https://scholars.lib.ntu.edu.tw/handle/123456789/408992
Title: | In situ crystallographic investigations of charge storage mechanisms in MnO 2-based electrochemical capacitors | Authors: | Ghodbane O. Ataherian F. Wu N.-L. Favier F. |
Keywords: | Charge-discharge mechanism;In situ X-ray diffraction;Manganese dioxides;Microstructural material changes;Supercapacitor;Synchrotron | Issue Date: | 2012 | Journal Volume: | 206 | Start page/Pages: | 454-462 | Source: | Journal of Power Sources | Abstract: | Structural behaviors of four MnO 2 allotropes are investigated by in situ synchrotron X-ray diffraction analyses upon charge/discharge cycling in LiCl and KCl aqueous media. During the anodic/cathodic scans of the 2D birnessite electrode, the interlayer spacing respectively extend/contract along the z direction by ?0.2 ?. This behavior is associated to electrostatic attractive forces between charged framework layers and hydrated electrolyte cations. In contrast, the oxidation/reduction of the 3D spinel electrode lead to the contraction/swelling of (1 1 1) crystalline planes by ?0.05 ?. Manganese-oxygen distance changes induced by Mn(III)/Mn(IV) redox reactions are assigned to such a mechanism. Structural characterizations are focused on the (0 0 2), (2 1 1), (1 1 0) and (2 0 0) planes for MnO 2 cryptomelane, while (0 0 2) and (2 0 0) planes for MnO 2 OMS-5. The 1D cryptomelane and OMS-5 electrodes also exhibit contraction/swelling processes of their structures upon discharge/charge cycling associated to deintercalation/intercalation of hydrated electrolyte cations in their channels, respectively, driven by size/steric constraints. ? 2012 Elsevier B.V. All rights reserved. |
URI: | https://scholars.lib.ntu.edu.tw/handle/123456789/408992 | ISSN: | 03787753 | DOI: | 10.1016/j.jpowsour.2012.01.103 |
Appears in Collections: | 化學工程學系 |
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