Quinoxaline derivatives as cathode for aqueous zinc battery

• Published in: Journal of solid state electrochemistry Vol. 28; no. 2; pp. 419 - 431
• Main Authors: Chola, Noufal Merukan, Nagarale, Rajaram K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-02-2024; Springer Nature B.V
• Subjects: Analytical Chemistry; Capacitance; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Current carriers; Electrochemical analysis; Electrochemistry; Energy Storage; Functional groups; Ketones; Original Paper; Physical Chemistry; Quinoxalines; Quinoxaline; Diffusion kinetics; Stereochemistry of substituents; Aqueous zinc battery; Organic cathode
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-023-05689-2

Functional groups adjacent to the redox active center would have an uncompromising effect on the diffusion kinetics of the charge carriers. They expedite the diffusion process by extensive H-bonding, charge delocalization, and functional group polarization by tautomerism or resonance which would have long held influence on the electrochemical performance of the material. Herein, we introduced a ketonic functional group adjacent to the quinoxaline redox center which accelerates the diffusion of the charge carriers. Quinoxaline nuclei with free rotating phenyl rings (DAB) exhibited a specific capacitance of 156.4 mAhg
−1
at 50 mAg
−1
which was found drastically decreased due to the excessive dissolution of the material as well as the uncontrolled ring flipping of the phenyl rings. By introducing a ketone functional group and stagnant phenyl rings with a fused ring system the specific capacitance was found to be improved to a considerable extent. The quinoxaline redox center with a fused ring system and symmetrically placed ketone functional groups (TKQ) exhibited a specific capacitance of 286.7 mAhg
−1
at 50 mAg
−1
and remained 224.8 mAhg
−1
after prolonged 1000 cycles, with 95% coulombic efficiency and 79.4% retention in the discharge capacity. The study suggests that smart molecular engineering is necessary for excellent rate performance, rate reversibility, coulombic efficiency, and capacity retention.
Graphical abstract