Controlled preparation of interconnected 3D hierarchical porous carbons from bacterial cellulose-based composite monoliths for supercapacitors

The controlled design and synthesis of porous carbons with anticipated microstructures and morphologies, and a high specific surface area (SSA) have been focused on for supercapacitor development. Here, hierarchical porous carbons (HPCs) with an interconnected three-dimensional morphology derived fr...

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Veröffentlicht in:Nanoscale 2020-07, Vol.12 (28), p.15261-15274
Hauptverfasser: Bai, Qiuhong, Shen, Yehua, Asoh, Taka-Aki, Li, Cong, Dan, Yong, Uyama, Hiroshi
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Sprache:eng
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Zusammenfassung:The controlled design and synthesis of porous carbons with anticipated microstructures and morphologies, and a high specific surface area (SSA) have been focused on for supercapacitor development. Here, hierarchical porous carbons (HPCs) with an interconnected three-dimensional morphology derived from a natural-based bacterial cellulose (BC) composite have been successfully prepared by thermally induced phase separation of poly(ethylene- co -vinyl alcohol) (EVOH) and subsequent carbonization/activation. The SSA and porous architectures can be controlled by fine-tuning the preparation conditions such as the precursor morphology and structure, activator dosage and activation temperature, and the relationships between the super-capacitive properties and the SSA and pore size distribution have been further investigated. The obtained porous carbon material possesses a hierarchical porous structure with moderate micropores, favorable mesopores, interconnected macropores, a high SSA of 2161 m 2 g −1 and a maximum oxygen-dopant content of 9.99%, enabling an increase in the active materials utilization efficiency and wettability. Due to the synergistic effects of these features, the obtained porous carbon electrode used in a supercapacitor shows a high specific capacitance of 420 F g −1 at 0.5 A g −1 , excellent rate performance with 75% capacitance retention at 20 A g −1 , and good cycling stability with ∼96.1% retention even after 10 000 continuous charge-discharge cycles at 5 A g −1 . Additionally, the assembled supercapacitor based on porous carbon displays a moderate energy density of 20 W h kg −1 . The good electrochemical performance and facile effective synthesis of bio-derived carbon materials with tunable porous structures indicate promising applications in supercapacitors. Morphology of a BC/EVOH monolith was tuned by changing the solvent ratio, and carbons from BC/EVOH(65%) exhibit a hierarchical porous structure, high specific capacitance, and excellent rate performance.
ISSN:2040-3364
2040-3372
DOI:10.1039/d0nr03591b