scholarly journals Hydroquinone–pyrrole dyads with varied linkers

2016 ◽  
Vol 12 ◽  
pp. 89-96 ◽  
Author(s):  
Hao Huang ◽  
Christoffer Karlsson ◽  
Maria Strømme ◽  
Martin Sjödin ◽  
Adolf Gogoll

A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C) has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

2019 ◽  
Author(s):  
Edon Vitaku ◽  
Cara Gannett ◽  
Keith Carpenter ◽  
Luxi Shen ◽  
Hector Abruna ◽  
...  

Redox-active covalent organic frameworks (COFs) are promising materials for energy storage devices because of their high density of redox sites, permanent and controlled porosity, high surface areas, and tunable structures. However, the low electrochemical accessibility of their redox-active sites has limited COF-based devices either to thin films (<250 nm) grown on conductive substrates, or to thicker films (1 µm) when a conductive polymer is introduced into the COF pores. Electrical energy storage devices constructed from bulk microcrystalline COF powders, eliminating the need for both thin-film formation and conductive polymer guests, would offer both improved capacity and potentially scalable fabrication processes. Here we report on the synthesis and electrochemical evaluation of a new phenazine-based 2D COF (DAPH-TFP COF), as well as its composite with poly(3,4-ethylenedioxythiophene) (PEDOT). Both the COF and its PEDOT composite were evaluated as powders that were solution-cast onto bulk electrodes serving as current collectors. The unmodified DAPH-TFP COF exhibited excellent electrical access to its redox sites, even without PEDOT functionalization, and outperformed the PEDOT composite of a previously reported anthraquinone-based system. Devices containing DAPH-TFP COF were able to deliver both high energy (250 Wh/kg) and power densities (2950 W/kg), validating the promise of unmodified redox-active COFs that are easily incorporated into electrical energy storage devices.


2019 ◽  
Author(s):  
Edon Vitaku ◽  
Cara Gannett ◽  
Keith Carpenter ◽  
Luxi Shen ◽  
Hector Abruna ◽  
...  

Redox-active covalent organic frameworks (COFs) are promising materials for energy storage devices because of their high density of redox sites, permanent and controlled porosity, high surface areas, and tunable structures. However, the low electrochemical accessibility of their redox-active sites has limited COF-based devices either to thin films (<250 nm) grown on conductive substrates, or to thicker films (1 µm) when a conductive polymer is introduced into the COF pores. Electrical energy storage devices constructed from bulk microcrystalline COF powders, eliminating the need for both thin-film formation and conductive polymer guests, would offer both improved capacity and potentially scalable fabrication processes. Here we report on the synthesis and electrochemical evaluation of a new phenazine-based 2D COF (DAPH-TFP COF), as well as its composite with poly(3,4-ethylenedioxythiophene) (PEDOT). Both the COF and its PEDOT composite were evaluated as powders that were solution-cast onto bulk electrodes serving as current collectors. The unmodified DAPH-TFP COF exhibited excellent electrical access to its redox sites, even without PEDOT functionalization, and outperformed the PEDOT composite of a previously reported anthraquinone-based system. Devices containing DAPH-TFP COF were able to deliver both high energy (250 Wh/kg) and power densities (2950 W/kg), validating the promise of unmodified redox-active COFs that are easily incorporated into electrical energy storage devices.


2014 ◽  
Vol 3 (6) ◽  
pp. 265-270 ◽  
Author(s):  
Shiva Adireddy ◽  
Venkata Sreenivas Puli ◽  
Samuel Charles Sklare ◽  
Tiffany Jialin Lou ◽  
Brian Charles Riggs ◽  
...  

2013 ◽  
Vol 16 (4) ◽  
pp. 257-262 ◽  
Author(s):  
Ting Luo ◽  
Shaorong Wang ◽  
Le Shao ◽  
Jiqing Qian ◽  
Xiaofeng Ye ◽  
...  

We report a ferric-air, solid oxide battery that consists of a tubular solid oxide cell with Ca(OH)2/CaO dispersed Fe/FeOx powders integrated as the redox-active materials in the fuel chamber. The key feature here is the use of Ca(OH)2 to prevent agglomeration and coarsening of Fe/FeOx powders, and more importantly to enable in situ production of H2/H2O as the electrochemical active redox couple in the fuel electrode. The proof-of-concept solid oxide battery exhibits an energy capacity of 144 Wh kg-1-Fe at a ferric utilization of 18.8% and excellent stability in ten discharge/charge cycles with a voltage efficiency of 83% that have great potential for improvement. These results showed encouraging promise of the ferric-air, solid oxide batteries for electrical energy storage applications.


2018 ◽  
Vol 20 (7) ◽  
pp. 5001-5011 ◽  
Author(s):  
Liwei Wang ◽  
Xingyi Huang ◽  
Yingke Zhu ◽  
Pingkai Jiang

Introducing a high dielectric constant (high-k) nanofiller into a dielectric polymer is the most common way to achieve flexible nanocomposites for electrostatic energy storage devices.


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