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Morphology control of CoCO3 crystals and their conversion to mesoporous Co3O4 for alkaline rechargeable batteries application.
- Source :
- CrystEngComm; 2013, Vol. 15 Issue 30, p6101-6109, 9p
- Publication Year :
- 2013
-
Abstract
- Shape-controlled synthesis of CoCO<subscript>3</subscript> crystals is achieved by a mild template- and surfactant-free solvothermal process. On switching the volume ratio of ethylene glycol (EG) in the mixed solvent, the structures of the CoCO<subscript>3</subscript> crystals change from cantaloupe-like patterns to microcubes. The formation pathway of CoCO<subscript>3</subscript> was discussed from the viewpoint of K<subscript>sp</subscript> and the equilibrium of water ionization. After calcination in air at 500 °C, the as-prepared CoCO<subscript>3</subscript> crystals convert to porous Co<subscript>3</subscript>O<subscript>4</subscript> microstructures. When used as negative electrodes of alkaline rechargeable batteries, these Co<subscript>3</subscript>O<subscript>4</subscript> samples display high discharge capacities and good cycle stability. The electrochemical reactions occurring on the Co<subscript>3</subscript>O<subscript>4</subscript> electrode are investigated by XRD, cyclic voltammetry (CV) and charge–discharge curves. In the activation process for about 20 cycles, Co<subscript>3</subscript>O<subscript>4</subscript> transforms to Co(OH)<subscript>2</subscript> in the charged process, then a large discharge capacity is obtained through Faradaic reaction between Co and Co(OH)<subscript>2</subscript>. Experimental results indicate that the discharge capacities of the obtained Co<subscript>3</subscript>O<subscript>4</subscript> samples are significantly influenced by their surface area and microstructures. Through lowering the calcination temperature to 300 °C, a mesoporous sample with a high BET surface area of 105 m<superscript>2</superscript> g<superscript>−1</superscript> and narrow particle size distribution is obtained. At a current density of 100 mA g<superscript>−1</superscript>, the discharge capacity of this Co<subscript>3</subscript>O<subscript>4</subscript> sample reaches 490.2 mA h g<superscript>−1</superscript>. After 50 cycles it can still achieve 436.9 mA h g<superscript>−1</superscript>. Meanwhile, the Co<subscript>3</subscript>O<subscript>4</subscript> sample shows enhanced rate performance, indicating great potential application in alkaline rechargeable batteries. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 14668033
- Volume :
- 15
- Issue :
- 30
- Database :
- Complementary Index
- Journal :
- CrystEngComm
- Publication Type :
- Academic Journal
- Accession number :
- 100903239
- Full Text :
- https://doi.org/10.1039/c3ce40722e