFP) via a solid-state reaction, we systematically investigated the effects of the heating rate on the characteristics of the product and process with nano-FePO 4 as the template and iron source. It was found that the high reactivity of nano-FePO 4 almost eliminated the effect of the heating rate on the phase transformation of LiFePO 4 (LFP) but aggravated the impacts on the morphology and the distribution of the carbon layer of the final product. The uniform carbon coating on nano-LFP was found to correspond to a moderate diffusion rate of gas molecules containing carbon, as determined by the thermal decomposition characteristics of the carbon source and the heating rate together. This strategy showed promise in the accelerated synthesis of nano-LFP/carbon composites with high electrochemical performance and was verified to be effective when using different carbon sources, sucrose and polyvinyl alcohol, which had distinct differences in thermal decomposition characteristics. As a result, we achieved the preparation of nano-LFP with an excellent rate performance (140 mA•h•g −1 @10 C) using a high heating rate (15 °C/min), low calcination temperature (650 °C), and short calcination time (4 h).

Better mixing could produce more active centers to accelerate the polymerization by promoting the consumption of carbonium ions.

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A facile strategy to construct composites of amorphous FePO 4 (a-FePO 4 ) nanoparticles and carbon additives with high dispersion and tap density was developed in this work, in which the a-FePO 4 •2H 2 O nanoparticles were handled without drying until being mixed with carbon nanomaterials in water to assure high dispersion of a-FePO 4 • 2H 2 O nanoparticles and carbon nanomaterials; the controlled sedimentation was exploited by rapid adjustment of the pH value via a micromixer to obtain the composites that are easy to manipulate; the composites were endowed with high tap density after simple ball-milling. Using this strategy, hybrid carbon additives were uniformly introduced into the a-FePO 4 cathode to form a hierarchical 3D conductive network. Through proper distribution of these components to provide both long-and short-range electron pathways, the reversible discharge capacity could reach 175.6 mA h g −1 at 0.1 C and 139.1 mA h g −1 at 5 C. The composites of a-FePO 4 , carbon black, and carbon nanotubes (CNT) exhibited the distinct advantages of low cost and excellent rate capacity over the composites of a-FePO 4 and CNT, indicating the importance of optimizing the hierarchical structure of cathode composites. The high effectiveness of this construction strategy to build a hierarchical conductive network is also promisingly used for the development of other functional nanocomposites.

In this work, we focused on the interpretation on a nonclassical crystallization route of Na x Mn­[Fe­(CN)6] y ·nH2O (0 < x < 2, 0 < y < 1, MnHCF) nanocrystal preparation via a bottom-up approach. Combining explosive homogeneous nucleation in the microreactor and subsequent crystal growth in the microtube, we carefully studied the dynamic behaviors of MnHCF crystallization under a high time resolution and found that in the early growth stage, it went through a rapid transition of morphology and crystal structure with the enrichment of the sodium content and the decrease of Fe­(CN)6 defect and lattice water. Meanwhile, reducing the primary particle size, increasing the particle concentration, or adjusting the sodium ion concentration could accelerate the transition process, and the sodium ion also played an important role in the anisotropic aggregation-mediated growth. Based on these cognitions, we proposed the growth mechanism of the nonclassical crystallization process from the interplay of free-energy landscapes and particle reaction dynamics. In addition, the crystal architecture laws of MnHCF via a bottom-up approach were summarized to afford rapid and flexible regulation on morphologies and crystal composites.

In this work, for the performance enhancement of iron hexacyanoferrate, an electrochemically active Mn-doped iron hexacyanoferrate cathode is fabricated via a bottom-up approach. It is found that the pre-treatment of interstitial water and appropriate Mn doping are two keys to achieving higher capacity and higher stability. The interstitial water has a trade-off effect between the alleviation of volume expansion upon Na+ (de)­intercalation and the retardation of Na-ion diffusion. The moisture-tailored iron hexacyanoferrate with appropriate Mn doping exhibits a high initial Coulombic efficiency of 94.8%, enhanced capacity and rate performance, and excellent cycling stability. These results benefit from the fact that the extraction/insertion of Na ions from/into the lattice via a solid-solution mechanism correspond to both the slight volume expansion and fast sodium diffusion rate; otherwise, the removal of interstitial water and a higher Mn content might lead to poor cycling stability due to excessive volume expansion resulting from rhombohedral to cubic phase transformation. Finally, the less demand on the control of air humidity for the fabrication of electrodes and the potential for the full cell coupled with hard carbon are also demonstrated, which shows great potential for practical applications.