High Li storage capacity of poorly crystalline porous delta-MnO2 prepared by hydrothermal route

Nayak, Prasant Kumar and Penki, Tirupathi Rao and Munichandraiah, N (2013) High Li storage capacity of poorly crystalline porous delta-MnO2 prepared by hydrothermal route. In: Journal of Electroanalytical Chemistry, 703 . pp. 126-134.

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Abstract

Poorly crystalline porous delta-MnO2 is synthesized by hydrothermal route from a neutral aqueous solution of KMnO4 at 180 degrees C and the reaction time of 24 h. The as-synthesized sample and also the sample heated at 300 degrees C have nanopetals morphology with large surface area. On heating at temperatures 400 degrees C, there is a decrease in BET surface area and also a change in morphology from nanopetals to clusters of nanorods. Furthermore, the poorly crystalline delta-MnO2 converts into well crystalline alpha-MnO2 phase. The electrochemical lithium intercalation and de-intercalation studies in a non-aqueous electrolyte provide a high discharge specific capacity (275 mAh g(-1)) at a specific current of 40 mA g(-1) for the poorly crystalline delta-MnO2 samples. The rate capability is also high. There is a decrease in capacity on repeated charge-discharge cycling. The specific capacity values of the crystalline alpha-MnO2 samples are considerably less than the values of poorly crystalline delta-MnO2 samples. Thus, the hydrothermal route facilitates preparation of poorly crystalline electrochemically active porous MnO2.

Item Type:	Journal Article
Publication:	Journal of Electroanalytical Chemistry
Publisher:	Elsevier Science
Additional Information:	Copyright of this article belongs to Elsevier Science.
Keywords:	Porous Manganese Dioxide; Poor Crystallinity; Morphology; High Capacity; Cathode Material
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	04 Oct 2013 05:37
Last Modified:	04 Oct 2013 05:37
URI:	http://eprints.iisc.ac.in/id/eprint/47489

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