Towards Durable and High-Rate Rechargeable Aluminum Dual-ion Batteries via a Crosslinked Diphenylphenazine-based Conjugated Polymer Cathode

Rechargeable aluminum battery (RAB) is expected to be a promising energy storage technique for grid-scale energy storage. However, the development of RABs is seriously plagued by the lack of suitable cathode materials. Herein, we report two p-type conjugated polymers of L-PBPz and C-PBPz with the same building blocks of diphenylphenazine but different linkage patterns of linear and crosslinked structures as the cathode materials for Al dual-ion batteries. Compared to the linear polymer skeleton in L-PBPz, the crosslinked structure endows C-PBPz with amorphous nature and low dihedral angles of the polymer chains, which severally contribute to the fast diffusion of AlCl4 - with large size and the electron transfer during the redox reaction of diphenylphenazine. As a result, C-PBPz delivers a much better rate performance than L-PBPz. The crosslinked structure also leads to a stable cyclability with over 80000 cycles for C-PBPz. Benefiting from the fast kinetics, meanwhile, the C-PBPz cathode could realize a high redox activity of 117 mAh g-1, corresponding to an areal capacity of 2.30 mAh cm-2, even under a high mass loading of 19.7 mg cm-2 and a low content of 10 wt% conductive agent. These results might boost the development of polymer cathodes for RABs.

Diphenolic acid-modified PAMAM/chlorinated butyl rubber nanocomposites with superior mechanical, damping, and self-healing properties

Based on its excellent damping properties, traditional rubber has been widely used in various industries, including aerospace, rail transit and automotive. However, the disadvantages of effective damping area, unstable damping performance, easy fatigue, and aging, greatly limited the further application of rubber materials. Thus, it is important to develop novel modified rubber damping materials. Herein, polyamidoamine dendrimers with terminal-modified phenolic hydroxyl and amine groups (G2 PAMAM-H) were designed and used as modifiers to improve the damping performance of chlorinated butyl rubber (CIIR). The results showed that the modification of G2 PAMAM by diphenolic acid can avoid its aggregation in the CIIR matrix. CIIR/G2 PAMAM-H nanocomposites exhibited high tan δ _max of 1.52 and wide damping temperature region of 140°C (tan δ > 0.55)at a very low loading (4.32 wt.%), which were strongerthan that of pure CIIR and CIIR/G2 PAMAM nanocomposites. In addition, these nanocomposites also exhibited a unique self-healing ability by multiple hydrogen bonds, which can effectively extend the life of the rubber material in actual production. Therefore, the dendrimer modification provided unique development opportunities for elastomers in certain highly engineered fields, such as vehicles, rail transit, aerospace, etc.

Separation performance of a new triptycene-based stationary phase with polyethylene glycol units and its application to analysis of the essential oil of Osmanthus fragrans Lour

This work presents a new triptycene-based stationary phase (TP-PEG) combining the three-dimensional (3D) triptycene (TP) framework with polyethylene glycol (PEG) moieties for gas chromatographic (GC) separations. Its statically coated capillary column showed high column efficiency of 5263 plates/m determined by naphthalene at 120 °C. Its Rohrschneider-McReynolds constants and Abraham solvation system constants were measured to characterize its polarity and molecular interactions with analytes of different types. As evidenced, the TP-PEG column showed high-resolution performance for the isomers of anilines, phenols, halobenzenes and alkanes with distinct advantages over the PEG columns, particularly those critical isomers such as 3,5-/2,3-xylidine (R = 2.94), m-/p-chlorotoluene (R = 1.92), p-/m-cresol (R = 1.89), 2,2-dimethylbutane/2-methylpentane (R = 1.51), 2,2,3-trimethylbutane /2,3-dimethyl pentane (R = 1.74) and 2,3-dimethylpentane/n-heptane (R = 1.92). In addition, it exhibited good column repeatability and reproducibility with the relative standard deviation (RSD) values of 0.02%-0.09% for run-to-run, 0.13%-0.22% for day-to-day and 2.7%-4.1% for column-to-column, respectively, and a wide operational temperature range (30 °C-280 °C) . Its application to GC-MS analysis of the essential oil of Osmanthus fragrans has proven its good potential for practical analysis of complex samples.

Triptycene-based stationary phases for gas chromatographic separations of positional isomers

This work presents the investigation of two triptycene-based materials (TP-3OB and TP-3Im) as the stationary phases for gas chromatographic (GC) separations. The TP-3OB and TP-3Im capillary columns fabricated by static coating exhibited column efficiency of 3000-3500 plates/m for n-dodecane at 120 °C. Also, their McReynolds constants and Abraham system constants were determined to characterize their polarity and molecular interactions with analytes. On the basis of the unique 3D TP architecture, the TP-3OB and TP-3Im stationary phases exhibited complementary high-resolution performance for analytes of a wide ranging polarity, including alkylbenzenes, alkylnaphthalenes, halobenzenes, phenols and anilines, respectively. Moreover, the TP-based columns exhibited good repeatability and reproducibility on the retention times of analytes with the relative standard deviation (RSD) values in the range of 0.01-0.14% for run-to-run, 0.11-0.47% for day-to-day and 0.68-4.7% for column-to-column, respectively. Additionally, their applications for the determination of isomer impurities in the commercial reagents of o-dichlorobenzene, p-/m-diethylbenzene, o-toluidine and 2,3-/3,5-xylidine proved their good potential for practical analysis. This work demonstrates the promising future of the triptycene-based stationary phases for chromatographic separations.

Facile Synthesis of a Pentiptycene-Based Highly Microporous Organic Polymer for Gas Storage and Water Treatment

Rigid H-shaped pentiptycene units, with an intrinsic hierarchical structure, were employed to fabricate a highly microporous organic polymer sorbent via Friedel-Crafts reaction/polymerization. The obtained microporous polymer exhibits good thermal stability, a high Brunauer-Emmett-Teller surface area of 1604 m² g^-1, outstanding CO₂, H₂, and CH₄ storage capacities, as well as good adsorption selectivities for the separation of CO₂/N₂ and CO₂/CH₄ gas pairs. The CO₂ uptake values reached as high as 5.00 mmol g^-1 (1.0 bar and 273 K), which, along with high adsorption selectivity values (e.g., 47.1 for CO₂/N₂), make the pentiptycene-based microporous organic polymer (PMOP) a promising sorbent material for carbon capture from flue gas and natural gas purification. Moreover, the PMOP material displayed superior absorption capacities for organic solvents and dyes. For example, the maximum adsorption capacities for methylene blue and Congo red were 394 and 932 mg g^-1, respectively, promoting the potential of the PMOP as an excellent sorbent for environmental remediation and water treatment.

From diiodo Tröger's bases towards halogen-bonded porous organic crystalline materials

Diiodo Tröger's base derivatives proved to be self-complementary tectons that are particularly suitable for the formation of porous supramolecular structures by halogen bonding.

Porous Hydrogen-Bonded Organic Frameworks

Ordered porous solid-state architectures constructed via non-covalent supramolecular self-assembly have attracted increasing interest due to their unique advantages and potential applications. Porous metal-coordination organic frameworks (MOFs) are generated by the assembly of metal coordination centers and organic linkers. Compared to MOFs, porous hydrogen-bonded organic frameworks (HOFs) are readily purified and recovered via simple recrystallization. However, due to lacking of sufficiently ability to orientate self-aggregation of building motifs in predictable manners, rational design and preparation of porous HOFs are still challenging. Herein, we summarize recent developments about porous HOFs and attempt to gain deeper insights into the design strategies of basic building motifs.

A triptycene-based porous hydrogen-bonded organic framework for guest incorporation with tailored fitting

By employing a robust and non-coplanar building block strategy, a triptycene-based hydrogen-bonded organic framework was constructed with almost no sacrifice of molecular surfaces, and it was capable of incorporating C60 molecules in high concentration in the channels with tailored fitting.