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Results for “covalent quinazoline networks”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Surpassing the Organic Cathode Performance for Lithium-Ion Batteries with Robust Fluorinated Covalent Quinazoline Networks

Organic electrode materials have promising application prospects in energy storage, but issues including rapid capacity fading and poor power capacity restrict their practical applications. In this study, nanoporous fluorinated covalent quinazoline networks (F-CQNs) were constructed by condensation of fluorinated aromatic aminonitrile precursors via an ionothermal pathway. Precise control of the reaction parameters afforded F-CQN-1-600 material featuring high surface area, permanent porosity, high nitrogen content (23.49 wt %), extended π-conjugated architecture, layered structure, and bipolar combination of benzene and tricycloquinazoline. Synergy among these unique properties leads to a good performance as a cathode source for lithium-ion batteries (LIBs) in terms of high capacity (250 mA h g –1 at 0.1 A g –1 ), high rate capability (105 mA h g –1 at 5.0 A g –1 ), and impressive cycling stability (95.8% retention rate after 2000 cycles at 2.0 A g –1 together with a high Coulombic efficiency of 99.95%), surpassing most of the previous organic cathode counterparts.

25 ENERGY STORAGE↗
DOE OSTI2021

Graphitic Aza-Fused π-Conjugated Networks: Construction, Engineering, and Task-Specific Applications

2D π-conjugated networks linked by aza-fused units represent a pivotal category of graphitic materials with stacked nanosheet architectures. Extensive efforts have been directed at their fabrication and application since the discovery of covalent triazine frameworks (CTFs). Besides the triazine cores, tricycloquinazoline and hexaazatriphenylene linkages are further introduced to tailor the structures and properties. Diverse related materials have been developed rapidly, and a thorough outlook is necessitated to unveil the structure–property–application relationships across multiple subcategories, which is pivotal to guide the design and fabrication toward enhanced task-specific performance. Herein, the structure types and development of related materials including CTFs, covalent quinazoline networks, and hexaazatriphenylene networks, are introduced. Advanced synthetic strategies coupled with characterization techniques provide powerful tools to engineer the properties and tune the associated behaviors in corresponding applications. Case studies in the areas of gas adsorption, membrane-based separation, thermo-/electro-/photocatalysis, and energy storage are then addressed, focusing on the correlation between structure/property engineering and optimization of the corresponding performance, particularly the preferred features and strategies in each specific field. In the last section, the underlying challenges and opportunities in construction and application of this emerging and promising material category are discussed.

36 MATERIALS SCIENCE↗