214-83-5Relevant articles and documents
Dynamic Covalent Synthesis of Crystalline Porous Graphitic Frameworks
Cai, Songliang,Chan, Emory M.,Chen, Hao,Ciston, Jim,Dun, Chaochao,Gordon, Madeleine P.,Li, Xinle,Liu, Yawei,Liu, Yi,Mao, Haiyan,Reimer, Jeffrey A.,Sun, Bing,Tan, Tianwei,Urban, Jeffrey J.,Wang, Hongxia,Zhang, Jian,Zhang, Qiubo,Zheng, Haimei,Zheng, Qi
, p. 933 - 944 (2020)
Porous graphitic framework (PGF) is a two-dimensional (2D) material that has emerging energy applications. An archetype contains stacked 2D layers, the structure of which features a fully annulated aromatic skeleton with embedded heteroatoms and periodic pores. Due to the lack of a rational approach in establishing in-plane order under mild synthetic conditions, the structural integrity of PGF has remained elusive and ultimately limited its material performance. Here, we report the discovery of the unusual dynamic character of the C=N bonds in the aromatic pyrazine ring system under basic aqueous conditions, which enables the successful synthesis of a crystalline porous nitrogenous graphitic framework with remarkable in-plane order, as evidenced by powder X-ray diffraction studies and direct visualization using high-resolution transmission electron microscopy. The crystalline framework displays superior performance as a cathode material for lithium-ion batteries, outperforming the amorphous counterparts in terms of capacity and cycle stability. Insertion of well-defined, evenly spaced nanoscale pores into the two-dimensional (2D) layers of graphene invokes exciting properties due to the modulation of its electronic band gaps and surface functionalities. A bottom-up synthesis approach to such porous graphitic frameworks (PGFs) is appealing but also remains a great challenge. The current methods of building covalent organic frameworks rely on a small collection of thermodynamically reversible reactions. Such reactions are, however, inadequate in generating a fully annulated aromatic skeleton in PGFs. With the discovery of dynamic pyrazine formation, we succeeded in applying this linking chemistry to obtain a crystalline PGF material, which has displayed high electrical conductivity and remarkable performance as a cathode material for lithium-ion batteries. We envision that the demonstrated success will open the door to a wide array of fully annulated 2D porous frameworks, which hold immense potential for clean energy applications. We report the unusual dynamic characteristics of the C=N bonds in the pyrazine ring promoted under basic aqueous conditions, which enables the successful synthesis of two-dimensional porous graphitic frameworks (PGFs) featuring fully annulated aromatic skeletons and periodic pores. The PGF displayed high electrical conductivity and remarkable performance as a cathode material for lithium-ion batteries, far outperforming the amorphous counterparts in terms of capacity and cycle stability.
Electrical and magnetic properties of a radical-based Co(II) coordination complex with C–H?π and π?π supramolecular interactions
Wu, Wen-Hao,Huang, Meng-Jiao,Zeng, Qi,Xian, Wan-Ru,Liao, Wei-Ming,He, Jun
, p. 149 - 153 (2019)
HAN–[rad] radical based supramolecular Co(II) complex, Co-HAN, has been synthesized with reaction of large π-conjugated hexaazatrinaphthylene (HAN), cobalt salt and ethylenediamine reductant through one-pot solvothermal method. In aggregating crystal network of Co-HAN, two kinds of Zig-Zag supramolecular channels are formed by π?π stacking and C–H?π hydrogen-bond interactions, respectively. The supramolecular interactions, especially π?π stacking, help promote the charge transport, leading to an enhanced electrical conductivity (σ = 0.599 × 10?7 S·cm?1). In addition, electron paramagnetic resonance (EPR) measurements indicated of antiferromagnetic interactions between monoradical ligand and Co(II) ion. The temperature-dependent magnetic susceptibility and χmT value suggests that Co-HAN exhibits a normal paramagnetic behavior for an effective spin of 1/2 coming from the unquenched orbit magnetic moment of Co(II) ions.
An all-organic symmetric battery based on a triquinoxalinylene derivative with different redox voltage active sites and a large conjugation system
Huang, Weiwei,Kong, Xiangyue,Lin, Yilin,Sun, Zhaopeng,Zhang, Yi
, p. 26208 - 26215 (2021/12/10)
Organic materials are considered to have broad application prospects in energy storage systems due to their strong designability and abundant resources. Here, we report a triquinoxalinylene derivative tribenzoquinoxaline-5,10-dione (3BQ) containing high redox potential functional groups (CO and CN) and a large number of low redox potential functional groups (unsaturated carbon). This paper uses 3BQ as the cathode and anode to assemble all-organic symmetric batteries. Since 3BQ has denser active sites and a larger conjuated system than triquinoxalinylene (3Q), the 3BQ cathode has an initial capacity of 506 mA h g-1 (Ctheo = 515 mA h g-1) at 0.2C, and the capacity of 3BQ and 3Q cathodes is 210 and 107 mA h g-1 after 300 cycles at 1C. The large conjugated system and planar structure of 3BQ inhibit its dissolution in electrolytes and accelerate the charge transfer rate, resulting in good cycle stability and rate performance for batteries. The all-organic symmetric batteries assembled with pre-lithiated 3BQ and pristine 3BQ deliver an initial capacity of 483 mA h g-1 at 0.2C, a capacity of 172 mA h g-1 after 300 cycles and an energy density of 301 W h kg-1. This work provides a strategy for the development of high-performance LIBs using organic materials as the cathode and anode. This journal is
