Mechanistic Understanding of the Underlying Energy Storage Mechanism of α-MnO2-based Pseudo-Supercapacitors
© 2024 Wiley‐VCH GmbH.
| Publié dans: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 36(2024), 46 vom: 20. Nov., Seite e2408476 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2024
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| Accès à la collection: | Advanced materials (Deerfield Beach, Fla.) |
| Sujets: | Journal Article EMIMOTF in situ transmission electron microscope microscopic mechanism pseudo‐capacitance mechanism α‐MnO2 nanowires |
| Résumé: | © 2024 Wiley‐VCH GmbH. Manganese dioxide (α-MnO2) has attracted significant research interest in supercapacitors recently. However, the reaction mechanism of α-MnO2 in supercapacitors remains unclear. Therefore, a nano-supercapacitor using Environmental transmission electron microscopy (ETEM) is conducted and investigated the reaction mechanism of α-MnO2 based on three ionic liquids (ILs). It found that in the aprotic ionic liquid (AIL) 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIMOTF), α-MnO2 nanowires (NWs) undergo an oxidation reaction due to the presence of an active proton at the second position (H2) of the imidazole ring. As a result, α-MnO2 NWs undergo a phase transition and transform into Mn3O4, exhibiting pseudo-capacitive properties. Furthermore, characterization of the macroscopic α-MnO2 electrodes after cycling reveals that after the initial charging cycles, the dominant energy storage mechanism of the supercapacitor transitions from pseudo-capacitance to a dual-layer capacitance formed by the combination of Mn3O4 and unreacted α-MnO2. Simultaneously, due to the coexistence of these two energy storage mechanisms, the specific capacitance of the supercapacitor in EMIMOTF electrolyte reaches up to 80 F g-1, and the cycle number reaches as high as 1000 cycles. The results are expected to provide insights into the selection of electrolytes in supercapacitors and offer a fundamental understanding of the internal reaction mechanisms in capacitors |
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| Description: | Date Revised 15.11.2024 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202408476 |