1. Enhancing performance of capacitive deionization under high voltage by suppressing anode oxidation using a novel membrane coating electrode.
- Author
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Wang, Chengyi, Ren, Long-Fei, Ying, Diwen, Jia, Jinping, and Shao, Jiahui
- Subjects
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DEIONIZATION of water , *ELECTRODES , *OXIDATION , *ANODES , *POLYVINYL alcohol , *CHARGE transfer , *SURFACE coatings , *HIGH voltages - Abstract
High voltage operation is effective to improve salt adsorption capacity (SAC) of capacitive deionization (CDI), while this will cause performance loss during long-term operation. Herein, to address this issue, we report a simple approach to prepare novel membrane coating electrode (MCE) that polyvinyl alcohol/polyethyleneimine membrane was deposited onto activated carbon fiber (ACF) and glutaraldehyde (GA) was used for crosslinking. Compared with ACF (SAC: 13.2–20.9 mg/g, charge efficiency: 63.6%–43.9%), MCE with optimized 5 wt% GA concentration (MCE (5)) showed an improved SAC from 14.6 to 28.4 mg/g and stable charge efficiency at 80.2% when voltage increased from 0.8 V to high voltage of 1.8 V due to suppressed anode oxidation. After forty cycles experiments at 1.8 V, SAC retention of ACF declined to 71.6% caused by degradation of electrode properties, while SAC retention of MCE (5) increased to 124.7%. The deposited membrane was found to act as a barrier and inhibitor to restrict ACF oxidation, and conversions of N-containing groups and reduced charge transfer resistance of cycled MCE (5) led to superb long-term performance. It is reasonable to believe that our work provides new strategy for enhancing CDI performance by using newly developed MCE. [Display omitted] • A novel MCE was prepared firstly by depositing PVA/PEI membrane onto ACF. • MCE (5) exhibited a high SAC and improved SAC retention under a high voltage. • MCE (5) showed a stable E pzc and reduced charge transfer resistance during cycling. • PVA/PEI membrane acted as a barrier and inhibitor to suppress ACF oxidation. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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