Electrochemical sodium insertion into the sol-gel birnessite manganese dioxide
✍ Scribed by S. Bach; J.P. Pereira-Ramos; N. Baffier
- Publisher
- Elsevier Science
- Year
- 1993
- Tongue
- English
- Weight
- 390 KB
- Volume
- 38
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
Electrochemical sodium insertion in the sol-gel lamellar birnessite MnO,,,,, 0.64 H,O having a high preferred orientation is investigated. Chronopotentiometric and voltammetric measurements evidence two insertion processes: the first (0 c x Q 0.35) occurs between 4.25 and 2.6 V and is accompanied by a significant decrease of the interlayer spacing while the second appears at 2.5 V (0.35 c x < 0.8) and induces no variation of the c parameter. The layered structure of the sol-gel compound allows the reversible insertion of Na+ ions and cycling galvanostatic experiments performed at 40°C. at a dischargecharge rate of C/15 show that a high specific capacity (14OAhkg-'), ie 75% of the initial capacity is achieved after the twentieth cycle.